Woong-ki Kim - Academia.edu (original) (raw)

Papers by Woong-ki Kim

Research paper thumbnail of β–Amino Ester Polymers Facilitate in Vivo DNA Transfection and Adjuvant Plasmid DNA Immunization

Molecular Therapy, 2005

Increased in vivo expression of intramuscularly delivered plasmid DNA will be essential for clini... more Increased in vivo expression of intramuscularly delivered plasmid DNA will be essential for clinical success in gene therapy and plasmid DNA vaccination. We screened polymers from a library of beta-amino esters for their ability to augment transgene expression as measured by beta-galactosidase activity and cellular immune responses. Among the candidates identified in this screen, poly[(1,6-di(acryloxyethoxy)hexane)-co-(4-aminobutanol)] enhanced plasmid DNA transgene expression by sevenfold (P=0.0001) and its immunogenicity by 70% (P=0.03). We found that polymers with moderately hydrophobic backbones and terminal alcohol groups facilitated transfection most effectively in vivo. We also observed a log-linear correlation (R2=0.93) between peak cellular immune responses and transgene activity in all evaluated polymer-plasmid DNA formulations, clarifying the relationship between immunogenicity and the quantity of expressed antigen.

Research paper thumbnail of Role of CD8 + Lymphocytes in Control and Clearance of Measles Virus Infection of Rhesus Monkeys

Journal of Virology, 2003

The creation of an improved vaccine for global measles control will require an understanding of t... more The creation of an improved vaccine for global measles control will require an understanding of the immune mechanisms of measles virus containment. To assess the role of CD8 + cytotoxic T lymphocytes in measles virus clearance, rhesus monkeys were depleted of CD8 + lymphocytes by monoclonal anti-CD8 antibody infusion and challenged with wild-type measles virus. The CD8 + lymphocyte-depleted animals exhibited a more extensive rash, higher viral loads at the peak of virus replication, and a longer duration of viremia than did the control antibody-treated animals. These findings indicate a central role for CD8 + lymphocytes in the control of measles virus infections and the importance of eliciting a cell-mediated immune response in new measles vaccine strategies.

Research paper thumbnail of Outer membrane vesicles from pathogenic bacteria initiate an inflammatory response in human endothelial cells

Journal of Surgical Research, 2013

Gram-negative bacteria release outer membrane vesicles (OMVs) during growth that contain various ... more Gram-negative bacteria release outer membrane vesicles (OMVs) during growth that contain various membrane components involved in eliciting an inflammatory response, including lipopolysaccharide and virulence factors. However, little is known about the role of OMVs in sepsis. The objective of this study was to determine how OMVs, derived from Escherichia (E.) coli, elicit the cellular responses involved in activating the inflammatory cascade, and to determine whether additional virulence factors in pathogenic OMVs augment the inflammatory response. Human umbilical endothelial cells were inoculated with OMVs from non-pathogenic E. coli (npOMV) or pathogenic E. coli (pOMV) and analyzed for adhesion protein synthesis, cytokine production, and necrosis factor (NF)-κB translocation. Flow cytometry demonstrated that human umbilical vein endothelial cells exposed to npOMV or pOMV significantly increased expression of E-selectin and intercellular adhesion molecule, with a large population of cells demonstrating increased expression of both proteins. Interleukin-6 levels were significantly elevated by 4 h after exposure to npOMV and pOMVs. NF-κB translocation to the nucleus was shown to be induced by npOMV and pOMVs. However, the role of additional virulence factors associated with pOMVs remains undefined. Both npOMVs and pOMVs are capable of initiating the inflammatory cascade in endothelial cells. OMVs trigger NF-κB translocation to the nucleus, resulting in up-regulation of adhesion molecules and cytokines, presumably for the recruitment of leukocytes. By eliciting an inflammatory response, OMVs could facilitate the transition from a localized infection to a systemic response, and ultimately sepsis.

Research paper thumbnail of The level of monocyte turnover predicts disease progression in the macaque model of AIDS

Blood, 2009

It is widely accepted that destruction of CD4+ T cells and viral load are the primary markers for... more It is widely accepted that destruction of CD4+ T cells and viral load are the primary markers for immunodeficiency in HIV-1–infected humans and in simian immunodeficiency virus (SIV)–infected macaques. However, monocyte/macrophages are also important targets of HIV/SIV infection and a critical link between innate and adaptive immunity. We therefore examined whether changes in cells of the monocyte/macrophage lineage could be linked to the pathogenesis of AIDS in the rhesus macaque model. Here, we show that massive turnover of peripheral monocytes associated with death of tissue macrophages correlates with AIDS progression in macaques. More importantly, the level of monocyte turnover was not linked to the CD4+ T-cell count and was a better predictive marker for AIDS progression than was viral load or lymphocyte activation. Our results show the importance of monocyte/macrophages in the pathogenesis of AIDS and suggest the dynamic changes of the monocyte/macrophages as a new marker for...

Research paper thumbnail of Proliferation of Perivascular Macrophages Contributes to the Development of Encephalitic Lesions in HIV-Infected Humans and in SIV-Infected Macaques

Scientific reports, Sep 9, 2016

The aim of the present study was to investigate if macrophage proliferation occurs in the brain d... more The aim of the present study was to investigate if macrophage proliferation occurs in the brain during simian immunodeficiency virus (SIV) infection of adult macaques. We examined the expression of the Ki-67 proliferation marker in the brains of uninfected and SIV-infected macaques with or without encephalitis. Double-label immunohistochemistry using antibodies against the pan-macrophage marker CD68 and Ki-67 showed that there was a significant increase in CD68+Ki-67+ cells in macaques with SIV encephalitis (SIVE) compared to uninfected and SIV-infected animals without encephalitis, a trend that was also confirmed in brain samples from patients with HIV encephalitis. Multi-label immunofluorescence for CD163 and Ki-67 confirmed that the vast majority of Ki-67+ nuclei were localized to CD163+ macrophages in perivascular cuffs and lesions. The proliferative capacity of Ki-67+ perivascular macrophages (PVM) was confirmed by their nuclear incorporation of bromodeoxyuridine. Examining SIV...

Research paper thumbnail of Preferential Destruction of Interstitial Macrophages over Alveolar Macrophages as a Cause of Pulmonary Disease in Simian Immunodeficiency Virus-Infected Rhesus Macaques

Journal of immunology (Baltimore, Md. : 1950), Jan 2, 2015

To our knowledge, this study demonstrates for the first time that the AIDS virus differentially i... more To our knowledge, this study demonstrates for the first time that the AIDS virus differentially impacts two distinct subsets of lung macrophages. The predominant macrophages harvested by bronchoalveolar lavage (BAL), alveolar macrophages (AMs), are routinely used in studies on human lung macrophages, are long-lived cells, and exhibit low turnover. Interstitial macrophages (IMs) inhabit the lung tissue, are not recovered with BAL, are shorter-lived, and exhibit higher baseline turnover rates distinct from AMs. We examined the effects of SIV infection on AMs in BAL fluid and IMs in lung tissue of rhesus macaques. SIV infection produced massive cell death of IMs that contributed to lung tissue damage. Conversely, SIV infection induced minimal cell death of AMs, and these cells maintained the lower turnover rate throughout the duration of infection. This indicates that SIV produces lung tissue damage through destruction of IMs, whereas the longer-lived AMs may serve as a virus reservoir...

Research paper thumbnail of Differentiation Kinetics of Blood Monocytes and Dendritic Cells in Macaques: Insights to Understanding Human Myeloid Cell Development

Journal of immunology (Baltimore, Md. : 1950), Jan 15, 2015

Monocyte and dendritic cell (DC) development was evaluated using in vivo BrdU pulse-chase analyse... more Monocyte and dendritic cell (DC) development was evaluated using in vivo BrdU pulse-chase analyses in rhesus macaques, and phenotype analyses of these cells in blood also were assessed by immunostaining and flow cytometry for comparisons among rhesus, cynomolgus, and pigtail macaques, as well as African green monkeys and humans. The nonhuman primate species and humans have three subsets of monocytes, CD14(+)CD16(-), CD14(+)CD16(+), and CD14(-)CD16(+) cells, which correspond to classical, intermediate, and nonclassical monocytes, respectively. In addition, there exist presently two subsets of DC, BDCA-1(+) myeloid DC and CD123(+) plasmacytoid DC, that were first confirmed in rhesus macaque blood. Following BrdU inoculation, labeled cells first appeared in CD14(+)CD16(-) monocytes, then in CD14(+)CD16(+) cells, and finally in CD14(-)CD16(+) cells, thus defining different stages of monocyte maturation. A fraction of the classical CD14(+)CD16(-) monocytes gradually expressed CD16(+) to ...

Research paper thumbnail of Role of peripheral immune response in microglia activation and regulation of brain chemokine and proinflammatory cytokine responses induced during VSV encephalitis

Journal of Neuroimmunology, 2014

Research paper thumbnail of Magnetic resonance spectroscopy reveals that activated monocytes contribute to neuronal injury in SIV neuroAIDS

Journal of Clinical Investigation, 2005

Research paper thumbnail of Vasoactive intestinal peptide and pituitary adenylate cyclase-activating polypeptide inhibit CBP–NF-B interaction in activated microglia

Biochemical and Biophysical Research Communications, 2002

The vasoactive intestinal peptide (VIP) and the pituitary adenylate cyclase-activating polypeptid... more The vasoactive intestinal peptide (VIP) and the pituitary adenylate cyclase-activating polypeptide (PACAP), two immunomodulatory neuropeptides, act as anti-inflammatory factors for activated microglia, by inhibiting the production of pro-inflammatory factors, mainly mediated through the inhibition of NF-jB nuclear translocation and DNA binding. An additional regulatory element in the NF-jB transcriptional activity is the coactivator CBP, which links p65 with components of the basal transcriptional machinery. The present report demonstrates that VIP and PACAP inhibit the formation of p65/CBP complexes and that this event is directly related to the neuropeptide inhibition of NF-jB transcriptional activity. Since CBP is in limiting amounts in the nucleus and is capable of interacting with several transcriptional factors, competition for CBP provides another mechanism for transcriptional regulation. VIP and PACAP increase CBP-binding to CREB, replacing p65/CBP with CREB/CBP complexes in activated microglia. This is due to VIP/PACAP-induced increases in CREB phosphorylation/activation and is mediated through the specific VPAC1 receptor and the cAMP/PKA pathway. The VIP/PACAP interference with the p65/CBP interaction in activated microglia may represent a significant element in the regulation of the inflammatory response in the CNS by the endogenous neuropeptides.

Research paper thumbnail of Distinct macrophage subpopulations regulate viral encephalitis but not viral clearance in the CNS

Journal of Neuroimmunology, 2010

Research paper thumbnail of Development of Droplet Digital PCR-Based Assays to Quantify HIV Proviral and Integrated DNA in Brain Tissues from Viremic Individuals with Encephalitis and Virally Suppressed Aviremic Individuals

Microbiology Spectrum

We developed ddPCR assays to quantitatively measure HIV DNA and used this ddPCR assays to detect ... more We developed ddPCR assays to quantitatively measure HIV DNA and used this ddPCR assays to detect and quantitatively measure HIV DNA in the archived brain tissues from HIV patients. The tissue viral loads assessed by ddPCR was highly correlative with those assessed by qPCR.

Research paper thumbnail of Expression of the Mannose Receptor CD206 in HIV and SIV Encephalitis: A Phenotypic Switch of Brain Perivascular Macrophages with Virus Infection

Journal of Neuroimmune Pharmacology, 2014

Research paper thumbnail of Short-Term Sleep Fragmentation Dysregulates Autophagy in a Brain Region-Specific Manner

Life

In this study, we investigated autophagy, glial activation status, and corticotropin releasing fa... more In this study, we investigated autophagy, glial activation status, and corticotropin releasing factor (CRF) signaling in the brains of mice after 5 days of sleep fragmentation (SF). Three different brain regions including the striatum, hippocampus, and frontal cortex were selected for examination based on roles in sleep regulation and sensitivity to sleep disruption. For autophagy, we monitored the levels of various autophagic induction markers including beclin1, LC3II, and p62 as well as the levels of lysosomal associated membrane protein 1 and 2 (LAMP1/2) and the transcription factor EB (TFEB) which are critical for lysosome function and autophagy maturation stage. For the status of microglia and astrocytes, we determined the levels of Iba1 and GFAP in these brain regions. We also measured the levels of CRF and its cognate receptors 1 and 2 (CRFR1/2). Our results showed that 5 days of SF dysregulated autophagy in the striatum and hippocampus but not in the frontal cortex. Addition...

Research paper thumbnail of Understanding the Heterogeneity of Human Pericyte Subsets in Blood–Brain Barrier Homeostasis and Neurological Diseases

Cells

Pericytes are increasingly recognized as being important in the control of blood–brain barrier pe... more Pericytes are increasingly recognized as being important in the control of blood–brain barrier permeability and vascular flow. Research on this important cell type has been hindered by widespread confusion regarding the phenotypic identity and nomenclature of pericytes and other perivascular cell types. In addition, pericyte heterogeneity and mouse–human species differences have contributed to confusion. Herein we summarize our present knowledge on the identification of pericytes and pericyte subsets in humans, primarily focusing on recent findings in humans and nonhuman primates. Precise identification and definition of pericytes and pericyte subsets in humans may help us to better understand pericyte biology and develop new therapeutic approaches specifically targeting disease-associated pericyte subsets.

Research paper thumbnail of Perivascular macrophages in the neonatal macaque brain undergo massive necroptosis after simian immunodeficiency virus infection

Research paper thumbnail of Lack of susceptibility in neonatally infected rhesus macaques to simian immunodeficiency virus-induced encephalitis

Journal of NeuroVirology

Despite combination antiretroviral therapies making HIVa chronic rather than terminal condition f... more Despite combination antiretroviral therapies making HIVa chronic rather than terminal condition for many people, the prevalence of HIV-associated neurocognitive disorders (HAND) is increasing. This is especially problematic for children living with HIV. Children diagnosed HAND rarely display the hallmark pathology of HIV encephalitis in adults, namely infected macrophages and multinucleated giant cells in the brain. This finding has also been documented in rhesus macaques infected perinatally with simian immunodeficiency virus (SIV). However, the extent and mechanisms of lack of susceptibility to encephalitis in perinatally HIV-infected children remain unclear. In the current study, we compared brains of macaques infected with pathogenic strains of SIV at different ages to determine neuropathology, correlates of neuroinflammation, and potential underlying mechanisms. Encephalitis was not found in the macaques infected within 24 h of birth despite similar high plasma viral load and high monocyte turnover. Macaques developed encephalitis only when they were infected after 4 months of age. Lower numbers of CCR5-positive cells in the brain, combined with a less leaky blood-brain barrier, may be responsible for the decreased virus infection in the brain and consequently the absence of encephalitis in newborn macaques infected with SIV.

Research paper thumbnail of Overexpression and Activation of Colony‐Stimulating Factor 1 Receptor in the SIV /Macaque Model of HIV Infection and Neuro HIV

Research paper thumbnail of Dysregulation of sonic hedgehog pathway and pericytes in the brain after lentiviral infection

Journal of Neuroinflammation

Background: Impairment of the blood-brain barrier (BBB) has been associated with cognitive declin... more Background: Impairment of the blood-brain barrier (BBB) has been associated with cognitive decline in many CNS diseases, including HIV-associated neurocognitive disorders (HAND). Recent research suggests an important role for the Sonic hedgehog (Shh) signaling pathway in the maintenance of BBB integrity under both physiological and pathological conditions. Methods: In the present study, we sought to examine the expression of Shh and its downstream effectors in relation to brain pericytes and BBB integrity in HIV-infected humans and rhesus macaques infected with simian immunodeficiency virus (SIV), an animal model of HIV infection and CNS disease. Cortical brain tissues from uninfected (n = 4) and SIV-infected macaques with (SIVE, n = 6) or without encephalitis (SIVnoE, n = 4) were examined using multi-label, semi-quantitative immunofluorescence microscopy of Shh, netrin-1, tight junction protein zona occludens 1 (ZO1), glial fibrillary acidic protein, CD163, platelet-derived growth factor receptor b (PDGFRB), glucose transporter 1, fibrinogen, and SIV Gag p28. Results: While Shh presence in the brain persisted during HIV/SIV infection, both netrin-1 immunoreactivity and the size of PDGFRB+ pericytes, a cellular source of netrin-1, were increased around non-lesion-associated vessels in encephalitis compared to uninfected brain or brain without encephalitis, but were completely absent in encephalitic lesions. Hypertrophied pericytes were strongly localized in areas of fibrinogen extravasation and showed the presence of intracellular SIVp28 and HIVp24 by immunofluorescence in all SIV and HIV encephalitis cases examined, respectively. Conclusions: The lack of pericytes and netrin-1 in encephalitic lesions, in line with downregulation of ZO1 on the fenestrated endothelium, suggests that pericyte loss, despite the strong presence of Shh, contributes to HIV/SIV-induced BBB disruption and neuropathogenesis in HAND.

Research paper thumbnail of Reply to Letter to the Editor

Journal of Neuroimmune Pharmacology

Research paper thumbnail of β–Amino Ester Polymers Facilitate in Vivo DNA Transfection and Adjuvant Plasmid DNA Immunization

Molecular Therapy, 2005

Increased in vivo expression of intramuscularly delivered plasmid DNA will be essential for clini... more Increased in vivo expression of intramuscularly delivered plasmid DNA will be essential for clinical success in gene therapy and plasmid DNA vaccination. We screened polymers from a library of beta-amino esters for their ability to augment transgene expression as measured by beta-galactosidase activity and cellular immune responses. Among the candidates identified in this screen, poly[(1,6-di(acryloxyethoxy)hexane)-co-(4-aminobutanol)] enhanced plasmid DNA transgene expression by sevenfold (P=0.0001) and its immunogenicity by 70% (P=0.03). We found that polymers with moderately hydrophobic backbones and terminal alcohol groups facilitated transfection most effectively in vivo. We also observed a log-linear correlation (R2=0.93) between peak cellular immune responses and transgene activity in all evaluated polymer-plasmid DNA formulations, clarifying the relationship between immunogenicity and the quantity of expressed antigen.

Research paper thumbnail of Role of CD8 + Lymphocytes in Control and Clearance of Measles Virus Infection of Rhesus Monkeys

Journal of Virology, 2003

The creation of an improved vaccine for global measles control will require an understanding of t... more The creation of an improved vaccine for global measles control will require an understanding of the immune mechanisms of measles virus containment. To assess the role of CD8 + cytotoxic T lymphocytes in measles virus clearance, rhesus monkeys were depleted of CD8 + lymphocytes by monoclonal anti-CD8 antibody infusion and challenged with wild-type measles virus. The CD8 + lymphocyte-depleted animals exhibited a more extensive rash, higher viral loads at the peak of virus replication, and a longer duration of viremia than did the control antibody-treated animals. These findings indicate a central role for CD8 + lymphocytes in the control of measles virus infections and the importance of eliciting a cell-mediated immune response in new measles vaccine strategies.

Research paper thumbnail of Outer membrane vesicles from pathogenic bacteria initiate an inflammatory response in human endothelial cells

Journal of Surgical Research, 2013

Gram-negative bacteria release outer membrane vesicles (OMVs) during growth that contain various ... more Gram-negative bacteria release outer membrane vesicles (OMVs) during growth that contain various membrane components involved in eliciting an inflammatory response, including lipopolysaccharide and virulence factors. However, little is known about the role of OMVs in sepsis. The objective of this study was to determine how OMVs, derived from Escherichia (E.) coli, elicit the cellular responses involved in activating the inflammatory cascade, and to determine whether additional virulence factors in pathogenic OMVs augment the inflammatory response. Human umbilical endothelial cells were inoculated with OMVs from non-pathogenic E. coli (npOMV) or pathogenic E. coli (pOMV) and analyzed for adhesion protein synthesis, cytokine production, and necrosis factor (NF)-κB translocation. Flow cytometry demonstrated that human umbilical vein endothelial cells exposed to npOMV or pOMV significantly increased expression of E-selectin and intercellular adhesion molecule, with a large population of cells demonstrating increased expression of both proteins. Interleukin-6 levels were significantly elevated by 4 h after exposure to npOMV and pOMVs. NF-κB translocation to the nucleus was shown to be induced by npOMV and pOMVs. However, the role of additional virulence factors associated with pOMVs remains undefined. Both npOMVs and pOMVs are capable of initiating the inflammatory cascade in endothelial cells. OMVs trigger NF-κB translocation to the nucleus, resulting in up-regulation of adhesion molecules and cytokines, presumably for the recruitment of leukocytes. By eliciting an inflammatory response, OMVs could facilitate the transition from a localized infection to a systemic response, and ultimately sepsis.

Research paper thumbnail of The level of monocyte turnover predicts disease progression in the macaque model of AIDS

Blood, 2009

It is widely accepted that destruction of CD4+ T cells and viral load are the primary markers for... more It is widely accepted that destruction of CD4+ T cells and viral load are the primary markers for immunodeficiency in HIV-1–infected humans and in simian immunodeficiency virus (SIV)–infected macaques. However, monocyte/macrophages are also important targets of HIV/SIV infection and a critical link between innate and adaptive immunity. We therefore examined whether changes in cells of the monocyte/macrophage lineage could be linked to the pathogenesis of AIDS in the rhesus macaque model. Here, we show that massive turnover of peripheral monocytes associated with death of tissue macrophages correlates with AIDS progression in macaques. More importantly, the level of monocyte turnover was not linked to the CD4+ T-cell count and was a better predictive marker for AIDS progression than was viral load or lymphocyte activation. Our results show the importance of monocyte/macrophages in the pathogenesis of AIDS and suggest the dynamic changes of the monocyte/macrophages as a new marker for...

Research paper thumbnail of Proliferation of Perivascular Macrophages Contributes to the Development of Encephalitic Lesions in HIV-Infected Humans and in SIV-Infected Macaques

Scientific reports, Sep 9, 2016

The aim of the present study was to investigate if macrophage proliferation occurs in the brain d... more The aim of the present study was to investigate if macrophage proliferation occurs in the brain during simian immunodeficiency virus (SIV) infection of adult macaques. We examined the expression of the Ki-67 proliferation marker in the brains of uninfected and SIV-infected macaques with or without encephalitis. Double-label immunohistochemistry using antibodies against the pan-macrophage marker CD68 and Ki-67 showed that there was a significant increase in CD68+Ki-67+ cells in macaques with SIV encephalitis (SIVE) compared to uninfected and SIV-infected animals without encephalitis, a trend that was also confirmed in brain samples from patients with HIV encephalitis. Multi-label immunofluorescence for CD163 and Ki-67 confirmed that the vast majority of Ki-67+ nuclei were localized to CD163+ macrophages in perivascular cuffs and lesions. The proliferative capacity of Ki-67+ perivascular macrophages (PVM) was confirmed by their nuclear incorporation of bromodeoxyuridine. Examining SIV...

Research paper thumbnail of Preferential Destruction of Interstitial Macrophages over Alveolar Macrophages as a Cause of Pulmonary Disease in Simian Immunodeficiency Virus-Infected Rhesus Macaques

Journal of immunology (Baltimore, Md. : 1950), Jan 2, 2015

To our knowledge, this study demonstrates for the first time that the AIDS virus differentially i... more To our knowledge, this study demonstrates for the first time that the AIDS virus differentially impacts two distinct subsets of lung macrophages. The predominant macrophages harvested by bronchoalveolar lavage (BAL), alveolar macrophages (AMs), are routinely used in studies on human lung macrophages, are long-lived cells, and exhibit low turnover. Interstitial macrophages (IMs) inhabit the lung tissue, are not recovered with BAL, are shorter-lived, and exhibit higher baseline turnover rates distinct from AMs. We examined the effects of SIV infection on AMs in BAL fluid and IMs in lung tissue of rhesus macaques. SIV infection produced massive cell death of IMs that contributed to lung tissue damage. Conversely, SIV infection induced minimal cell death of AMs, and these cells maintained the lower turnover rate throughout the duration of infection. This indicates that SIV produces lung tissue damage through destruction of IMs, whereas the longer-lived AMs may serve as a virus reservoir...

Research paper thumbnail of Differentiation Kinetics of Blood Monocytes and Dendritic Cells in Macaques: Insights to Understanding Human Myeloid Cell Development

Journal of immunology (Baltimore, Md. : 1950), Jan 15, 2015

Monocyte and dendritic cell (DC) development was evaluated using in vivo BrdU pulse-chase analyse... more Monocyte and dendritic cell (DC) development was evaluated using in vivo BrdU pulse-chase analyses in rhesus macaques, and phenotype analyses of these cells in blood also were assessed by immunostaining and flow cytometry for comparisons among rhesus, cynomolgus, and pigtail macaques, as well as African green monkeys and humans. The nonhuman primate species and humans have three subsets of monocytes, CD14(+)CD16(-), CD14(+)CD16(+), and CD14(-)CD16(+) cells, which correspond to classical, intermediate, and nonclassical monocytes, respectively. In addition, there exist presently two subsets of DC, BDCA-1(+) myeloid DC and CD123(+) plasmacytoid DC, that were first confirmed in rhesus macaque blood. Following BrdU inoculation, labeled cells first appeared in CD14(+)CD16(-) monocytes, then in CD14(+)CD16(+) cells, and finally in CD14(-)CD16(+) cells, thus defining different stages of monocyte maturation. A fraction of the classical CD14(+)CD16(-) monocytes gradually expressed CD16(+) to ...

Research paper thumbnail of Role of peripheral immune response in microglia activation and regulation of brain chemokine and proinflammatory cytokine responses induced during VSV encephalitis

Journal of Neuroimmunology, 2014

Research paper thumbnail of Magnetic resonance spectroscopy reveals that activated monocytes contribute to neuronal injury in SIV neuroAIDS

Journal of Clinical Investigation, 2005

Research paper thumbnail of Vasoactive intestinal peptide and pituitary adenylate cyclase-activating polypeptide inhibit CBP–NF-B interaction in activated microglia

Biochemical and Biophysical Research Communications, 2002

The vasoactive intestinal peptide (VIP) and the pituitary adenylate cyclase-activating polypeptid... more The vasoactive intestinal peptide (VIP) and the pituitary adenylate cyclase-activating polypeptide (PACAP), two immunomodulatory neuropeptides, act as anti-inflammatory factors for activated microglia, by inhibiting the production of pro-inflammatory factors, mainly mediated through the inhibition of NF-jB nuclear translocation and DNA binding. An additional regulatory element in the NF-jB transcriptional activity is the coactivator CBP, which links p65 with components of the basal transcriptional machinery. The present report demonstrates that VIP and PACAP inhibit the formation of p65/CBP complexes and that this event is directly related to the neuropeptide inhibition of NF-jB transcriptional activity. Since CBP is in limiting amounts in the nucleus and is capable of interacting with several transcriptional factors, competition for CBP provides another mechanism for transcriptional regulation. VIP and PACAP increase CBP-binding to CREB, replacing p65/CBP with CREB/CBP complexes in activated microglia. This is due to VIP/PACAP-induced increases in CREB phosphorylation/activation and is mediated through the specific VPAC1 receptor and the cAMP/PKA pathway. The VIP/PACAP interference with the p65/CBP interaction in activated microglia may represent a significant element in the regulation of the inflammatory response in the CNS by the endogenous neuropeptides.

Research paper thumbnail of Distinct macrophage subpopulations regulate viral encephalitis but not viral clearance in the CNS

Journal of Neuroimmunology, 2010

Research paper thumbnail of Development of Droplet Digital PCR-Based Assays to Quantify HIV Proviral and Integrated DNA in Brain Tissues from Viremic Individuals with Encephalitis and Virally Suppressed Aviremic Individuals

Microbiology Spectrum

We developed ddPCR assays to quantitatively measure HIV DNA and used this ddPCR assays to detect ... more We developed ddPCR assays to quantitatively measure HIV DNA and used this ddPCR assays to detect and quantitatively measure HIV DNA in the archived brain tissues from HIV patients. The tissue viral loads assessed by ddPCR was highly correlative with those assessed by qPCR.

Research paper thumbnail of Expression of the Mannose Receptor CD206 in HIV and SIV Encephalitis: A Phenotypic Switch of Brain Perivascular Macrophages with Virus Infection

Journal of Neuroimmune Pharmacology, 2014

Research paper thumbnail of Short-Term Sleep Fragmentation Dysregulates Autophagy in a Brain Region-Specific Manner

Life

In this study, we investigated autophagy, glial activation status, and corticotropin releasing fa... more In this study, we investigated autophagy, glial activation status, and corticotropin releasing factor (CRF) signaling in the brains of mice after 5 days of sleep fragmentation (SF). Three different brain regions including the striatum, hippocampus, and frontal cortex were selected for examination based on roles in sleep regulation and sensitivity to sleep disruption. For autophagy, we monitored the levels of various autophagic induction markers including beclin1, LC3II, and p62 as well as the levels of lysosomal associated membrane protein 1 and 2 (LAMP1/2) and the transcription factor EB (TFEB) which are critical for lysosome function and autophagy maturation stage. For the status of microglia and astrocytes, we determined the levels of Iba1 and GFAP in these brain regions. We also measured the levels of CRF and its cognate receptors 1 and 2 (CRFR1/2). Our results showed that 5 days of SF dysregulated autophagy in the striatum and hippocampus but not in the frontal cortex. Addition...

Research paper thumbnail of Understanding the Heterogeneity of Human Pericyte Subsets in Blood–Brain Barrier Homeostasis and Neurological Diseases

Cells

Pericytes are increasingly recognized as being important in the control of blood–brain barrier pe... more Pericytes are increasingly recognized as being important in the control of blood–brain barrier permeability and vascular flow. Research on this important cell type has been hindered by widespread confusion regarding the phenotypic identity and nomenclature of pericytes and other perivascular cell types. In addition, pericyte heterogeneity and mouse–human species differences have contributed to confusion. Herein we summarize our present knowledge on the identification of pericytes and pericyte subsets in humans, primarily focusing on recent findings in humans and nonhuman primates. Precise identification and definition of pericytes and pericyte subsets in humans may help us to better understand pericyte biology and develop new therapeutic approaches specifically targeting disease-associated pericyte subsets.

Research paper thumbnail of Perivascular macrophages in the neonatal macaque brain undergo massive necroptosis after simian immunodeficiency virus infection

Research paper thumbnail of Lack of susceptibility in neonatally infected rhesus macaques to simian immunodeficiency virus-induced encephalitis

Journal of NeuroVirology

Despite combination antiretroviral therapies making HIVa chronic rather than terminal condition f... more Despite combination antiretroviral therapies making HIVa chronic rather than terminal condition for many people, the prevalence of HIV-associated neurocognitive disorders (HAND) is increasing. This is especially problematic for children living with HIV. Children diagnosed HAND rarely display the hallmark pathology of HIV encephalitis in adults, namely infected macrophages and multinucleated giant cells in the brain. This finding has also been documented in rhesus macaques infected perinatally with simian immunodeficiency virus (SIV). However, the extent and mechanisms of lack of susceptibility to encephalitis in perinatally HIV-infected children remain unclear. In the current study, we compared brains of macaques infected with pathogenic strains of SIV at different ages to determine neuropathology, correlates of neuroinflammation, and potential underlying mechanisms. Encephalitis was not found in the macaques infected within 24 h of birth despite similar high plasma viral load and high monocyte turnover. Macaques developed encephalitis only when they were infected after 4 months of age. Lower numbers of CCR5-positive cells in the brain, combined with a less leaky blood-brain barrier, may be responsible for the decreased virus infection in the brain and consequently the absence of encephalitis in newborn macaques infected with SIV.

Research paper thumbnail of Overexpression and Activation of Colony‐Stimulating Factor 1 Receptor in the SIV /Macaque Model of HIV Infection and Neuro HIV

Research paper thumbnail of Dysregulation of sonic hedgehog pathway and pericytes in the brain after lentiviral infection

Journal of Neuroinflammation

Background: Impairment of the blood-brain barrier (BBB) has been associated with cognitive declin... more Background: Impairment of the blood-brain barrier (BBB) has been associated with cognitive decline in many CNS diseases, including HIV-associated neurocognitive disorders (HAND). Recent research suggests an important role for the Sonic hedgehog (Shh) signaling pathway in the maintenance of BBB integrity under both physiological and pathological conditions. Methods: In the present study, we sought to examine the expression of Shh and its downstream effectors in relation to brain pericytes and BBB integrity in HIV-infected humans and rhesus macaques infected with simian immunodeficiency virus (SIV), an animal model of HIV infection and CNS disease. Cortical brain tissues from uninfected (n = 4) and SIV-infected macaques with (SIVE, n = 6) or without encephalitis (SIVnoE, n = 4) were examined using multi-label, semi-quantitative immunofluorescence microscopy of Shh, netrin-1, tight junction protein zona occludens 1 (ZO1), glial fibrillary acidic protein, CD163, platelet-derived growth factor receptor b (PDGFRB), glucose transporter 1, fibrinogen, and SIV Gag p28. Results: While Shh presence in the brain persisted during HIV/SIV infection, both netrin-1 immunoreactivity and the size of PDGFRB+ pericytes, a cellular source of netrin-1, were increased around non-lesion-associated vessels in encephalitis compared to uninfected brain or brain without encephalitis, but were completely absent in encephalitic lesions. Hypertrophied pericytes were strongly localized in areas of fibrinogen extravasation and showed the presence of intracellular SIVp28 and HIVp24 by immunofluorescence in all SIV and HIV encephalitis cases examined, respectively. Conclusions: The lack of pericytes and netrin-1 in encephalitic lesions, in line with downregulation of ZO1 on the fenestrated endothelium, suggests that pericyte loss, despite the strong presence of Shh, contributes to HIV/SIV-induced BBB disruption and neuropathogenesis in HAND.

Research paper thumbnail of Reply to Letter to the Editor

Journal of Neuroimmune Pharmacology