German G. Gornalusse - Academia.edu (original) (raw)

Papers by German G. Gornalusse

Proceedings of the National Academy of Sciences of the United States of America, Aug 11, 2015

Social Science Research Network, 2019

Sexual Zika virus (ZIKV) transmission from men to women occurs less frequently than the often-det... more Sexual Zika virus (ZIKV) transmission from men to women occurs less frequently than the often-detected high viral loads in semen would suggest, but worries that this transmission route predisposes to fetal damage in pregnant women remain. To better understand sexual ZIKV pathogenesis, we studied the permissiveness of the human female genital tract to infection and the effect of semen on this process. ZIKV replicates in vaginal tissues and primary epithelial cells from the vagina, ectocervix, and endocervix and induces an innate immune response, but also continues to replicate without cytopathic effect. Infection of genital cells and tissues is strongly inhibited by extracellular vesicles (EV) in semen at physiological vesicle-to-virus ratios. Liposomes with the same composition as semen EVs also impair infection, indicating that the EV's lipid fraction, rather than their protein or RNA cargo, is responsible for this anti-viral effect. Thus, EVs in semen potently restrict ZIKV transmission, but the virus propagates well once infection in the recipient mucosa has been established.

Frontiers in Microbiology, Jun 15, 2021

Frontiers in Microbiology, Jan 20, 2022

Zika virus (ZIKV) is transmitted to people by bite of an infected mosquito and by sexual contact.... more Zika virus (ZIKV) is transmitted to people by bite of an infected mosquito and by sexual contact. ZIKV infects primary genital epithelial cells, the same cells targeted by herpes simplex virus 2 (HSV-2). HSV-2 seroprevalence is high in areas where ZIKV is endemic, but it is unknown whether HSV-2 increases the risk for ZIKV infection. Here, we found that pre-infecting female genital tract epithelial cells with HSV-2 leads to enhanced binding of ZIKV virions. This effect did not require active replication by HSV-2, implying that the effect results from the immune response to HSV-2 exposure or to viral genes expressed early in the HSV-2 lifecycle. Treating cells with toll-like receptor-3 ligand poly-I:C also lead to enhanced binding by ZIKV, which was inhibited by the JAK-STAT pathway inhibitor ruxolitinib. Blocking or knocking down the well-studied ZIKV receptor AXL did not prevent binding of ZIKV to epithelial cells, nor prevent enhanced binding in the presence of HSV-2 infection. Blocking the α5 integrin receptor did not prevent ZIKV binding to cells either. Overall, our results indicate that ZIKV binding to genital epithelial cells is not mediated entirely by a canonical receptor, but likely occurs through redundant pathways that may involve lectin receptors and glycosaminoglycans. Our studies may pave the way to new interventions that interrupt the synergism between herpes and Zika viruses.

Frontiers in Microbiology, Sep 29, 2020

medRxiv (Cold Spring Harbor Laboratory), Jul 8, 2023

Objective: Assess whether biomarkers of systemic inflammation are associated with HIV acquisition... more Objective: Assess whether biomarkers of systemic inflammation are associated with HIV acquisition or with the timing of ART initiation ("immediate", at diagnosis, versus "deferred", at 24 weeks postdiagnosis) in men-who-have-sex-with-men (MSM) and transgender women. Design: A retrospective study comparing inflammatory biomarkers in participants' specimens collected before and after ≥2 years of effective ART. Methods: Inflammatory biomarkers were measured in four longitudinally collected plasma specimens, including two plasma specimens collected from each participant before and two after HIV acquisition and confirmed ART-suppression. Biomarkers were quantified by enzyme-linked immuno-assay or Meso Scale Discovery. Statistical measures compared intra-participant and between-group changes in biomarkers. Results: Across 50 participants, the levels of C-reactive protein (CRP), monocyte chemo-attractant protein-1, tumor necrosis factor-α and interferon gamma-induced protein-10 significantly increased while leptin and lipopolysaccharide binding protein (LBP) significantly decreased following HIV infection. Randomization to deferred-ART initiation was associated with greater increases in CRP and no decreases in LBP. Multiple biomarkers varied significantly within participants' two pre-infection or two post-ARTsuppression specimens. Conclusions: Acquisition of HIV appeared to induce systemic inflammation, with elevation of biomarkers previously associated with infections and cardiovascular disease. Initiation of ART during the early weeks of infection tempered the increase in pro-inflammatory biomarkers compared to those who delayed ART for ~24 weeks after HIV diagnosis, perhaps because immediate-ART limited the size of the HIV reservoir or limited immune dysregulation. Some but not all biomarkers appeared sufficiently stable .

Molecular human reproduction, Jan 20, 2023

In addition to their role in protein translation, tRNAs can be cleaved into shorter, biologically... more In addition to their role in protein translation, tRNAs can be cleaved into shorter, biologically active fragments called tRFs. Specific tRFs from spermatocytes can propagate metabolic disorders in second generations of mice. Thus, tRFs in germline cells are a mechanism of epigenetic inheritance. It has also been shown that stress and toxins can cause alterations in tRF patterns. We were therefore interested in whether injecting illicit drugs, a major stressor, impacts tRFs in germline cells. We sequenced RNA from spermatocytes and from semen-derived exosomes from people who inject illicit drugs (PWID) and from non-drug using controls, both groups of unknown fertility status. All PWID injected opioids daily, but most also used other illicit drugs. The tRF cleavage products from Gly-GCC tRNA were markedly different between spermatocytes from PWID compared to controls. Over 90% of reads in controls mapped to shorter Gly-GCC tRFs, while in PWID only 45% did. In contrast, only 4.1% of reads in controls mapped to a longer tRFs versus 45.6% in PWID. The long/short tRF ratio was significantly higher in PWID than controls (0.23 versus 0.16, p=0.0128). We also report differential expression of a group of small nucleolar RNAs in semen-derived exosomes, including, among others, ACA14a, U19 and U3-3. Thus, PWID exhibited an altered cleavage pattern of tRNA-Gly-GCC in spermatocytes and an altered cargo of snoRNAs in semen-derived exosomes. Participants were not exclusively using opioids and were not matched with controls in terms of diet, chronic disease, or other stressors, so our finding are not conclusively linked to opioid use. However, all individuals in the PWID group did inject heroin daily. Our study indicates a potential for opioid injection and/or its associated multi-drug use habits and lifestyle changes to influence epigenetic inheritance.

Retrovirology

Background Innate immunity and type 1 interferon (IFN) defenses are critical for early control of... more Background Innate immunity and type 1 interferon (IFN) defenses are critical for early control of HIV infection within CD4 + T cells. Despite these defenses, some acutely infected cells silence viral transcription to become latently infected and form the HIV reservoir in vivo. Latently infected cells persist through antiretroviral therapy (ART) and are a major barrier to HIV cure. Here, we evaluated innate immunity and IFN responses in multiple T cell models of HIV latency, including established latent cell lines, Jurkat cells latently infected with a reporter virus, and a primary CD4 + T cell model of virologic suppression. Results We found that while latently infected T cell lines have functional RNA sensing and IFN signaling pathways, they fail to induce specific interferon-stimulated genes (ISGs) in response to innate immune activation or type 1 IFN treatment. Jurkat cells latently infected with a fluorescent reporter HIV similarly demonstrate attenuated responses to type 1 IFN....

Global heart, Jun 1, 2016

Introduction: Human embryonic stem cell-derived cardiomyocytes (hESC-CMs) can regenerate myocardi... more Introduction: Human embryonic stem cell-derived cardiomyocytes (hESC-CMs) can regenerate myocardium as they can engraft, electrically couple and remuscularize. Optimally, hESC-CMs would be banked as a source of immediate off-the-shelf therapy. However, hESC-CMs have intrinsic immunoreactivity, which would require immunosuppressive regimens to prevent rejection. A significant cause of graft rejection is the recognition of the major histocompatibility complex class I (MHC-I). Cells devoid of cell surface MHC-I through deletion of beta-2 microglobulin (B2M, sine qua non required molecule for MHC-I surface expression) may be able to avoid an immune response. Objectives: To test the differentiation potential and immunogenicity of B2M-/-hESC's. Also, to test an hESC-based cardiac regenerative therapy by utilizing CMs derived from MHC-I deficient murine neonatal cardiomyocytes (NCM). Methods: Undifferentiated B2M +/+ and B2M-/-hESCs were differentiated into cardiomyocytes and tested for cell mediated immunogenicity and expression of cardiac troponin (cTn) and MHC-I. B2M +/+ and B2M-/pregnant females were given BrdU to label NCM. B2M +/+ and B2M-/-NCMs were injected into the left ventricles of adult mice. Immunofluorescence and histology were used to detect necrosis and BrdU. Results: B2M +/+ and B2M-/-hESCs were differentiated into CM's using small molecule

Journal of Virology, 2020

A reason that there is no universal cure for HIV-1 is that the virus can hide in the genome of in... more A reason that there is no universal cure for HIV-1 is that the virus can hide in the genome of infected cells in the form of latent proviral DNA. This hidden provirus is protected from antiviral drugs until it eventually reactivates to produce new virions. It is not well understood where in the body or how this reactivation occurs. We studied HIV-1 reactivation in the female genital tract, which is often the portal of HIV-1 entry and which remains a site of infection throughout the disease. We found that the columnar epithelial cells lining the endocervix, the lower part of the uterus, are particularly effective in reactivating HIV-1 from infected T cells. This activity was enhanced by certain microbial stimuli, including herpes simplex virus 2, and blocked by antibodies against the inflammatory cytokine TNF-α. Avoiding HIV-1 reactivation could be important for maintaining a functional HIV-1 cure when antiviral therapy is stopped.

Infection and Immunity

Mycoplasma genitalium is a sexually transmitted bacterial pathogen that causes urogenital disease... more Mycoplasma genitalium is a sexually transmitted bacterial pathogen that causes urogenital disease in men and women. M. genitalium infections can persist for months to years and can ascend to the upper reproductive tract in women where it is associated with serious sequelae including pelvic inflammatory disease, tubal factor infertility, and preterm birth. An animal model is needed to understand immune evasion strategies that allow persistence, mechanisms of ascending infection, and factors associated with clearance.

Molecular therapy : the journal of the American Society of Gene Therapy, Jan 7, 2015

Many applications of pluripotent stem cells (PSCs) require efficient editing of silent chromosoma... more Many applications of pluripotent stem cells (PSCs) require efficient editing of silent chromosomal genes. Here we show that a major limitation in isolating edited clones is silencing of the selectable marker cassette after homologous recombination, and that this can be overcome by using a UCOE promoter-driven transgene. We use this strategy to edit the silent IL2RG locus in human PSCs with a recombinant adeno-associated virus (rAAV) targeting vector in the absence of potentially genotoxic, site-specific nucleases, and show that IL2RG is required for NK and T cell differentiation of human PSCs. Insertion of an active UCOE promoter into a silent locus altered the histone modification and cytosine methylation pattern of surrounding chromatin, but these changes resolved when the UCOE promoter was removed. This same approach could be used to correct IL2RG mutations in X-SCID patient-derived induced PSCs (iPSCs), to prevent graft versus host disease in regenerative medicine applications, ...

Proceedings of the National Academy of Sciences, 2015

Significance Levels of CC chemokine receptor 5 (CCR5) on T cells are a critical factor influencin... more Significance Levels of CC chemokine receptor 5 (CCR5) on T cells are a critical factor influencing HIV/AIDS susceptibility. DNA methylation is an epigenetic feature associated with lower gene expression. Here we show that the DNA methylation status of CCR5 cis -regulatory regions ( cis -regions) correlates inversely with CCR5 levels on T cells. T-cell activation induces demethylation of CCR5 cis -regions, upregulating CCR5 expression. Higher vs. lower sensitivity of CCR5 cis -regions to undergoing T-cell activation-induced demethylation is associated with increased vs. decreased CCR5 levels. Polymorphisms in CCR5 cis -regions that are associated with increased vs. decreased HIV/AIDS susceptibility are also associated with increased vs. decreased sensitivity to activation-induced demethylation. Thus, interactions among T-cell activation, CCR5 epigenetics, and genetics influence CCR5 levels on T cells and, by extension, HIV/AIDS susceptibility.

Regulatory Peptides, 2009

This study was performed to provide insight into the regulatory role of angiotensin II and arteri... more This study was performed to provide insight into the regulatory role of angiotensin II and arterial pressure on the activity of antioxidant enzymes and oxidative stress generation in the hypertensive kidney from an experimental animal model of renovascular hypertension. Aortic coarcted and sham-operated rats received vehicle, losartan or minoxidil in their drinking water. After 7 d of treatment rats were sacrificed; hypertensive kidneys were excised, and the NAD(P)H oxidase subunits expression, TBARS production, glutathione level and the activity of heme oxygenase-1 and classical antioxidant enzymes, were evaluated. Losartan administration significantly reduced oxidative stress generation decreasing NAD(P)H oxidase expression, independently of the drop in arterial pressure. On the other hand, antioxidant enzymes were regulated by arterial pressure and they were not implicated in kidney protection against oxidative damage. Findings here reported strongly suggest that clinical therapeutics with the Ang II type 1 receptor blocker prevents oxidative stress generation and may attenuate the kidney oxidative damage in the renovascular hypertension. We hypothesize that the pathway followed by the Ang II blocker to achieve this renoprotection, though independent of the primary antioxidant enzymatic system, depends on NAD(P)H oxidase downregulation.

Journal of Peptide Science, 2004

Fasciculins are peptides isolated from mamba (Dendroaspis) venoms which exert their toxic action ... more Fasciculins are peptides isolated from mamba (Dendroaspis) venoms which exert their toxic action by inhibiting acetylcholinesterase (AChE). They contain a characteristic triple stranded antiparallel β-sheet formed by residues 22-27, 34-39 and 48-53. A chimeric peptide named Fas-C, encompassing most of these sequences was synthesized using SPPS/Boc-chemistry and characterized chemically, structurally and functionally. Fas-C has two disulfide bridges, formed sequentially using dual cysteine protection. SDS-PAGE patterns, HPLC profiles and MS proved the peptide identity. Circular dichroism indicated the presence of 13.6% and 41.6% of β-sheet and β-turn, respectively, comparable to values observed in the native toxin. An inhibitory effect on eel AChE was displayed by the peptide (K i 71.6 ± 18.3 µM), although not reaching the affinity level of the parent native toxin (K i 0.3 nM). It is confirmed that the principal binding region of fasciculin to AChE resides within loop II.

AIDS, 2009

Objective-CCL3L and CCL4L genes encode HIV-suppressive chemokines, colocalize on chromosome 17q12... more Objective-CCL3L and CCL4L genes encode HIV-suppressive chemokines, colocalize on chromosome 17q12 and have copy number variation. Copy number variation of CCL3L associates with HIV-AIDS susceptibility. Here, we determined the influence of the combinatorial content of distinct CCL3L and CCL4L genes on HIV-AIDS susceptibility. Methods-By designing gene-specific assays, the association between doses of all CCL3L or CCL4L genes or their individual duplicated components (CCL3La/b and CCL4La/b) with HIV-AIDS susceptibility was determined in 298 perinatally exposed Ukrainian children. Results-The odds of transmission was increased in children with less than two copies of CCL3L or CCL4L, compared with those with at least two copies, and 10-fold higher when both mother and offspring had less than two CCL3L or CCL4L copies, compared with mother-child pairs with at least two copies. The extent of the pair-wise correlations between CCL3La, CCL3Lb, CCL4La and CCL4Lb copy number varied extensively, with an inverse correlation between CCL4L genes that transcribe a classical chemokine (CCL4La) versus aberrantly-spliced transcripts (CCL4Lb). Children possessing only CCL4Lb progressed four times faster to AIDS than those with only CCL4La. A lower content of CCL3L and CCL4L genes that transcribe classical chemokines was associated with enhanced HIV-AIDS susceptibility. Conclusion-Transmission risk is greatest when mother and offspring both have low CCL3L or CCL4L gene doses. The impact on HIV-AIDS susceptibility of the chemokine gene-rich locus on