Asgar Zaheer | University of Missouri Columbia (original) (raw)

Papers by Asgar Zaheer

The FASEB Journal, Apr 1, 2013

Stroke, Feb 1, 2014

Background and purpose: Ischemic stroke is a leading cause of death and disability worldwide, and... more Background and purpose: Ischemic stroke is a leading cause of death and disability worldwide, and the treatment options are limited. Interleukin-33 (IL-33) is a newly recognized IL-1 family cytokine which signals via its ST2 receptor, and acts as a key regulator of inflammation. However, the expression of IL-33 in the brain was not well studied and its expression in ischemic stroke remains to be elucidated. In the present study, we measured IL-33 and ST2 levels and examine the correlation of IL-33 expression with brain damage and functional outcome following ischemic stroke. Methods: IL-33 expression was examined in ischemic brain hemisphere. Mice were subjected to middle cerebral artery occlusion (MCAO) for 1 hr using a filament model, followed by 23 hrs reperfusion. Briefly, mice were anesthetized with 1-1.5% isoflurane mixed with medical oxygen. Body temperature was maintained at 37°C ± 1.0 using a heating pad. At 23 hours after ischemia/reperfusion, mice were tested for neurological scores and were sacrificed for the estimation of IL-33 and ST2 expression. Expression of IL-33 and its receptor ST2 was monitored by ELISA, Western blot and immunohistochemistry. The neurobehavioral scores, infarction volumes, expression of NF-kB and proinflammatory cytokines were evaluated after ischemia/reperfusion. Results: We found significantly increased expression level of IL-33 and ST2 in the MCAO mice as compare to the saline treated control mice. Moreover, treating the MCAO mice with recombinant IL-33 increases the brain injury and worsens neurological deficits in MCAO mice as compare to control mice. Interestingly, increased ischemic brain damage and neurological deficits were largely abrogated in mice treated with IL-33 neutralizing antibody. Conclusion: These findings provide the first evidence that IL-33/ST2 signaling plays an important role in the pathogenesis of stroke. Moreover, IL-33 exacerbates inflammatory brain injury after ischemic stroke and treatment with specific IL-33 neutralizing antibody inhibited the ischemic brain injury. Therefore, blocking the IL-33 may represent an efficient therapy in stroke.

Surgical Neurology International, Jul 27, 2021

Neurobiology of Disease, Dec 1, 2010

Neurochemical Research, Dec 1, 1995

1. Although glial cells in culture are known to secrete growth factors and are also known to be r... more 1. Although glial cells in culture are known to secrete growth factors and are also known to be responsive to some of them, detailed comparisons are difficult because the bulk of information was based on various animals of origin, developmental stages, growth properties, culture age, and culture conditions. 2. To present a unified picture of the growth factors and their receptors found in glial cells, we surveyed the expression of messenger RNAs of a panel of growth factors and receptors, using reverse transcription-polymerase chain reaction (RT-PCR), in three common glial cell types: rat astrocytes in primary culture, rat glioma line C6, and human glioma line A172. 3. We observed that normal and neoplastic glial cells in culture express multiple growth factors and also possess most of the receptors to these factors, suggesting multiple autocrine functions. In addition, glia produce growth factors known to be capable of acting on neurons, implicating paracrine function involving gila-neuron interaction. Glial cells also produce growth factors and receptors that are capable of communicating with hematopoietic cells, suggesting

Biochemical and Biophysical Research Communications, Sep 1, 1990

Recombinant human glia maturation factor beta (r-hGMF-beta) is a single-chain polypeptide (141 am... more Recombinant human glia maturation factor beta (r-hGMF-beta) is a single-chain polypeptide (141 amino acid residues) containing three cysteines, at positions 7, 86 and 95. Nascent r-hGMF-beta exists in the reduced state and has no biological activity. The protein can be activated through oxidative refolding by incubation with a mixture of reduced and oxidized glutathione. Reverse-phase HPLC analysis of the refolded r-hGMF-beta shows the presence of four peaks, corresponding to the reduced form plus three newly generated intrachain disulfide-containing isoforms predicted from the number of cysteine residues. Only one isoform shows biological activity when tested for growth suppression on C6 glioma cells. We infer from the HPLC elution pattern that the active form contains the disulfide bridge Cys86-Cys95.

Biochemical and Biophysical Research Communications, Sep 1, 1981

Abstract (Na++K+)-ATPase was purified from human kidney of normal and tumor tissue with specific ... more Abstract (Na++K+)-ATPase was purified from human kidney of normal and tumor tissue with specific activities of 100.0 and 16.6 μmol Pi/mg/h, respectively. The antitumor proteins, macromomycin, largomycin, and NSC 327459 (50 μg/ml each) caused 70 to 90% inhibition of (Na++K+)-ATPase from tumor tissue, whereas auromomycin had no effect. (Na++K+)-ATPase from both sources could be phosphorylated by rabbit muscle protein kinase; there was 3 to 6-fold stimulation of phosphorylation by cyclic AMP. Phosphorylation resulted in 70 to 80% decrease in (Na++K+)-ATPase activity, and caused the normal enzyme to become sensitive to inhibition by macromomycin.

Brain Research, Feb 1, 2011

Glia maturation factor (GMF), a protein primarily localized in the central nervous system (CNS) w... more Glia maturation factor (GMF), a protein primarily localized in the central nervous system (CNS) was isolated, sequenced and cloned in our laboratory. We previously demonstrated that GMF mediates the experimental autoimmune encephalomyelitis (EAE)-induced production of proinflammatory cytokines and chemokines in the central nervous system of mice. In the present study we show that immunization with myelin oligodendrocyte glycoprotein peptide 35-55 (MOG35-55) caused an early onset (day 7-9 post immunization) and severe EAE with a mean peak score of 3.5 ± 0.5 in mice. Neutralization of GMF with four injections of anti-GMF antibody 5 to 11 days postimmunization delayed the time of onset (day 12-14 post immunization) and significantly reduced the severity of EAE (mean peak score of 1.5 ± 0.4). Consistent with these clinical scores, histological examination of the CNS of these mice revealed profound differences between GMF-antibody treated mice and isotype matched control-antibody treated mice. Histological analysis of the spinal cord and brain showed severe inflammation and demyelination in the control antibody-treated mice whereas significantly reduced inflammation and demyelination was detected in GMF-antibody-treated mice at day 8, 16, and 24 post immunization. The decreased incidence and reduced severity of EAE in GMF-antibody-treated mice was consistent with the significantly reduced expressions of proinflammatory cytokines and chemokines. Our overall results demonstrate that neutralization of endogenous GMF with an affinity purified GMF antibody significantly decreased the inflammation, severity and progression of immunization induced active, passive and relapsing-remitting EAE. Treatment of mice with isotype-matched control antibody did not have any effect on EAE. Taken together, these results demonstrate the critical role of GMF in EAE, and GMF antibody as a potent anti-inflammatory therapeutic agent for effectively suppressing EAE in mouse models of major types of multiple sclerosis (MS).

Biochemical and Biophysical Research Communications, Sep 1, 1998

In order to study the intracellular regulatory function of glia maturation factor (GMF) in neuron... more In order to study the intracellular regulatory function of glia maturation factor (GMF) in neuronal cells, we achieved a 10-fold overexpression of GMF in the rat pheochromocytoma cell line PC12 by infection with a replication-defective human adenovirus carrying a rat GMF cDNA insert. These cells showed a 3.6-fold increase in the activity of p38 MAP kinase, a 3.8-fold increase in the activity of MAPKAP-K2 (MAP kinaseactivated protein kinase 2), and a 4.2-fold increase in the activity of tyrosine hydroxylase (TH). We also detected an increase in the phosphorylation of TH and the 25-kDa heat shock protein (Hsp25) without a concomitant increase in their corresponding protein levels, suggesting a posttranslational modification. It was previously established that in PC12 cells, MAPKAP-K2 is an immediate target of p38, and both TH and Hsp25 are immediate targets of MAPKAP-K2. The current in vivo results are in concordance with our earlier in vitro finding that GMF promotes the activity of p38, and they implicate the participation of GMF in stressinduced catecholamine synthesis.

Brain Research, May 1, 2007

Pro-inflammatory cytokines/chemokines are implemented in the pathogenesis of experimental autoimm... more Pro-inflammatory cytokines/chemokines are implemented in the pathogenesis of experimental autoimmune encephalomyelitis (EAE), an animal model with clinical and pathological similarities to multiple sclerosis. We have previously shown that over-expression of glia maturation factor (GMF) in glial cells cause excessive production and secretion of pro-inflammatory cytokines/chemokines sufficient to destroy the myelin forming oligodendroglial cell in-vitro. In this present investigation, we evaluate the expression of pro-inflammatory mediators in the central nervous system (CNS) of GMF+/+ (wild type) mice and GMF−/− (GMF-knockout) mice at the peak of EAE induced by immunization with MOG 35-55 peptide. GMF+/+ (Wt) mice developed severe EAE with a maximal mean clinical score of 3.6 ±0.5 by day 16 post immunization, whereas GMF-KO mice showed significantly delayed EAE with an average onset on day 26 pi with reduced mean clinical score of 1.3 ±0.3. Three of fifteen Wt mice as compared to none of GMF-KO mice died of EAE. Encephalitogenic cells from Wt mice transferred to recipient GMF-KO mice caused very mild and with low incidence of EAE. We determined the differences in the expression of cytokines, IFN-γ, TNF-α, IL-1 β, IL-6, IL-4, IL-10, and chemokines, MIP-1, MIP-2, IP-10, MCP-1, GM-CSF mRNA by quantitative real time RT-PCR in brain and spinal cord. Our results demonstrate significantly low levels of pro inflammatory cytokines/chemokines in the CNS of GMF-KO mice and increased expression in Wt mice with EAE. Our data suggest that GMF play a critical role in CNS inflammation.

Cellular and Molecular Neurobiology, Apr 1, 1995

Journal of The American College of Surgeons, Sep 1, 2005

Developmental Biology, Feb 1, 1990

Glia maturation factor beta (GMF-beta) is a 17-kDa growth regulating protein isolated from the br... more Glia maturation factor beta (GMF-beta) is a 17-kDa growth regulating protein isolated from the brain. The effect of bovine GMF-beta on neurons was tested on the neuroblastoma line N18 and the pheochromocytoma line PC12. GMF-beta inhibited the proliferation of N18 cells and promoted their neurite outgrowth, with an increase in neurofilament protein, but had no effect on PC12 cells. This was in contrast to nerve growth factor (NGF) which regulated PC12 but not N18. Acidic fibroblast growth factor (FGF), on the other hand, had a weak effect on PC12 but none on N18. Antisera against GMF-beta and NGF neutralized the biological activity of the corresponding growth factors but showed no cross-neutralization. Fluorescence visualization revealed the binding of GMF-beta to N18 cells but not to PC12 cells; the opposite was true with NGF.

Brain Research, Oct 1, 1994

Neurochemical Research, Dec 7, 2006

Glia maturation factor (GMF), a highly conserved brain-specific protein, isolated, sequenced and ... more Glia maturation factor (GMF), a highly conserved brain-specific protein, isolated, sequenced and cloned in our laboratory. Overexpression of GMF in astrocytes induces the production and secretion of granulocyte-macrophage-colony stimulating factor (GM-CSF), and subsequent immune activation of microglia, expression of several proinflammatory genes including major histocompatibility complex proteins, IL-1b, and MIP-1b, all associated with the development of experimental autoimmune encephalomyelitis (EAE), the animal model for multiple sclerosis. Based on GMF's ability to activate microglia and induce wellestablished proinflammatory mediators, including GM-CSF, we hypothesize that GMF is involved in the pathogenesis of inflammatory disease EAE. In this present investigation, using GMF-deficient mice, we study the role of GMF and how the lack of GMF affects the EAE disease. Our results show a significant decrease in incidence, delay in onset, and reduced severity of EAE in GMF-deficient mice, and support the hypothesis that GMF plays a major role in the pathogenesis of disease.

Brain Research, May 1, 2000

Glial cells play active roles in neuronal survival, as well as neuroprotection against toxic insu... more Glial cells play active roles in neuronal survival, as well as neuroprotection against toxic insult. Recent studies suggest that the brain protein glia maturation factor (GMF) is involved in intracellular signaling in glia. This study investigated whether or not GMF plays a role in the survival-promoting and neuroprotective functions of glia. C6 glioma cells were transfected in vitro with GMF utilizing an adenovirus vector. The transfected cells overexpressed GMF intracellularly, but did not secrete the protein. The conditioned medium (CM) was obtained from the GMF-transfected cells (CM-GMF) and tested on primary neuronal cultures, consisting of cerebellar granule cells (CGC). The CGC cultures were utilized because these cultures have a background level of cell death, and the survival-promoting, i.e. neurotrophic effect, of the CM could be tested. In addition, since CGC cultures are ethanol-sensitive (ethanol enhances neuronal death), the neuroprotective effect of the CM against ethanol-induced cell death was tested also. We demonstrated that the CM-GMF had an enhanced neurotrophic effect as well as an increased neuroprotective effect against ethanol-induced cell death compared to control CM obtained from untransfected C6 cells (CM-Mock) or CM obtained from cells transfected with an unrelated gene (CM-LacZ). Because neurotrophins have trophic and protective effects, we investigated whether GMF-transfection upregulated the expression of neurotrophins in C6 cells. RT-PCR verified that GMFtransfected C6 cells had increased mRNA levels for BDNF and NGF. Immunoblotting corroborated the RT-PCR results and indicated that CM-GMF contained greater concentrations of BDNF and NGF protein compared to CM-Mock and CM-LacZ. A soluble TrkB-IgG fusion protein, which selectively binds BDNF and prevents its binding to the neuronal TrkB receptor, eliminated the neurotrophic effect of CM-GMF; whereas anti-NGF antibody was ineffective in preventing this effect, suggesting that the neurotrophic effect was due to BDNF. On the other hand, both the TrkB-IgG fusion protein and anti-NGF reduced neuroprotection, suggesting that BDNF and NGF both contribute to the neuroprotective effect of CM-GMF. In conclusion, GMF upregulates the expression of BDNF and NGF in C6 cells, and these factors exert neurotrophic and neuroprotective functions on primary neurons.

Brain Research, Nov 1, 1991

Rat sciatic nerves were bilaterally transected and repaired with an entubulation technique. The n... more Rat sciatic nerves were bilaterally transected and repaired with an entubulation technique. The nerve interstump gap was filled with either collagen gel or collagen gel mixed with a putative neurotrophic factor (leupeptin, 4-aminopyridine, lipid angiogenic factor or glia maturation factor fl (GMF-fl)). Six weeks after nerve transection, the myelinated distal stump axons were quantified for each nerve. Only the nerves treated with GMF-fl had significantly more axons than the control side.

Advances in Experimental Medicine and Biology, 1991

ABSTRACT In 1972 this laboratory observed the ability of brain extracts to promote the phenotypic... more ABSTRACT In 1972 this laboratory observed the ability of brain extracts to promote the phenotypic expression of cultured astrocytes and named the active agent “glia maturation factor” (GMF) (Lim et al., 1972, 1973; Lim and Mitsunobu, 1974). Attempts at purifying this factor encountered a number of difficulties. First, it exists in low abundance. Second, the purer the protein is the more unstable it becomes. Third, as purification steps increase, the procedure becomes more and more laborious to carry through. These problems are common to many growth factors and therefore not unique to GMF. However, the purification of GMF was further complicated by the fact that the brain is a source of several other potent growth factors, some of which interfered with the monitoring of GMF.

The FASEB Journal, Dec 1, 1990