Naheed Amir

Attenuated EAN in TNF-α Deficient Mice Is Associated with an Altered Balance of M1/M2 Macrophages

The role of tumor necrosis factor (TNF)-α and its receptors in neuroautoimmune and neuroinflammatory diseases has been controversial. On the basis of our previous studies, we hereby aimed to further clarify TNF-α’s mechanism of action and to explore the potential role of TNF-α receptor (TNFR)1 as a therapeutic target in experimental autoimmune neuritis (EAN). EAN was induced by immunization with P0 peptide 180–199 in TNF-α knockout (KO) mice and anti-TNFR1 antibodies were used to treat EAN. Particularly, the effects of TNF-α deficiency and TNFR1 blockade on macrophage functions were investigated. The onset of EAN in TNF-α KO mice was markedly later than that in wild type (WT) mice. From day 14 post immunization, the clinical signs of TNF-α KO mice were significantly milder than those of their WT counterparts. Further, we showed that the clinical severity of WT mice treated with anti-TNFR1 antibodies was less severe than that of the control WT mice receiving PBS. Nevertheless, no difference with regard to the clinical signs of EAN or inflammatory infiltration in cauda equina was seen between TNF-α KO and WT mice with EAN after blockade of TNFR1. Although TNF-α deficiency did not alter the proliferation of lymphocytes in response to either antigenic or mitogenic stimuli, it down-regulated the production of interleukin (IL)-12 and nitric oxide (NO), and enhanced the production of IL-10 in macrophages. Increased ratio of regulatory T cells (Tregs) and reduced production of interferon (IFN)-γ in cauda equina infiltrating cells, and elevated levels of IgG2b antibodies against P0 peptide 180–199 in sera were found in TNF-α KO mice with EAN. In conclusion, TNF-α deficiency attenuates EAN via altering the M1/M2 balance of macrophages.

IFN-γ deficiency exacerbates experimental autoimmune neuritis in mice despite a mitigated systemic Th1 immune response

Previous studies have shown that interferon-gamma (IFN-γ) is a proinflammatory cytokine that contributes to the pathogenesis of Guillain-Barré syndrome and its animal model, experimental autoimmune neuritis (EAN). Treatments with anti-IFN-γ antibodies improve clinical outcome in GBS patients and EAN animals and administration of IFN-γ markedly worsens EAN. Paradoxically, the mice deficient in IFN-γ remain susceptible to experimental autoimmune encephalomyelitis, an analogous disease in the central nervous system. These observations raise a question whether IFN-γ might be protective in autoimmune demyelinating diseases. To clarify the role of IFN-γ in the pathogenesis of autoimmune demyelinating diseases, we used P0 protein peptide 180-199 to induce EAN in IFN-γ knockout (KO) mice. After the acute phase of EAN, the clinical signs of IFN-γ KO mice were significantly more severe than those of wild type (WT) controls. After antigenic stimulation, the proliferation of splenic mononuclear cells was significantly higher in IFN-γ KO than in WT mice with EAN. At the peak of EAN, the proportion of interleukin (IL)-17A expressing cells in cauda equina (CE) infiltrating cells, and the levels of IL-17A in sera were elevated in IFN-γ KO mice when compared with their WT counterparts. The proportions of major histocompatibility complex (MHC) II, macrosialin, and IL-12/IL-23p40 expressing cells, relative to total CE infiltrating cells were correspondingly higher in IFN-γ KO than in WT mice with EAN. However, IFN-γ deficiency reduced the production of NO by cultured macrophages in response to proinflammatory stimuli and induced a systemic Th2-oriented immune response. In conclusion, IFN-γ deficiency exacerbates EAN via upregulating Th17 cells despite a mitigated systemic Th1 immune response.

Withania coagulans Fruit Extract Reduces Oxidative Stress and Inflammation in Kidneys of Streptozotocin-Induced Diabetic Rats

The present study was carried out to investigate the changes in oxidative and inflammatory status in streptozotocin-induced diabetic rats kidneys and serum following treatment with Withania coagulans, a popular herb of ethnomedicinal significance. The key markers of oxidative stress and inflammation such as inflammatory cytokines (IL-1β, IL-6, and TNF-α) and immunoregulatory cytokines (IL-4 and IFN-γ) were increased in kidneys along with significant hyperglycemia. However, treatment of four-month diabetic rats with Withania coagulans (10 mg/kg) for 3 weeks significantly attenuated hyperglycemia and reduced the levels of proinflammatory cytokines in kidneys. In addition, Withania coagulans treatment restored the glutathione levels and inhibited lipid peroxidation along with marked reduction in kidney hypertrophy. The present study demonstrates that Withania coagulans corrects hyperglycemia and maintained antioxidant status and reduced the proinflammatory markers in kidneys, which may subsequently reduce the development and progression of renal injury in diabetes. The results of the present study are encouraging for its potential use to delay the onset and progression of diabetic renal complications. However, the translation of therapeutic efficacy in humans requires further studies.

Comparative effect of garlic ( Allium sativum ), onion ( Allium cepa ), and black seed ( Nigella sativa ) on gastric acid secretion and gastric ulcer

Correspondence: salim MA Bastaki Department of Pharmacology, Faculty of Medicine and health sciences, UAe University, PO Box 17666, Al Ain, United Arab emirates Tel +971 3 7137520 Fax +971 3 7672033 email sbastaki@uaeu.ac.ae Abstract: Protective roles of raw and boiled garlic (Allium sativum) and onion (Allium cepa) in comparison with black seed (Nigella sativa) on acidified ethanol-induced gastric ulcers and gastric acid secretion in rats in vivo have been investigated. Raw or boiled Nigella sativa, garlic, or onion significantly inhibited histamine stimulated acid secretion, whereas on basal acid secretion, onion and garlic significantly stimulated secretion but Nigella sativa had no effect. Raw Nigella sativa and garlic showed a significant decrease in the ulcer index when compared with the control at all doses (0.25 g/kg, 0.5 g/kg, and 1 g/kg) tested, whereas onion-only, at doses of 0.5 g/kg and 1 g/kg, significantly reduced the ulcer index. Boiled Nigella sativa showed equal potency to raw Nigella sativa in decreasing ulcer index, but boiled garlic and onion showed reduced potency. The results of this study demonstrate the protective role of raw Nigella sativa, garlic, and onion against ethanol-induced gastric ulcers and gastric acid secretion. Boiling did not affect the protective effect of Nigella sativa on gastric ulcers.

Garcinia kola aqueous suspension prevents cerebellar neurodegeneration in long-term diabetic rat – a type 1 diabetes mellitus model

ETHNOPHARMACOLOGICAL RELEVANCE The development of compounds able to improve metabolic syndrome and mitigate complications caused by inappropriate glycemic control in type 1 diabetes mellitus is challenging. The medicinal plant with established hypoglycemic properties Garcinia kola Heckel might have the potential to mitigate diabetes mellitus metabolic syndrome and complications. AIM OF THE STUDY We have investigated the neuroprotective properties of a suspension of G. kola seeds in long-term type 1 diabetes mellitus rat model. MATERIALS AND METHODS Wistar rats, made diabetic by single injection of streptozotocin were monitored for 8 months. Then, they were administered with distilled water or G. kola oral aqueous suspension daily for 30 days. Body weight and glycemia were determined before and after treatment. After sacrifice, cerebella were dissected out and processed for stereological quantification of Purkinje cells. Histopathological and immunohistochemical analyses of markers of neuroinflammation and neurodegeneration were performed. RESULTS Purkinje cell counts were significantly increased, and histopathological signs of apoptosis and neuroinflammation decreased, in diabetic animals treated with G. kola compared to diabetic rats given distilled water. Glycemia was also markedly improved and body weight restored to non-diabetic control values, following G. kola treatment. CONCLUSIONS These results suggest that G. kola treatment improved the general condition of long-term diabetic rats and protected Purkinje cells partly by improving the systemic glycemia and mitigating neuroinflammation.

Studies on N-Acetyltransferase (NAT2) Genotype Relationships in Emiratis: Confirmation of the Existence of Phenotype Variation among Slow Acetylators: N-Acetyltransferase (NAT2) genotype relationships in Emiratis

Individuals with slow N‐acetylation phenotype often experience toxicity from drugs such as isoniazid, sulfonamides, procainamide, and hydralazine, whereas rapid acetylators may not respond to these medications. The highly polymorphic N‐acetyltransferase 2 enzyme encoded by the NAT2 gene is one of the N‐acetylators in humans with a clear impact on the metabolism of a significant number of important drugs. However, there are limited studies on N‐acetylation phenotypes and NAT2 genotypes among Emiratis, and thus this study was carried out to fill this gap.

Genetic polymorphisms of cytochrome P450-1A2 (CYP1A2) among Emiratis.

Cytochrome P450 1A2 (CYP1A2) is one of the CYP450 mixed-function oxidase system that is of clinical importance due to the large number of drug interactions associated with its induction and inhibition. In addition, significant inter-individual differences in the elimination of drugs metabolized by CYP1A2 enzyme have been observed which are largely due to the highly polymorphic nature of CYP1A2 gene. However, there are limited studies on CYP1A2 phenotypes and CYP1A2 genotypes among Emiratis and thus this study was carried out to fill this gap. Five hundred and seventy six non-smoker Emirati subjects were asked to consume a soft drink containing caffeine (a non-toxic and reliable probe for predicting CYP1A2 phenotype) and then provide a buccal swab along with a spot urine sample. Taq-Man Real Time PCR was used to determine the CYP1A2 genotype of each individual. Phenotyping was carried out by analyzing the caffeine metabolites using High Performance Liquid Chromatography (HPLC) analysis. We found that 1.4%, 16.3% and 82.3% of the Emirati subjects were slow, intermediate and rapid CYP1A2 metabolizers, respectively. In addition, we found that 1.4% of the subjects were homozygote for derived alleles while 16.1% were heterozygote and 82.5% were homozygote for the ancestral allele. The genotype frequency of the ancestral allele, CYP1A2*1A/*1A, is the highest in this population, followed by CYP1A2 *1A/*1C and CYP1A2 *1A/*1K genotypes, with frequencies of 0.825, 0.102 and 0.058, respectively. The degree of phenotype/genotype concordance was equal to 81.6%. The CYP1A2*1C/*1C and CYP1A2*3/*3 genotypes showed significantly the lowest enzyme phenotypic activity. The frequency of slow activity CYP1A2 enzyme alleles is very low among Emiratis which correlates with the presence of low frequencies of derived alleles in CYP1A2 gene.

Possible protecting role of TNF-α in kainic acid-induced neurotoxicity via down-regulation of NFκB signaling pathway.

We have shown previously, that mice lacking tumor necrosis factor-α (TNF-α) receptor 1 (TNFR1) exhibit greater hippocampal neurodegeneration, suggesting that TNFR1 may be protective in kainic acid (KA)-induced neurotoxicity. Here, we aim to clarify the role of TNF-α in neurodegenerative disorders and to elucidate its potential signaling pathways. TNF-α knockout (KO) mice and wild-type (WT) mice were treated with KA intranasally and, seizure severity measures obtained, Behavioral tests, including Elevated Plus-Maze™, open-field, Y-maze were also performed. Five days following KA treatment, immunohistochemical methods were used to assess neuronal degeneration and glial activation. The production of nitric oxide (NO) and the expression of nuclear factor kappaB (NF-κB) and AKT in the hippocampus were also measured. Compared with WT mice, TNF-α KO mice were more susceptible to KA-induced neurotoxicity, as demonstrated by more severe seizures, measurable behavior changes, greater neuronal degeneration in hippocampus, elevated glial activation and NO production. Additionally, KA-treatment up-regulated the expression of NFκB in TNF-α KO mice to a greater degree than in KA-treated WT mice. We conclude that TNF-α deficiency adversely influences KA-induced neurotoxicity and that TNF-α may play a protective role in KA-induced neurotoxicity via the down-regulation of NFκB signaling pathway.