BITS Faculty Publications
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Item NEXT Neuroprotective Efficacy of Co-Encapsulated Rosiglitazone and Vorinostat Nanoparticle on Streptozotocin Induced Mice Model of Alzheimer Disease(ACS, 2021-04) Chitkara, Deepak; Taliyan, RajeevAnomalies in brain insulin signaling have been demonstrated to be involved in the pathology of Alzheimer disease (AD). In this context, the neuroprotective efficacy of an insulin sensitizer, rosiglitazone, has been confirmed in our previous study. In the present study, we hypothesize that a combination of an epigenetic modulator, vorinostat, along with rosiglitazone can impart improved gene expression of neurotrophic factors and attenuate biochemical and cellular alteration associated with AD mainly by loading these drugs in a surface modified nanocarrier system for enhanced bioavailability and enhanced therapeutic efficacy. Hence, in this study, rosiglitazone and vorinostat were loaded onto a poloxamer stabilized polymeric nanocarrier system and administered to mice in the intracerebroventricular streptozotocin (3 mg/kg) induced model of AD. Treatment with the free drug combination (rosiglitazone 5 mg/kg, vorinostat 25 mg/kg) for 3 weeks attenuated the behavioral, biochemical, and cellular alterations as compared to either treatment alone (rosiglitazone 10 mg/kg, vorinostat 50 mg/kg). Further, the coencapsulated nanoformulation (rosiglitazone 5 mg/kg, vorinostat 25 mg/kg) exerted better neuroprotective efficacy than the free drug combination as evidenced by improved behavioral outcome, reduced oxidative stress, and elevated levels of neurotrophic factors. In conclusion, the synergistic neuroprotective efficacy of rosiglitazone and vorinostat has been increased through the poloxamer stabilized polymeric nanocarrier system.Item Natural HDAC Inhibitors: Nature’s Answer to the Cancer(NMIMS, 2015) Gaikwad, Anil BhanudasPost translational modifications of histones play a significant role in regulation of physiological and pathological processes in the body. Acetylation is one of the most important chromatin modifying mechanisms being controlled by histone acetyl transferases and histone deacetylases. The histone deacetylases (HDAC) are basically responsible for silencing of gene transcription. Cancer involves silencing of a large number of genes. Inhibition of such gene silencing could possibly lead us to alleviatin or control of cancer progression. Natural HDAC inhibitors, a highly researched topic thus seems an attractive method to conquer the kingdom of cancer and thus prove to be the ‘bull’s eye’ like target for cancer treatmentItem Epigenetic mechanisms in Alzheimer's Disease: Therapeutic potential of Class specific HDAC inhibitors in insulin resistance induced cognitive impairments(JSTAGE, 2018) Taliyan, RajeevNumerous epidemiological studies have demonstrated that insulin resistance contributes to Alzheimer's disease (AD) pathogenesis. However the molecular mechanisms is still remain elusive but various studies have highlighted the epigenetic alterations and involvement of histone deacetylases (HDACs) in insulin resistance and cognitive deficits. In our previous study, we have explored the potential of pan HDAC inhibitor, SAHA, in high fat diet induced insulin resistance. In the present study, we have investigated the potential of isoform specific HDAC inhibitors in insulin resistance induced cognitive impairment in mice. Methods: Mice were subjected to either normal pellet diet (NPD) or high fat diet (HFD) for 8 weeks. HFD fed mice were treated with Class I specific HDAC inhibitor, CI-994 or Class II specific HDAC inhibitor, MC-1568 once daily for 2 weeks. Serum insulin, glucose, triglycerides, total cholesterol and HDL-cholesterol levels were measured. A battery of behavioural parameters was performed to assess cognitive functions. Results: HFD fed mice exhibit characteristic features of insulin resistance, showed a severe deficit in learning and memory. HFD feeding results in significant increase in Amyloid beta1-42 levels as compared with NPD fed mice In contrast, the mice treated with MC-1568 showed significant improvement in insulin resistance condition, marked decrease in Amyloid beta1-42 and significantly ameliorate the HFD induced decrease in BDNF and CREB level as compared to HFD group. Whereas, the mice treated with Class I HDAC inhibitor, CI-994 failed to show any improvement in insulin resistance and cognitive deficits. Conclusion: Based upon these results, it could be suggested that Class II HDAC inhibitors exert better neuroprotective effects as compared to Class I HDAC inhibitors associated with insulin resistant condition.Item Histone deacetylase inhibitor, Valproic acid, ameliorates insulin resistance induced cognitive deficit in mice(Elsevier, 2017-10) Taliyan, RajeevInsulin resistance has been reported as a strong risk factor for Alzheimer’s disease (AD). However the molecular mechanisms of association between these still remain elusive. Recently, elevated level of histone deacetylases (HDACs) and reduced histone acetylation has been reported in AD patients.Thus, targeting HDACs could provide a novel therapeutic strategy for treating these co-morbid condition.Item Transcriptional dysregulation in Huntington’s disease: The role of histone deacetylases(Elsevier, 2015-10) Taliyan, RajeevHuntington’s disease (HD) is a progressive neurological disorder for which there are no disease-modifying treatments. Although, the exact underlying mechanism(s) leading to the neural cell death in HD still remains elusive, the transcriptional dysregulation is a major molecular feature. Recently, the transcriptional activation and repression regulated by chromatin acetylation has been found to be impaired in HD pathology. The acetylation and deacetylation of histone proteins is carried out by opposing actions of histone acetyl-transferases and histone deacetylases (HDACs), respectively. Studies carried out in cell culture, yeast, Drosophila and rodent model(s) have indicated that HDAC inhibitors (HDACIs) might provide useful class of therapeutic agents for HD. Clinical trials have also reported the beneficial effects of HDACIs in patients suffering from HD. Therefore, the development of HDACIs as therapeutics for HD has been vigorously pursued. In this review, we highlight and summarize the putative role of HDACs in HD like pathology and further discuss the potential of HDACIs as new therapeutic avenues for the treatment of HD.Item Epigenetic modifications by inhibiting histone deacetylases reverse memory impairment in insulin resistance induced cognitive deficit in mice(Elsevier, 2016-06) Taliyan, RajeevInsulin resistance has been reported as a strong risk factor for Alzheimer's disease. However, the molecular mechanisms of association between these still remain elusive. Various studies have highlighted the involvement of histone deacetylases (HDACs) in insulin resistance and cognitive deficits. Thus, the present study was designed to investigate the possible neuroprotective role of HDAC inhibitor, suberoylanilide hydroxamic acid (SAHA) in insulin resistance induced cognitive impairment in mice. Mice were subjected to either normal pellet diet (NPD) or high fat diet (HFD) for 8 weeks. HFD fed mice were treated with SAHA at 25 and 50 mg/kg i.p. once daily for 2 weeks. Serum insulin, glucose, triglycerides, total cholesterol and HDL-cholesterol levels were measured. A battery of behavioral parameters was performed to assess cognitive functions. Level of tumour necrosis factor (TNF-α) was measured in hippocampus to assess neuroinflammation. To further explore the molecular mechanisms we measured the histone H3 acetylation and brain derived neurotrophic factor (BDNF) level. HFD fed mice exhibit characteristic features of insulin resistance. These mice also showed a severe deficit in learning and memory along with reduced histone H3 acetylation and BDNF levels. In contrast, the mice treated with SAHA showed significant and dose dependent improvement in insulin resistant condition. These mice also showed improved learning and memory performance. SAHA treatment ameliorates the HFD induced reduction in histone H3 acetylation and BDNF levels. Based upon these results, it could be suggested that HDAC inhibitors exert neuroprotective effects by increasing H3 acetylation and subsequently BDNF level.Item Histone Deacetylase Inhibitor, Trichostatin A, Improves Learning and Memory in High-Fat Diet-Induced Cognitive Deficits in Mice(Springer, 2015) Taliyan, RajeevMetabolic syndrome is increasingly recognized for its effects on cognitive health. Recent studies have highlighted the role of histone deacetylases (HDACs) in metabolic syndrome and cognitive functions. The present study was designed to investigate the possible therapeutic role of a HDAC inhibitor, trichostatin A (TSA), in cognitive impairment associated with metabolic syndrome. To ascertain the mechanisms involved, we fed mice with high-fat diet (HFD) for 4 weeks and examined changes in behavioral and biochemical/oxidative stress markers. Mice subjected to HFD exhibited characteristic features of metabolic disorder, viz., hyperglycemia, hypertriglyceridemia, hypercholesterolemia, and lower high-density lipoprotein (HDL) cholesterol levels. Moreover, these mice showed severe deficits in learning and memory as assessed by the Morris water maze and passive avoidance tasks along with elevated oxidative stress and inflammatory markers in brain homogenates. The observed changes occurred concurrently with reduced brain-derived neurotrophic factor (BDNF). In contrast, the mice treated with the HDAC inhibitor, TSA (0.5 and 1 mg/kg, i.p.), showed a significant and dose-dependent reduction in serum glucose, triglycerides, and total cholesterol along with improvement in HDL-cholesterol levels and learning and memory performance. TSA treatment also results in alleviation of oxidative stress and neuroinflammatory markers. Moreover, TSA significantly augmented the BDNF levels in HFD-fed mice. Thus, based upon these observations, it may be suggested that HDAC inhibition could be a novel therapeutic strategy to combat cognitive impairment associated with metabolic syndrome.Item Histone deacetylase inhibitors: Future therapeutics for insulin resistance and type 2 diabetes(Elsevier, 2016-11) Taliyan, RajeevInsulin resistance is a common feature of obesity and predisposes the affected individuals to a variety of pathologies, including type 2 diabetes mellitus (T2DM), dyslipidemias, hypertension, cardiovascular disease etc. Insulin resistance is the primary cause of T2DM and it occurs many years before the disease onset. Although Thiazolidinediones (TZDs) such as rosiglitazone and pioglitazone are outstanding insulin sensitizers and are in clinical use since 1990s, however, their serious side effects such as heart attack and bladder cancer have limited their utilization. Thus, there is an unmet need to identify a new class of drugs with insulin sensitizing activity and minimal side effects. In the recent years, Histone deacetylase (HDAC) has emerged as a new molecular target in the control of insulin resistance and T2DM. The level of histone acetylation/deacetylation has been found to be altered during insulin resistance and T2DM conditions. HDAC inhibitors have been found to effectively manage insulin resistance and T2DM in various preclinical models and clinical trials. In this review we will focus on various aspects related to regulation of insulin signalling by HDACs and the future scope of HDAC inhibitors as therapeutics for insulin resistance.Item Beneficial effects of sodium butyrate in 6-OHDA induced neurotoxicity and behavioral abnormalities: modulation of histone deacetylase activity(Elsevier, 2015-09) Taliyan, RajeevParkinson’s disease (PD) is the second most common neurodegenerative disorder. Recent studies have investigated the involvement of epigenetic modifications in PD. Histone deacetylase (HDAC) inhibitors have been reported to be beneficial in cognitive and motor deficit states. The present study was designed to investigate the effect of sodium butyrate, a HDAC inhibitor in 6-hydroxydopamine (6-OHDA) – induced experimental PD like symptoms in rats. To produce motor deficit, 6-OHDA was administered unilaterally in the right medial forebrain bundle. Three weeks after 6-OHDA administration, the rats were challenged with apomorphine. Following this, the animals were treated with sodium butyrate (150 and 300 mg/kg i.p.) once daily for 14 days. Movement abnormalities were assessed by battery of behavioral tests. Biochemically, oxidative stress markers, neuroinflammation and dopamine were measured in striatal brain homogenate. Further, to explore the molecular mechanism(s), we measured the level of global H3 histone acetylation and brain derived neurotrophic factor (BDNF). 6-OHDA administration results in significant motor deficit along with reduction in striatal dopamine level. 6-OHDA treated rats showed elevated oxidative stress and neuroinflammatory markers. Treatment with sodium butyrate results in significant attenuation of motor deficits and increased striatal dopamine level. Moreover, sodium butyrate treatment attenuated the oxidative stress and neuroinflammatory markers. These effects occur concurrently with increased global H3 histone acetylation and BDNF levels. Thus, the observed results of the present study are indicative for the therapeutic potential of HDAC inhibitors in PD.Item Progress in discovery and development of natural inhibitors of histone deacetylases (HDACs) as anti-cancer agents(Springer, 2023-08) Jadhav, Hemant R.The study of epigenetic translational modifications had drawn great interest for the last few decades. These processes play a vital role in many diseases and cancer is one of them. Histone acetyltransferase (HAT) and histone deacetylases (HDACs) are key enzymes involved in the acetylation and deacetylation of histones and ultimately in post-translational modifications. Cancer frequently exhibits epigenetic changes, particularly disruption in the expression and activity of HDACs. It includes the capacity to regulate proliferative signalling, circumvent growth inhibitors, escape cell death, enable replicative immortality, promote angiogenesis, stimulate invasion and metastasis, prevent immunological destruction, and genomic instability. The majority of tumours develop and spread as a result of HDAC dysregulation. As a result, HDAC inhibitors (HDACis) were developed, and they today stand as a very promising therapeutic approach. One of the most well-known and efficient therapies for practically all cancer types is chemotherapy. However, the efficiency and safety of treatment are constrained by higher toxicity. The same has been observed with the synthetic HDACi. Natural products, owing to many advantages over synthetic compounds for cancer treatment have always been a choice for therapy. Hence, naturally available molecules are of particular interest for HDAC inhibition and HDAC has drawn the attention of the research fraternity due to their potential to offer a diverse array of chemical structures and bioactive compounds. This diversity opens up new avenues for exploring less toxic HDAC inhibitors to reduce side effects associated with conventional synthetic inhibitors. The review presents comprehensive details on natural product HDACi, their mechanism of action and their biological effects. Moreover, this review provides a brief discussion on the structure activity relationship of selected natural HDAC inhibitors and their analogues which can guide future research to discover selective, more potent HDACi with minimal toxicity.