Browsing by Author "Reddy, Dibbanti HariKrishna"
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Item Apoptosis in Alzheimer�s disease: insight into the signaling pathways and therapeutic avenues(Springer, 2023-04-26T00:00:00) Kumari, Sneha; Dhapola, Rishika; Reddy, Dibbanti HariKrishnaAlzheimer�s disease (AD) is characterized by the accumulation of hyperphosphorylated tau and amyloid-? (A?) protein resulting in synaptic loss and apoptosis. A? and tau deposition trigger apoptotic pathways that result in neuronal death. Apoptosis is considered to be responsible for manifestations associated with AD under pathological conditions. It regulates via extrinsic and intrinsic pathways. It activates various proteins including Bcl-2 family proteins like Bax, Bad, Bid, Bcl-XS, Bcl-XL and caspases comprising of initiator, effector and inflammatory caspases carried out through a cascade of events that finally lead to cell disintegration. The apoptotic elements interact with trophic factors, signaling molecules including Ras-ERK, JNK, GSK-3?, BDNF/TrkB/CREB and PI3K/AKT/mTOR. Ras-ERK signaling is involved in the progression of cell cycle and apoptosis. JNK pathway is also upregulated in AD which results in decreased expression of anti-apoptotic proteins. JAK-STAT triggers caspase-3 mediated apoptosis leading to neurodegeneration. The imbalance between autophagy and apoptosis is regulated by PI3K/Akt/mTOR pathway. GSK-3? is involved in the stimulation of pro-apoptotic factors resulting in dysregulation of apoptosis. Drugs like filgrastim, epigallocatechin gallate, curcumin, nicergoline and minocycline are under development which target these pathways and modulate the disease condition. This study sheds light on apoptotic pathways that are cardinal for neuronal survival and perform crucial role in the occurrence of AD along with the trends in therapeutics targeting apoptosis induced AD. To develop prospective treatments for AD, it is desirable to elucidate potential targets including restoration apoptotic balance, regulation of caspases, Bcl-2 and other crucial proteins involved in apoptosis mediated AD. � 2023, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.Item Implicative role of cytokines in neuroinflammation mediated AD and associated signaling pathways: Current progress in molecular signaling and therapeutics(Elsevier Ireland Ltd, 2023-10-30T00:00:00) Kumari, Sneha; Dhapola, Rishika; Sharma, Prajjwal; Singh, Sunil K.; Reddy, Dibbanti HariKrishnaAlzheimer's Disease (AD) is one of the most devastating age-related disorder causing significant social and economic burden worldwide. It affects the cognitive and social behavior of individuals and characterized by accumulation of A?, phosphorylated tau and cytokines formation. The synthesis and release of cytokines are regulated by specific groups of immune and non-immune cells in response to microglia or astrocyte activation through multiple pathways. Physiologically, microglia assert an anti-inflammatory, quiescent state with minimal cytokine expression and little phagocytic activity in motion to carry out their housekeeping role to eliminate pathogens, aggregated A? and tau protein. However, they develop a phagocytic nature and overexpress cytokine gene modules in response to certain stimuli in AD. Microglia and astrocytes upon chronic activation release an enormous amount of inflammatory cytokines due to interaction with formed A? and neurofibrillary tangle. Gut microbiota dysbiosis also stimulates the release of inflammatory cytokines contributing to AD pathogenesis. In addition, the dysregulation of few signaling pathways significantly influences the development of disease, and the pace of advancement also rises with age. This review sheds light on multiple pathways results into neuroinflammation triggered by activated cytokines worsening AD pathology and making it an appropriate target for AD treatment. This review also included drugs targeting different neuroinflammation pathways under clinical and preclinical studies that are found to be effective in attenuating the disease pathology. � 2023 Elsevier B.V.Item Neuroinflammation in Alzheimer�s Disease: Current Progress in Molecular Signaling and Therapeutics(Springer, 2022-08-20T00:00:00) Thakur, Sujata; Dhapola, Rishika; Sarma, Phulen; Medhi, Bikash; Reddy, Dibbanti HariKrishnaAlzheimer�s disease, a neurodegenerative disease with amyloid beta accumulation as a major hallmark, has become a dire global health concern as there is a lack of clear understanding of the causative agent. It is a major cause of dementia which is increasing exponentially with age. Alzheimer�s disease is marked by tau hyperphosphorylation and amyloid beta accumulation that robs people of their memories. Amyloid beta deposition initiated a spectrum of microglia-activated neuroinflammation, and microglia and astrocyte activation elicited expressions of various inflammatory and anti-inflammatory cytokines. Neuroinflammation is one of the cardinal features of Alzheimer�s disease. Pro-inflammatory cytokine signaling plays multifarious roles in neurodegeneration and neuroprotection. Induction of proinflammatory signaling leads to discharge of immune mediators which affect functions of neurons and cause cell death. Sluggish anti-inflammatory system also contributes to neuroinflammation. Numerous pathways like NF?B, p38 MAPK, Akt/mTOR, caspase, nitric oxide, and COX are involved in triggering brain immune cells like astrocytes and microglia to secrete inflammatory cytokines such as tumor necrosis factor, interleukins, and chemokines and participate in Alzheimer�s disease pathology. PPAR-? agonists tend to boost the phagocytosis of amyloid beta and decrease the inflammatory cytokine IL-1?. Recent findings suggest the cross-link between gut microbiota and neuroinflammation contributing in AD which has been explained in this study. The role of cellular, molecular pathways and involvement of inflammatory mediators in neuroinflammation has also been described; targeting them could be a potential therapeutic strategy for treatment of AD. � 2022, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.Item Recent Advances in Molecular Pathways and Therapeutic Implications Targeting Mitochondrial Dysfunction for Alzheimer�s Disease(Springer, 2021-11-02T00:00:00) Dhapola, Rishika; Sarma, Phulen; Medhi, Bikash; Prakash, Ajay; Reddy, Dibbanti HariKrishnaAlzheimer�s disease (AD) is a neurodegenerative disorder which leads to mental deterioration due to aberrant accretion of misfolded proteins in the brain. According to mitochondrial cascade hypothesis, mitochondrial dysfunction is majorly involved in the pathogenesis of AD. Many drugs targeting mitochondria to treat and prevent AD are in different phases of clinical trials for the evaluation of safety and efficacy as mitochondria are involved in various cellular and neuronal functions. Mitochondrial dynamics is regulated by fission and fusion processes mediated by dynamin-related protein (Drp1). Inner membrane fusion takes place by OPA1 and outer membrane fusion is facilitated by mitofusin1 and mitofusin2 (Mfn1/2). Excessive calcium release also impairs mitochondrial functions; to overcome this, calcium channel blockers like nilvadipine are used. Another process acting as a regulator of mitochondrial function is mitophagy which is involved in the removal of damaged and non-functional mitochondria however this process is also altered in AD due to mutations in Presenilin1 (PS1) and Amyloid Precursor Protein (APP) gene. Mitochondrial dynamics is altered in AD which led to the discovery of various fission protein (like Drp1) inhibitors and drugs that promote fusion. Modulations in AMPK, SIRT1 and Akt pathways can also come out to be better therapeutic strategies as these pathways regulate functions of mitochondria. Oxidative phosphorylation is major generator of Reactive Oxygen Species (ROS) leading to mitochondrial damage; therefore reduction in production of ROS by using antioxidants like MitoQ, Curcumin and Vitamin Eis quiteeffective. � 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.Item Recent advances in molecular pathways and therapeutic implications targeting neuroinflammation for Alzheimer�s disease(Springer Science and Business Media Deutschland GmbH, 2021-11-23T00:00:00) Dhapola, Rishika; Hota, Subhendu Shekhar; Sarma, Phulen; Bhattacharyya, Anusuya; Medhi, Bikash; Reddy, Dibbanti HariKrishnaAlzheimer�s disease (AD) is a major contributor of dementia leading to the degeneration of neurons in the brain with major symptoms like loss of memory and learning. Many evidences suggest the involvement of neuroinflammation in the pathology of AD. Cytokines including TNF-? and IL-6 are also found increasing the BACE1 activity and expression of NF?B resulting in generation of A? in AD brain. Following the interaction of A? with microglia and astrocytes, other inflammatory molecules also get translocated to the site of inflammation by chemotaxis and exaggerate neuroinflammation. Various pathways like NF?B, p38 MAPK, Akt/mTOR, caspase, nitric oxide and COX trigger microglia to release inflammatory cytokines. PPAR? agonists like pioglitazone increases the phagocytosis of A? and reduces inflammatory cytokine IL-1?. Celecoxib and roficoxib like selective COX-2 inhibitors also ameliorate neuroinflammation. Non-selective COX inhibitor indomethacin is also potent inhibitor of inflammatory mediators released from microglia. Mitophagy process is considered quite helpful in reducing inflammation due to microglia as it promotes the phagocytosis of over activated microglial cells and other inflammatory cells. Mitophagy induction is also beneficial in the removal of damaged mitochondria and reduction of infiltration of inflammatory molecules at the site of accumulation of the damaged mitochondria. Targeting these pathways and eventually ameliorating the activation of microglia can mitigate neuroinflammation and come out as a better therapeutic option for the treatment of Alzheimer�s disease. � 2021, The Author(s), under exclusive licence to Springer Nature Switzerland AG.