Publications by authors named "Harshini Chakravarthy"

Sunlight exposure is recognized as a risk factor for the development of age-related macular degeneration (AMD), a common neurodegenerative retinal disease in the elderly. Specifically, the blue light wavelengths within sunlight can negatively impact the physiology of light-sensitive retinal cells, including retinal pigmented epithelium (RPE) and photoreceptors. This review explores blue light-induced retinal degeneration, emphasizing the structural and functional impairments in RPE.

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Pterygium is often associated with chronic ultraviolet (UV) radiation exposure and characterized by the overgrowth of conjunctiva and extracellular matrix (ECM) remodeling. Notably, several studies in the skin have demonstrated that chronic UV radiation can upregulate Granzyme B (GrB) expression and increase ECM degradation. The aim of this study was to compare GrB expression between pterygium and healthy controls and to further link this GrB expression to mast cells.

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Age-related macular degeneration (AMD), a prevalent and progressive degenerative disease of the macula, is the leading cause of blindness in elderly individuals in developed countries. The advanced stages include neovascular AMD (nAMD), characterized by choroidal neovascularization (CNV), leading to subretinal fibrosis and permanent vision loss. Despite the efficacy of anti-vascular endothelial growth factor (VEGF) therapy in stabilizing or improving vision in nAMD, the development of subretinal fibrosis following CNV remains a significant concern.

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Neurotransmitters serve as chemical messengers playing a crucial role in information processing throughout the nervous system, and are essential for healthy physiological and behavioural functions in the body. Neurotransmitter systems are classified as cholinergic, glutamatergic, GABAergic, dopaminergic, serotonergic, histaminergic, or aminergic systems, depending on the type of neurotransmitter secreted by the neuron, allowing effector organs to carry out specific functions by sending nerve impulses. Dysregulation of a neurotransmitter system is typically linked to a specific neurological disorder.

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Since the COVID-19 pandemic started in December 2019, there have been several reports of patients succumbing to neurological complications. Early reports were suggestive of a possibility, while by early 2020 it was clearly evident that although SARS-CoV-2 primarily attacks the respiratory system, the brain is one of the most affected organs post-recovery. Although it may be premature to comment on the long-term effects of COVID-19 in brain, some reliable predictions can be made based on the data currently available.

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Spinal cord injury (SCI) involves damage to any part of the spinal cord which results in temporary or permanent changes in its function. Spinal cord secondary injury activates Rho-associated protein kinase 2 (ROCK2), which is involved in neuroinflammation and cell death by mediating secretion of inflammatory cytokines such as tumor necrosis factor-α (TNF-α), interleukin-1 beta (IL-1β), interleukin-2 (IL-2), and CXC chemokines. Here we evaluated potential inhibitors of ROCK2, Caspase-1, and TNF-α from derived natural compounds and compared them with structural analogues of quadrangularin by molecular docking, followed by correlation using molecular dynamic simulations studies.

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Culture of adult neurons of the central nervous system (CNS) can provide a unique model system to explore neurodegenerative diseases. The CNS includes neurons and glia of the brain, spinal cord and retina. Neurons in the retina have the advantage of being the most accessible cells of the CNS, and can serve as a reliable mirror to the brain.

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Diabetic retinopathy (DR) is a devastating complication of diabetes with a prevalence rate of 35%, and no effective treatment options. Since the most visible clinical features of DR are microvascular irregularities, therapeutic interventions often attempt to reduce microvascular injury, but only after permanent retinal damage has ensued. However, recent data suggests that diabetes initially affects retinal neurons, leading to neurodegeneration as an early occurrence in DR, before onset of the more noticeable vascular abnormalities.

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Background: Diabetic retinopathy is a microvascular disease that results from retinal vascular degeneration and defective repair due to diabetes-induced endothelial progenitor dysfunction.

Objective: Understanding key molecular factors involved in vascular degeneration and repair is paramount for developing effective diabetic retinopathy treatment strategies. We propose that diabetes-induced activation of acid sphingomyelinase (ASM) plays essential role in retinal endothelial and CD34 circulating angiogenic cell (CAC) dysfunction in diabetes.

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Plants commonly respond to stressors by modulating the expression of a large family of calcium binding proteins including isoforms of the ubiquitous signaling protein calmodulin (CaM). The various plant CaM isoforms are thought to differentially regulate the activity of specific target proteins to modulate cellular stress responses. The mechanism(s) behind differential target activation by the plant CaMs is unknown.

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Activation of pro-inflammatory and pro-angiogenic pathways in the retina and the bone marrow contributes to pathogenesis of diabetic retinopathy. We identified miR-15a as key regulator of both pro-inflammatory and pro-angiogenic pathways through direct binding and inhibition of the central enzyme in the sphingolipid metabolism, ASM, and the pro-angiogenic growth factor, VEGF-A. miR-15a was downregulated in diabetic retina and bone marrow cells.

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Diabetic retinopathy is a sight-threatening complication of diabetes, affecting 65% of patients after 10 years of the disease. Diabetic metabolic insult leads to chronic low-grade inflammation, retinal endothelial cell loss and inadequate vascular repair. This is partly due to bone marrow (BM) pathology leading to increased activity of BM-derived pro-inflammatory monocytes and impaired function of BM-derived reparative circulating angiogenic cells (CACs).

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The metabolic insults associated with diabetes lead to low-grade chronic inflammation, retinal endothelial cell damage, and inadequate vascular repair. This is partly due to the increased activation of bone marrow (BM)-derived proinflammatory monocytes infiltrating the retina, and the compromised function of BM-derived reparative circulating angiogenic cells (CACs), which home to sites of endothelial injury and foster vascular repair. We now propose that a metabolic link leading to activated monocytes and dysfunctional CACs in diabetes involves upregulation of a central enzyme of sphingolipid signaling, acid sphingomyelinase (ASM).

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Ataxia telangiectasia mutated (ATM) acts as a defense against a variety of bone marrow (BM) stressors. We hypothesized that ATM loss in BM-hematopoietic stem cells (HSCs) would be detrimental to both HSC function and microvascular repair while sustained ATM would be beneficial in disease models of diabetes. Chronic diabetes represents a condition associated with HSC depletion and inadequate vascular repair.

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Background: Trypanosoma evansi infections, commonly called 'surra', cause significant economic losses to livestock industry. While this infection is mainly restricted to large animals such as camels, donkeys and equines, recent reports indicate their ability to infect humans. There are no World Animal Health Organization (WAHO) prescribed diagnostic tests or vaccines available against this disease and the available drugs show significant toxicity.

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