👤 Karthikeyan Ramamurthy

Obesity is a chronic disease caused by the accumulation of cholesterol, which often requires long-term management strategies, such as dietary changes, increased physical activity, and psychological support. Obesity associated neurobehavioral disorders are a growing global health concern, emphasizing the need for innovative therapeutic strategies. Our study evaluates the therapeutic efficacy of (Z)-1-(furan-2-yl)-N-(4-(2-nitrophenyl)-6-(p-tolyl)pyrimidin-2-yl)methanimine referred as BN3 derivative, in treating high-fat diet-induced metabolic and behavioral dysfunctions in a zebrafish model. The research focused on reducing oxidative stress, lipid accumulation, and neurobehavioral deficits, which are closely linked to obesity-related metabolic stress. In this study, zebrafish were divided into five separate experimental groups: control group, model of obesity caused by high-fat diets, BN3 (50 µM and 100 µM), and Positive Control (PC) Group treated with Lovastatin 100 µM. Initially, fish were fed a high-fat diet for 14 days and followed by 30 days of exercise and simultaneously administering BN3 treatments via oral gavage. Assessment of biochemical, histopathology, gene expression, and behavioral were carried out. The results indicated that BN3 treatment significantly decreased oxidative stress levels by enhancing the activity of four antioxidant enzymes (Superoxide Dismutase, Catalase, Glutathione Transferase and Glutathione Peroxidase). BN3 also decreased lipid accumulation as evidenced through histological staining analysis, and total cholesterol estimation. BN3 enhanced locomotion, social interaction, and exploratory behaviors, and reduced anxiety, with the 100 µM treatment group exhibiting the same results as the PC. Gene expression analysis indicates that BN3 is modulating pparγ, fas, pik3cd, src-3, and bdnf pathways (metabolic and neuroinflammation pathways). BN3 impacted these multiple metabolic and neurobehavioral impairments associated with obesity through a multisite treatment approach. BN3 demonstrates significant therapeutic potential, assuring further studies to explore its long-term safety, pharmacokinetics, and translational application in managing obesity and related disorders. Show less

We profile genome-wide histone 3 lysine 27 acetylation (H3K27ac) of 3 major brain cell types from hippocampus and dorsolateral prefrontal cortex (dlPFC) of subjects with and without Alzheimer's Disease (AD). We confirm that single nucleotide polymorphisms (SNPs) associated with late onset AD (LOAD) show a strong tendency to reside in microglia-specific gene regulatory elements. Despite this significant colocalization, we find that microglia harbor more acetylation changes associated with age than with amyloid-β (Aβ) load. In contrast, we detect that an oligodendrocyte-enriched glial (OEG) population contains the majority of differentially acetylated peaks associated with Aβ load. These differential peaks reside near both early onset risk genes ( Show less

Bardet-Biedl syndrome (BBS) is an autosomal recessive ciliopathy characterized by developmental abnormalities and vision loss. To date, mutations in 21 genes have been linked to BBS. The products of eight of these BBS genes form a stable octameric complex termed the BBSome. Mutations in BBS8, a component of the BBSome, cause early vision loss, but the role of BBS8 in supporting vision is not known. To understand the mechanisms by which BBS8 supports rod and cone photoreceptor function, we generated animal models lacking BBS8. The loss of BBS8 protein led to concomitant decrease in the levels of BBSome subunits, BBS2 and BBS5 and increase in the levels of the BBS1 and BBS4 subunits. BBS8 ablation was associated with severe reduction of rod and cone photoreceptor function and progressive degeneration of each photoreceptor subtype. We observed disorganized and shortened photoreceptor outer segments (OS) at post-natal day 10 as the OS elaborates. Interestingly, loss of BBS8 led to changes in the distribution of photoreceptor axonemal proteins and hyper-acetylation of ciliary microtubules. In contrast to properly localized phototransduction machinery, we observed OS accumulation of syntaxin3, a protein normally found in the cytoplasm and the synaptic termini. In conclusion, our studies demonstrate the requirement for BBS8 in early development and elaboration of ciliated photoreceptor OS, explaining the need for BBS8 in normal vision. The findings from our study also imply that early targeting of both rods and cones in BBS8 patients is crucial for successful restoration of vision. Show less

CTRP4 is a unique member of the C1q family, possessing two tandem globular C1q domains. Its physiological function is poorly defined. Here, we show that CTRP4 is an evolutionarily conserved, ∼34-kDa secretory protein expressed in the brain. In human, mouse, and zebrafish brain, CTRP4 expression begins early in development and is widespread in the central nervous system. Neurons, but not astrocytes, express and secrete CTRP4, and secreted proteins form higher-order oligomeric complexes. CTRP4 is also produced by peripheral tissues and circulates in blood. Its serum levels are increased in leptin-deficient obese (ob/ob) mice. Functional studies suggest that CTRP4 acts centrally to modulate energy metabolism. Refeeding following an overnight fast induced the expression of CTRP4 in the hypothalamus. Central administration of recombinant protein suppressed food intake and altered the whole-body energy balance in both chow-fed and high-fat diet-fed mice. Suppression of food intake by CTRP4 is correlated with a decreased expression of orexigenic neuropeptide (Npy and Agrp) genes in the hypothalamus. These results establish CTRP4 as a novel nutrient-responsive central regulator of food intake and energy balance. Show less