Biology subjects

Jayarathne, H.

Publications and source records attributed to Jayarathne, H..

3 recordsLinked to original sources

bioRxiv2026

Dose and sex-specificity in Canagliflozin-mediated neuroprotection in aging mice

Canagliflozin (Cana), an SGLT2 inhibitor prescribed for type 2 diabetes, extends median lifespan by 14% in male but not female UM-HET3 mice at 180 ppm, with male-specific neuroprotective effects, despite females accumulating higher drug concentrations in blood and brain. Here, we tested whether reducing the dose to a subclinical level of 60 ppm could provide neuroprotective benefits in females by reducing drug accumulation. Starting treatment at 7 months of age, Cana at 60 ppm improved glucose tolerance in both sexes at 18 months and increased water and food intake, consistent with SGLT2 inhibition, but produced only a transient reduction in fat mass in males after one month on diet, with no sustained effect on body weight in either sex. At 60 ppm, Cana did not improve cognitive function at 18 months or reduce neuroinflammation in males, whereas females showed reduced hippocampal microgliosis and astrogliosis at 24 months. Pharmacokinetic analysis demonstrated that females accumulated 3-to 5-fold higher Cana concentrations than males across brain regions, blood, and liver. Together, these findings demonstrate that neither dose reduction nor greater drug accumulation drives neuroprotective benefit in females, indicating fundamental sex differences in the biological response to SGLT2 inhibition and suggesting that the sex-specific longevity effects of Cana are not simply a matter of dose.

neuroscience↗

bioRxiv2023

Prenatal benzene exposure alters offspring hypothalamic development predisposing to metabolic disease in later life

The hypothalamus is essential in the regulation of metabolism, notably during critical windows of development. An abnormal hormonal and inflammatory milieu during development can trigger persistent changes in the function of hypothalamic circuits, leading to long-lasting effects on the bodys energy homeostasis and metabolism. We recently demonstrated that gestational exposure to benzene at smoking levels induces severe metabolic dysregulation in the offspring. Given the central role of the hypothalamus in metabolic control, we hypothesized that prenatal exposure to benzene impacts hypothalamic development, contributing to the adverse metabolic effects in the offspring. C57BL/6JB dams were exposed to benzene in the inhalation chambers exclusively during pregnancy (from E0.5 to E19). The transcriptome analysis of the offspring hypothalamus at postnatal day 21 (P21) revealed changes in genes related to metabolic regulation, inflammation, and neurodevelopment exclusively in benzene-exposed male offspring. Moreover, the hypothalamus of prenatally benzene-exposed male offspring displayed alterations in orexigenic and anorexigenic projections, impairments in leptin signaling, and increased microgliosis. Additional exposure to benzene during lactation did not promote further microgliosis or astrogliosis in the offspring, while the high-fat diet (HFD) challenge in adulthood exacerbated glucose metabolism and hypothalamic inflammation in benzene-exposed offspring of both sexes. These findings reveal the persistent impact of prenatal benzene exposure on hypothalamic circuits and neuroinflammation, predisposing the offspring to long-lasting metabolic health conditions.

neuroscience↗

bioRxiv2020

Sex hormones underlying 17a-Estradiol effects on neuroinflammation

17--estradiol (17aE2) treatment extends lifespan in male mice and can reduce neuroinflammatory responses in the hypothalamus of 12-month-old males. Although 17aE2 improves longevity in males, female mice are unaffected, suggesting a sexually dimorphic pattern of lifespan regulation. We tested whether the sex-specific effects of 17aE2 on neuroinflammatory responses are mediated by sex hormones and whether hypothalamic changes extend to other brain regions in old age. Manipulating sex hormone levels through gonadectomy, we show that sex-specific effects of 17aE2 on age-associated gliosis are brain region-specific and are partially dependent on gonadal hormone production. 17aE2 treatment started at 4 months of age protected 25-month-old males from hypothalamic inflammation. Castration prior to 17aE2 exposure reduced the effect of 17aE2 on hypothalamic astrogliosis. By contrast, sex-specific changes in microgliosis with 17aE2 were not significantly affected by castration in males. While 17aE2 treatment had no effect of hypothalamic astrocytes or microglia in intact females, ovariectomy significantly increased the occurrence of hypothalamic gliosis evaluated in 25-month-old females, which was partially reduced by 17aE2. In the hippocampus, both male and female gonadally-derived hormones influenced the severity of gliosis and the responsiveness to 17aE2 in a regiondependent manner. The male-specific effects of 17aE2 correlate with changes in hypothalamic ER expression, highlighting a receptor through which 17aE2 could act. The results of this study demonstrate that neuroinflammatory responses to 17aE2 are partially controlled by the presence of sex-specific gonads. Interactions between sex-steroids and neuroinflammation could, therefore, influence late-life health and disease onset, leading to sexual dimorphism in aging.

neuroscience↗