Understanding the direct connections between metabolism and chromatin dynamics may uncover potential mechanisms involved in the aging process of renal physiology. Despite known differences in incidence and aging renal disease, how biological aging intersects with renal metabolism and epigenetics in a sex-specific context remains poorly understood. Here, we determined the effect of age on renal metabolic pathways and metabolite cofactors of epigenetic modifiers in a sex-specific manner. We measured metabolites in kidney homogenates from young and aged mice by HPLC-TripleTOF (LC–MS). The major metabolic adaptations observed with aging include increased glycolysis, decreased fatty acid oxidation, mitochondrial dysfunction, oxidative stress, and impaired metabolic waste clearance in 24-month-old (aged) mice compared to 4-month-old (young) sex-matched mice. Additionally, we found elevated levels of methylation and acetylation of intermediate metabolites also known as ‘epimetabolites’ in aged mice. Furthermore, age-related alterations were detected in metabolites (acetyl-coenzyme A, flavin adenine dinucleotide, and α-ketoglutarate) that are essential cofactors for the activities of epigenetic enzymes. Sex-specific changes were observed with age such as, significantly enhanced amino acid catabolism and tryptophan metabolism and reduced lysophospholipase activity and ammonia clearance in aged female vs aged male mice. Our results reveal age- and sex-associated alterations in renal metabolic pathways, characterized by an increase in epigenetically modified intermediate metabolites with aging. These findings suggest a complex interplay between renal metabolomics and epigenetics and offer new insights into the mechanisms underlying sex-specific renal physiology of aging kidneys.

The growing population of adults aged 65 years or older has led to more postmenopausal women affected by renal disease, often associated with an increased risk of developing metabolic disorders such as diabetes. High-fat diet (HFD) further worsens health risks by causing systemic metabolic disturbances such as obesity, insulin resistance, and hyperglycemia. Additionally, HFD-driven changes in renal metabolic pathways are strongly linked to impaired kidney function. In our previous study, we demonstrated that treatment with 17β-estradiol (E2) improved metabolic outcomes in ovariectomized (OVX) C57BL/6J mice fed with HFD by reducing adiposity and enhancing glucose homeostasis. In this study, we investigated the hypothesis that HFD-associated metabolic dysfunction in middle-aged OVX mice will lead to altered renal morphology with the onset of renal injury, which is attenuated by E2 treatment. Kidney tissues and urine collected from our previous study were utilized for this work. In brief, female mice, approximately 9 months (M) old, were maintained on either a phytoestrogen-free high-fat diet (HFD; BioServ #F3282) or on a control low-fat diet (LFD; BioServ #F4031) for 12 weeks (12-13M old) prior to ovariectomy. Following OVX, mice were implanted with a silastic tube containing either E2 or vehicle (VEH; cholesterol) and continued their respective diets for an additional 8 to 10 weeks (14-15M old). Renal protein levels of injury markers were measured by Western blot analysis in the four groups (LFD-OVX-VEH, LFD-OVX+E2, HFD-OVX-VEH, HFD-OVX+E2). In HFD-VEH mice, significantly increased body weight (BW; HFD-OVX-VEH: 42.7 ± 0.7 g vs. LFD-OVX-VEH: 31.2 ± 1.2 g, p< 0.01; n =11) and kidney weight (KW; HFD-OVX-VEH: 0.21 ± 0.005 g vs. LFD-OVX-VEH: 0.18 ± 0.007 g, p< 0.01; n =10 and 11) were observed. Estradiol significantly decreased BW in HFD-OVX mice compared with HFD-OVX-VEH mice group (p< 0.01); however, no change was observed in KW in HFD-OVX+E2 vs. HFD-OVX-VEH mice. We assessed renal injury markers in kidney tissues from these mice. No significant change was observed in the renal tubular injury marker, neutrophil gelatinase-associated lipocalin (NGAL), between HFD-fed and LFD-fed mice. However, E2 treatment in HFD-OVX mice exhibited a trend toward reduced NGAL protein levels. Although HFD did not change the tubular injury marker, kidney injury molecule-1 (KIM-1) levels, interestingly, E2 treatment significantly increased KIM-1 and glycosylated KIM-1 levels in both LFD and HFD-fed mice compared with diet-matched vehicle-treated groups. Urinary protein/creatine ratio was comparable in all 4 mice groups. Initial screening of renal morphology (hematoxylin and eosin stain) revealed glomerulomegaly (an adaptive response to fewer nephrons or increased demand on the kidneys, such as from obesity) and increased tubular injury in HFD-fed mice, which was not attenuated by E2 treatment. In summary, our preliminary findings indicate that HFD-fed middle-aged ovariectomized mice with pre-existing metabolic conditions develop renal morphological changes; however, protein levels of injury markers remain unchanged, and E2 treatment does not exert a significant effect. These results suggest that midlife E2 therapy does not improve renal outcomes in obese ovariectomized mice. Funding source: NIH grant R03AG075396 (awarded to PK), COBRE in aging and regenerative medicine (P30GM145498), P01 AG071746 for Project 4 (awarded to AZ), and PPG Cores. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.

The aging kidney represents a complex interplay of genetic, epigenetic, and environmental factors that contribute to systemic pathophysiological changes. Understanding the direct connections between metabolism and chromatin dynamics may uncover potential mechanisms involved in the aging process of renal physiology. We hypothesized that age and sex would differentially regulate renal metabolic pathways and metabolite cofactors of epigenetic modifiers. To test this hypothesis, we utilized kidney tissues from 4-month (M; young), 12M, and 24M (aged)-old female and male C57BL/6JN mice, kindly provided by the NIA Aged Rodent Tissue Bank, and measured metabolites in the renal homogenates by HPLC-TripleTOF (LC-MS). Urine samples of healthy human subjects from young (30-45 years) and older adults (60+ years; post-menopausal females and older males) were analyzed for validation of significant metabolites identified in the mice. Our LC-MS metabolomics analysis reveals significant age-related changes in metabolic pathways in mouse kidney tissues. The major metabolic adaptations observed with aging include increased glycolysis, decreased fatty acid oxidation, mitochondrial dysfunction, oxidative stress, and impaired metabolic waste clearance in both 24M female and male mice compared to 4M sex-matched mice. Additionally, we found elevated levels of methylation and acetylation of intermediate metabolites in aged mice compared to their younger counterparts. Sex-specific changes were observed with age such as, significantly enhanced amino acid clearance and tryptophan metabolism and reduced lysophospholipase activity and ammonia clearance in aged female vs aged male mice. Renal pyruvate levels, glycolysis product, decreased with age in 24M female and male mice compared with sex-matched 4M mice (p < 0.01). L-carnitine, an essential enzyme co-factor in β-oxidation of long-chain fatty acids was markedly lower (p < 0.05) in 24M females vs 24M male mice. Anti-aging metabolite, β-hydroxybutyrate (β-HB), an endogenous inhibitor of epigenetic enzyme, histone deacetylases, was significantly decreased (p < 0.0001) in 24M male and female mice compared with 4M and 12M sex-matched mice. In contrast, anti-aging metabolite, alpha ketoglutarate (a-KG), an intermediate of tricarboxylic acid cycle and glutamine/glutamate metabolism, and an epigenetic cofactor for histone and DNA demethylases was markedly upregulated in aged mice kidney. Translationally, in human urine samples, decreased pyruvate levels were observed in postmenopausal females compared with young females (p < 0.01) and older males (p < 0.05). Urinary L-carnitine levels were significantly lower in postmenopausal females compared with young females (p < 0.05) and higher in older vs young males (p < 0.05). In contrast with mice kidney results, urinary a-KG was reduced in postmenopausal vs young females (p < 0.0001) and older vs young males (p < 0.01). Our results reveal age- and sex-related alterations in renal metabolic pathways, characterized by an increase in epigenetically modified intermediate metabolites with aging. These findings suggest a complex interplay between renal metabolomics and epigenetics and offer new insights into the mechanisms underlying sex-specific renal physiology and the pathophysiology of aging kidneys. Funding source: NIH grant R03AG075396 (awarded to PK) and COBRE in aging and regenerative medicine (P30GM145498). This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.

Understanding the metabolic and epigenetic mechanisms underlying cardiac aging is essential for developing targeted strategies to preserve or restore heart function in older individuals. We hypothesized that age and sex distinctly influence cardiac metabolic pathways and metabolite cofactors associated with histone and protein acetylation and methylation. To test this, we analyzed heart tissues from female and male C57BL/6JN mice at 4 months (4M, young; n=8), 12M (middle-aged; n=8), and 24M (aged; n=8), kindly provided by the NIA Aged Rodent Tissue Bank. Metabolites were quantified using LC-MS (HPLC-TripleTOF) in heart homogenates. Our untargeted metabolomics analysis revealed significant age-related alterations in cardiac metabolism. Key changes in aged mice included dysregulation of glycolysis, the citric acid cycle, ketone body metabolism, fatty acid synthesis/oxidation, glycolipid metabolism, carnitine biosynthesis, and branched-chain amino acid and glycine-serine-alanine pathways compared to sex-matched young mice. Moreover, aged hearts exhibited disrupted levels of metabolites involved in epigenetic regulation, including intermediates of methylation and acetylation. Notably, sex-specific differences emerged with aging: aged females showed increased tryptophan catabolism and homocysteine degradation, while aged males exhibited relatively higher levels of methyl histidine and β-alanine metabolism. Cardiac pyruvate levels, a key glycolytic product, significantly declined with age (p<0.01), while lactate levels increased (p<0.001) in 24M female and male mice compared to their 4M sex-matched counterparts. Cardiac acetyl-CoA levels were markedly elevated in aged mice of both sexes (female: 24M, 84.69 ± 6.6 vs. 4M, 25.06 ± 2.1; male: 24M, 75.6 ± 4.6 vs. 4M, 20.7 ± 2.3; p<0.0001). Conversely, levels of β-hydroxybutyrate, an anti-aging metabolite and endogenous histone deacetylase inhibitor, were significantly reduced in aged mice (p<0.0001 in males; p<0.01 in females). Additionally, α-ketoglutarate, a tricarboxylic acid cycle intermediate and essential epigenetic cofactor for histone and DNA demethylases, was significantly decreased in aged females (24M, 30.2 ± 3.9 vs. 12M, 50.8 ± 1.7; p<0.01). Our results reveal age- and sex-related alterations in cardiac metabolic pathways and metabolite cofactors of epigenetic enzymes, characterized by an increase in epigenetically modified intermediate metabolites with aging.

Polycystic ovary syndrome ( PCOS ) is the most common endocrinopathy in young women. In-utero, children of ~80% of PCOS women in the US are exposed to maternal “hyperandrogenemia and obesity”. It remains unclear whether this exposure affects their cardiovascular ( CV ) health later in life. Using a well-characterized rat model of maternal PCOS, the hyperandrogenemic obese ( HAO ) dams, we previously showed that adult male, not female, offspring ( HAO F1 ) have enhanced blood pressure ( BP ) response to chronic angiotensin ( Ang ) II compared to sex-matched control offspring ( CON F1 ), suggesting their increased risk of later CV disease. Sex steroids have the potential to modulate epigenetics. Histone deacetylase ( HDAC ) and histone acetyltransferase ( HAT ) are markers of epigenetic modifications. HDACs have been shown to promote tumor necrosis factor ( TNF )-α expression and play a role in Ang II-induced hypertension. The present study was designed to test the hypothesis that male HAO F1 have intra-renal activation of HDAC and increased TNF-α that could play a role in their Ang II BP response. Methods: At 4 weeks ( wks ) of age, female SD rats were implanted (s.c.) with either 5α-dihydrotestosterone pellets (7.5 mg/90 d; HAO) or placebo pellets (CON) and mated at 9-12 wks. Offspring were obtained and weaned at 3 wks. Serum testosterone ( T; by LC/MS-MS), renal cortical TNF-α (Bioplex) and renal cortical nuclear HDAC and HAT activities (colorimetric assays) were measured in male offspring (1/litter, 16-24 wks, n=5-9). Results: Male HAO F1 had significantly lower serum T, higher renal cortical HDAC activity and TNF-α (430.2±124 vs 120.6±14 ng/dl, 0.97±0.1 vs 4.51±0.96 OD/min/mg protein and 423.7±47 vs 579.8±47 pg/g tissue, in male CON F1 vs male HAO F1 , respectively, p<0.05), and no change in their renal cortical HAT activity (vs male CON F1 ). Conclusion: Male offspring born to HAO dams develop hypoandrogenemia that is associated with intra-renal activation of HDAC that could be mediating their increased intra-renal inflammation (TNF-α expression) and mediating their exaggerated BP response to Ang II. Future studies will determine the causative relationship between hypoandrogenemia, HDAC activation and TNF-a and their role in the exaggerated pressor response to Ang II in those male offspring. Funding: AHA-24DIVSUP1273026 (JA), NIH-NIGMS P20GM121334 (JFR, NMS), R01HL135089 & R01AG075963 (JFR), AHA-22CDA938320 and 2024 Dean Franklin Award (NMS).

Elucidation of epigenetic mechanism associated with aging renal physiology may reveal potential biomarkers and therapeutic targets for reversing aging renal pathologies. There is a sex difference in the age of onset of renal and cardiac disease, where females are protected against age related changes, including hypertension and fibrosis, until menopause. We hypothesized that sex and age would differentially regulate epigenetic modifications and renal physiology. To test this hypothesis, we examined kidney tissue and serum from 4-month (4M), 12-month (12M), and 24-month (24M)-old male and female C57BL/6JN mice (National Institute of Aging). Renal histone deacetylase (HDAC) and histone acetyltransferase (HAT) activities (ELISA) were significantly higher in all male mice groups compared with age-matched females. However, HAT activity decreased significantly in 24M males compared with 4M males and exhibited sex differences with 24M males having higher (p < 0.05) activity that 24M females. Levels of histone 3 (H3) acetylation at lysine (K) 9 and 27 and methylation at K9 were comparable in all male and female groups. Nonetheless, age and sex differences were observed in H3K27 methylation levels with 24M males having significantly higher (p < 0.05) levels as compared with 24M female mice. Serum creatinine (sCr) levels exhibited significant interaction between age and sex (p < 0.0001). Aging significantly increased sCr levels in 24M mice compared with 4M mice in both sexes. However, sex-differences were evident in sCr levels with 24M female mice having higher levels compared with their age matched male counterparts. Of note, serum levels of kidney injury molecule-1 (KIM-1), a tubule injury biomarker were significantly higher in 24M mice compared with 4M and 12M sex-matched mice (male 24M, 410.1 ± 94.6 vs. 12M, 53.6 ± 17.2 and 4M, 27.9 ± 2.0; pg/ml, p < 0.001; female 24M, 358.3 ± 56.1 vs. 12M, 63.8 ± 13.3 and 4M, 28.2 ± 5.0; pg/ml, p < 0.001). Histones are released in the extracellular space during disease state, act as damage-associated molecular pattern molecules and activate inflammatory pathways. In the serum, circulating histone H3 levels showed significant interaction with age and sex (p < 0.05) and increased significantly with age in both sexes. The data demonstrate that aged female mice exhibited higher levels of serum Cr and KIM-1 whereas aged males have higher KIM-1 levels as compared to sex matched young mice. Sex differences were observed in HDAC and HAT activity with males having higher enzymatic activity as compared to females. These findings will have important implications in age-related renal injury as aging is a primary risk factor for hypertension and related renal disease in men and women. Supported by the NIH grant R03AG075396. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

We determined the epigenetic mechanisms regulating mean arterial pressure (MAP) and renal dysfunction in guanylyl cyclase/natriuretic peptide receptor-A (GC-A/NPRA) gene-targeted mice. The Npr1 (encoding NPRA) gene-targeted mice were treated with class 1 specific histone deacetylase inhibitor (HDACi) mocetinostat (MGCD) to determine the epigenetic changes in a sex-specific manner. Adult male and female Npr1 haplotype (1-copy; Npr1+/-), wild-type (2-copy; Npr1+/+), and gene-duplicated heterozygous (3-copy; Npr1++/+) mice were intraperitoneally injected with MGCD (2 mg/kg) for 14 days. BP, renal function, histopathology, and epigenetic changes were measured. One-copy male mice showed significantly increased MAP, renal dysfunction, and fibrosis than 2-copy and 3-copy mice. Furthermore, HDAC1/2, collagen1alpha-2 (Col1α-2), and alpha smooth muscle actin (α-SMA) were significantly increased in 1-copy mice compared with 2-copy controls. The expression of antifibrotic microRNA-133a was attenuated in 1-copy mice but to a greater extent in males than females. NF-κB was localized at significantly lower levels in cytoplasm than in the nucleus with stronger DNA binding activity in 1-copy mice. MGCD significantly lowered BP, improved creatinine clearance, and repaired renal histopathology. The inhibition of class I HDACs led to a sex-dependent distinctive stimulation of acetylated positive histone marks and inhibition of methylated repressive histone marks in Npr1 1-copy mice; however, it epigenetically lowered MAP, repaired renal fibrosis, and proteinuria and suppressed NF-kB differentially in males versus females. Our results suggest a role for epigenetic targets affecting hypertension and renal dysfunction in a sex-specific manner.

Sex differences in renal physiology and pathophysiology are now well established in rodent models and in humans. Epigenetic programming is known to be a critical component of renal injury, as studied mainly in male rodent models; however, not much is known about the impact of biological sex and age on the kidney epigenome. We sought to determine the influence of biological sex and age on renal epigenetic and injury markers, using male and female mice at 4 mo (4M; young), 12 mo (12M), and 24 mo (24M; aged) of age. Females had a significant increase in kidney and body weights and serum creatinine levels and a decrease in serum albumin levels from 4M to 24M of age, whereas minor changes were observed in male mice. Kidney injury molecule-1 levels in serum and renal tissue greatly enhanced from 12M to 24M in both males and females. Circulating histone 3 (H3; damage-associated molecular pattern molecules) levels extensively increased with age; however, males had higher levels than females. Overall, females had markedly high histone acetyltransferase (HAT) activity than age-matched males. Aged mice had decreased HAT activity and increased histone deacetylase activity than sex-matched 12M mice. Aged females had substantially decreased renal H3 methylation at lysine 9 and 27 and histone methyltransferase (HMT) activity than aged male mice. Antiaging protein Klotho levels were significantly higher in young males than age-matched females and decreased substantially with age in males, whereas epigenetic repressor of Klotho, trimethylated H3K27, and its HMT enzyme, enhancer of zeste homolog 2, increased consistently with age in both sexes. Moreover, nuclear translocation and activity of proinflammatory transcription factor nuclear factor-κB (p65) were significantly higher in aged mice. Taken together, our data suggest that renal aging lies in a range between normal and diseased kidneys but may differ between female and male mice, highlighting sex-related differences in the aging process.NEW & NOTEWORTHY Although there is evidence of sex-specific differences in kidney diseases, most preclinical studies have used male rodent models. The clinical data on renal injury have typically not been stratified by sex. Our findings provide convincing evidence of sex-specific differences in age-regulated epigenetic alterations and renal injury markers. This study highlights the importance of including both sexes for better realization of underlying sex differences in signaling mechanisms of aging-related renal pathophysiology.

Understanding epigenetic mechanisms associated with aging might reveal potential biomarkers for aging as well as therapeutic targets for reversing or ameliorating aging pathologies, including cardiovascular disease. There is a sex difference in the age of onset of cardiovascular disease, where females are protected against age related changes, including hypertension and fibrosis, until menopause. We hypothesized that epigenetic mechanisms would be differentially regulated in a sex and age dependent manner, with changes in the older females reflecting the loss of estrogen with aging. To test this hypothesis, we examined heart tissue from 4-month (4M), 12-month (12M), and 24-month (24M)-old male and female C57BL/6JN mice (National Institute of Aging). Surprisingly histone deacetylase (HDAC) activity (ELISA) was significantly higher in all female mice than in age-matched males (4M, female 5.2 ± 0.6 vs male 2.8 vs 0.5; 12M, female 4.2 ± 0.4 vs male 1.3 ± 0.2; 24M, female 8.1 ± 0.6 vs male 2.3 ± 0.4; ng/min/mg protein; p < 0.05). In females age increased HDAC activity (35% increase 24M v 4M; p < 0.05). Western blot analysis revealed that expression levels of profibrotic class I HDACs were significantly higher in 12M and 24M old female mice (HDAC1, 52% and 48%, p < 0.05 and HDAC2, 52% and 79%, p < 0.05), respectively, as compared with age-matched males. However, histone acetyltransferase activity was comparable in all male and female groups as was histone 3 (H3) acetylation at lysine 9 and 27. Levels of circulating histones were determined in the serum. Histones are released in the extracellular space during disease state, act as damage-associated molecular pattern molecules and activate inflammatory pathways. Circulating H3 levels in serum increased significantly with age in both sexes (male 12M, 17.1 ± 1.4; and 24M, 21.4 ± 0.8 vs. 4M, 4.0 ± 0.6; ng/ml, p < 0.05; female 12M, 13.8 ± 2.1 and 24M, 17.4 ± 1.4 vs. 4M, 7.2 ± 1.0 p < 0.05). The data demonstrate the effect of age and sex in heart tissues with aged female mice exhibiting higher levels of profibrotic epigenetic enzymes compared to males. These findings will have important implications in age-related cardiac injury as aging is a primary risk factor for hypertension and related heart disease in men and women.

Pre-intervention period of July 2019-June 2020:-28 outpatient PCIs were performed -6 our of 28 (21%) patients who underwent PCI were discharged on the same procedure day Post-intervention period of July 2020-June 2021:-51 outpatient PCIs were performed -27 our of 51 (53%) patients who underwent PCI were discharged on the same procedure day Post-intervention period July 2021-June 2022 -33 outpatient PCIs were performed -28 out of 33 (85%) patients who underwent PCI were discharged on the same procedure day Chi-square analysis was performed and the difference in same day discharges between the first year and the two additional years following intervention was statistically significant, p = <0.01.Conclusions: Our study shows that physician and catheterization laboratory staff education regarding "high-risk" procedural and patient characteristics, along with appropriate resources utilization had an impact on disposition and significantly reduced the number of postprocedural hospital admissions.

Cardiac hormones act on the regulation of blood pressure (BP) and cardiovascular homeostasis. These hormones include atrial and brain natriuretic peptides (ANP, BNP) and activate natriuretic peptide receptor-A (NPRA), which enhance natriuresis, diuresis, and vasorelaxation. In this study, we established the ANP-dependent homologous downregulation of NPRA using human embryonic kidney-293 (HEK-293) cells expressing recombinant receptor and MA-10 cells harboring native endogenous NPRA. The prolonged pretreatment of cells with ANP caused a time- and dose-dependent decrease in 125I-ANP binding, Guanylyl cyclase (GC) activity of receptor, and intracellular accumulation of cGMP leading to downregulation of NPRA. Treatment with ANP (100 nM) for 12 h led to an 80% decrease in 125I-ANP binding to its receptor, and BNP decreased it by 62%. Neither 100 nM c-ANF (truncated ANF) nor C-type natriuretic peptide (CNP) had any effect. ANP (100 nM) treatment also decreased GC activity by 68% and intracellular accumulation cGMP levels by 45%, while the NPRA antagonist A71915 (1 µM) almost completely blocked ANP-dependent downregulation of NPRA. Treatment with the protein kinase G (PKG) stimulator 8-(4-chlorophenylthio)-cGMP (CPT-cGMP) (1 µM) caused a significant increase in 125I-ANP binding, whereas the PKG inhibitor KT 5823 (1 µM) potentiated the effect of ANP on the downregulation of NPRA. The transfection of miR-128 significantly reduced NPRA protein levels by threefold compared to control cells. These results suggest that ligand-dependent mechanisms play important roles in the downregulation of NPRA in target cells.

The objective of this study was to investigate the effect of class I-specific histone deacetylase inhibitor, mocetinostat (MGCD0103; MGCD) in the regulation of epigenetic mechanisms and renal pathology and disorders in Npr1 (coding for natriuretic peptide receptor A; NPRA) gene-disrupted haplotype mice. Male and female Npr1 gene-disrupted (1-copy; +/- ), wild-type (2-copy; +/+ ) and gene-duplicated (3-copy; ++/+) mice were administrated with MGCD (2 mg/kg) by intraperitoneal injection at alternate days for 2-weeks. The renal NPRA protein levels and guanylyl cyclase (GC) activity were significantly lower in 1-copy mice and higher in 3-copy than in 2-copy mice; however, MGCD increased NPRA protein levels and GC activity. The vehicle-treated females showed lower SBP than male mice, whereas both sexes of 1-copy mice had higher SBPs, and 3-copy mice had lower SBPs as compared with 2-copy mice. Treatment with MGCD distinctly reduced SBP in male (1-copy, Δ-21±2.0 mmHg, p<0.001; 2-copy, Δ-5±0.6 mmHg, p<0.01; and 3-copy, Δ-4±0.5 mmHg, p<0.05) and female mice (1-copy, Δ-17±2.1 mmHg, p<0.01; 2-copy, Δ-3±0.5 mmHg, p<0.01; and 3-copy, Δ-3±0.8 mmHg). Hematoxylin and eosin staining showed pronounced renal morphological damages in 1-copy male than female mice as compared to 2-copy and 3-copy mice. One-copy male mice exhibited a greater degree of mesangial matrix expansion and interstitial nephritis as compared with 2-copy and 3-copy mice, which was significantly (p<0.1) decreased with MGCD treatment as compared with vehicle-treated mice. Creatinine clearance was significantly reduced in 1-copy male mice (52%; p<0.05) than female mice (35%; p<0.05) compared with 2-copy mice. The renal HDAC activity and HDAC1 and 2 protein levels in 1-copy male mice were significantly (p<0.05) higher than female mice as compared with 2-copy mice. MGCD markedly increased acetylation of histone marks (H3-K9, H3-K27, and H3-K18) and greatly reduced the renal pathologies as compared with controls. The present results demonstrate that MGCD upregulates NPRA activity and repairs renal pathology epigenetically in 1-copy haplotype mice. These findings will have important implications for treatment of hypertension and renal injury in humans in both sexes.

Guanylyl cyclase/natriuretic peptide receptor-A (GC-A/NPRA) is activated by cardiac hormones atrial and brain natriuretic peptides (ANP, BNP) and produces intracellular second messenger cGMP. The physiological actions of ANP/NPRA/cGMP signaling cascade largely include diuresis, natriuresis, vasorelaxation, and organ protection, which maintains blood pressure and opposed renal, cardiac, and vascular injury and remodeling. However, the mechanisms that contribute to the activation of Npr1 (coding for GC-A/NPRA) expression is not well understood. The present study was aimed at understanding the epigenetic mechanisms of DNA methyltransferase (DNMT) inhibitor, 5-Azacytidine (5-Aza)-mediated Npr1 gene transcription. The studies were carried out in mouse mesangial cells (MMCs) and rat thoracic aortic smooth muscle (RTASM) cells, cultured in Dulbecco's modified Eagle's medium containing 10% fetal bovine serum and ITS (insulin, transferrin, and sodium selenite) and treated with 5-Aza for 24 h. Western blot analysis showed that 5-Aza enhanced NPRA protein levels by 5-fold and 7-fold in a dose-dependent manner in MMCs and RTASM cells, respectively, and greatly stimulated intracellular accumulation of cGMP in ANP-treated cells. Treatment with 5-Aza attenuated DNMT activity and repressed DNMT1 protein levels in cells. The MethPrimer search result showed the presence of three cytosine-phosphate-guanine (CpG) islands in the Npr1 full length promoter and 5'-untranslated region (UTR), namely island 1 (-886 to -752, 134 bp), island 2 (-310 to -158, 152 bp), and island 3 (-154 to +310, 464 bp) from the transcription start site. Addition of 5'-UTR encompassing +56 to +359 bp region to the Npr1 promoter constructs, (-1982/+55) and proximal promoter (-356/+55), was inhibitory to Npr1 transcriptional activity, independent of the cell type. Furthermore, treatment with 5-Aza distinctly induced Npr1 promoter activity of the construct -356/5'-UTR by 10-fold in MMCs suggesting that the repressive effect of DNA methylation on Npr1 gene transcription might be via 5'-UTR. The results demonstrate that 5-Aza acts as a potent inducer of Npr1 expression and signaling and provides new insights in the epigenetic control of Npr1, an important player in the control of hypertension and cardiorenal axis. Supported by the NIH grants (HL062147 and DK133833). This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

For social species, including primates, the recognition of dynamic body actions is crucial for survival. However, the detailed neural circuitry underlying this process is currently not well understood. In monkeys, body-selective patches in the visual temporal cortex may contribute to this processing. We propose a physiologically-inspired neural model of the visual recognition of body movements, which combines an existing image-computable model ('ShapeComp') that produces high-dimensional shape vectors of object silhouettes, with a neurodynamical model that encodes dynamic image sequences exploiting sequence-selective neural fields. The model successfully classifies videos of body silhouettes performing different actions. At the population level, the model reproduces characteristics of macaque single-unit responses from the rostral dorsal bank of the Superior Temporal Sulcus (Anterior Medial Upper Body (AMUB) patch). In the presence of time gaps in the stimulus videos, the predictions made by the model match the data from real neurons. The underlying neurodynamics can be analyzed by exploiting the framework of neural field dynamics.

The growing prevalence of hypertension, heart disease, diabetes, and obesity along with an aging population is leading to a higher incidence of renal diseases in society. Chronic kidney disease (CKD) is characterized mainly by persistent inflammation, fibrosis, and gradual loss of renal function leading to renal failure. Sex is a known contributor to the differences in incidence and progression of CKD. Epigenetic programming is an essential regulator of renal physiology and is critically involved in the pathophysiology of renal injury and fibrosis. Epigenetic signaling integrates intrinsic and extrinsic signals onto the genome, and various environmental and hormonal stimuli, including sex hormones, which regulate gene expression and downstream cellular responses. The most extensively studied epigenetic alterations that play a critical role in renal damage include histone modifications and DNA methylation. Notably, these epigenetic alterations are reversible, making them candidates for potential therapeutic targets for the treatment of renal diseases. Here, we will summarize the current knowledge on sex differences in epigenetic modulation of renal fibrosis and inflammation and highlight some possible epigenetic therapeutic strategies for CKD treatment.

Cardiac hormones atrial and brain natriuretic peptides (ANP and BNP) activate guanylyl cyclase/natriuretic peptide receptor-A (GC-A/NPRA) and produces the second messenger cGMP. cGMP activates downstream signaling and biological consequences of ANP/NPRA such as natriuresis, diuresis, vasorelaxation, antimitogenic responses, and cardiac and renal anti-hypertrophic effects. The activity and expression of Npr1 gene (coding for GC-A/NPRA) assessed primarily through ANP-stimulated cGMP production, are mediated by agents, including autoregulation involving natriuretic peptides, osmotic sensors, and other external and internal stimuli, but the hormonal and epigenetic mechanisms mediating Npr1 regulation are not well understood. The objective of present study was to study the effect of Vitamin D (vitD) in the regulation of Npr1 gene transcription and expression via modulation of epigenetic factors. Our bioinformatics study with the murine Npr1promoter has shown presence of 4 vitD response elements (VDRE) in the region -583 to -495 from the transcription start site having perfect and VDRE-like consensus sequence. Npr1promoter activity was determined by transient transfection of Npr1 promoter deletion constructs in cultured rat thoracic aortic smooth muscle cells (RTASMCs) and mouse mesangial cells (MMCs) treated with Vitamin D₃ (1α, 25-dihydroxy; VD3) using dual luciferase assay kit. Luciferase assay demonstrated that VD3 enhances Npr1 promoter activity by more than 5-6-fold in RTASMCs and MMCs in a dose-dependent manner. Western blot and densitometry analysis showed increasing concentrations of VD3 significantly induced NPRA protein levels by 3.5-fold in MMCs and 4.5-fold in RTASMCs and maximum effect was observed at 100 nM. There was 45%-50% inhibition of histone deacetylase (HDAC) activity in presence of VD3 in both cell lines as measured by HDAC activity/inhibition ELISA kit. Moreover, treatment with VD3 reduced class I HDAC enzymes, HDAC1 and HDAC3 protein levels and dose-dependently enhanced acetylation level of histones, H3 at lysine residues 9 and 14 (H3-K9/14 ac) and H4 at lysine residue 12 (H4-K14ac). Treatment of RTASMCs and MMCs with VD3 attenuated DNA methyltransferase (DNMT) activity by 40%-55% as measured by DNMT activity/inhibition ELISA kit. The results demonstrate that VD3 regulate Npr1 gene expression by modulation of histone deacetylases and DNMT activity. The identification of epigenetic targets of vitamin D signaling as a regulator of Npr1gene transcription and protein expression will have important implications in hypertension and cardiovascular regulation.

The visual recognition of body poses and body actions is a fundamental visual function for many social species, especially primates. The detailed underlying neural circuitry is currently not well understood. We propose a physiologically-inspired hierarchical neural model for the recognition of static and moving bodies that attempts to account for electrophysiological and fMRI data. METHODS: Our model combines a feed-forward deep neural network (VGG-19) with a neurodynamical model that reproduces the activation dynamics at the single-cell level in the visual and premotor cortex (Giese and Poggio, 2003). The lower levels of the visual hierarchy were modeled by the layers up to the Conv5.1 layer of VGG-19 (pretrained on ImageNet). These outputs were further processed by a subnetwork consisting of radial basis function units in order to model invariance properties of real cortical neurons in body-selective patches. We propose a recurrent neural network (neural field) (Giese and Poggio, 2003; Fleischer et al., 2013) as the mechanism that accounts for the observation that some body-selective neurons show temporal sequence-selectivity. RESULTS: We tested the model using static images of body poses as well as real videos of macaques and humans performing different actions, which were also used in electrophysiological and fMRI experiments by our consortium. The model successfully recognizes the actions of humans and macaques in the stimuli, including the videos. Like real neurons, the model shows (partial) generalization to silhouette stimuli after being trained on realistic stimuli. It predicts a traveling pulse of activation in populations of sequence-selective body-selective neurons, which is strongly attenuated if the sequential order is reversed. CONCLUSIONS: The model provides an account for several aspects of recently acquired data on the neural representation of bodies in body-selective single units present in body patches in the macaque visual cortex.

Mice lacking Npr1 (encoding guanylyl cyclase/natriuretic peptide receptor‐A; GC‐A/NPRA) exhibit hypertension, kidney disease, and heart failure; however, the epigenetic determinants regulating Npr1 expression and renal function are not well understood. The objective of this study was to investigate the effect of class I‐specific histone deacetylase (HDAC) inhibitor, mocetinostat (MGCD0103; MGCD) on NPRA expression and regulation of mean arterial pressure (MAP) and renal pathology. Adult male and female Npr1 haplotype (1‐copy, Npr1+/‐), wild‐type (2‐copy, Npr1+/+), and gene‐duplicated (3‐copy, Npr1++/+) mice were injected intraperitoneally with MGCD (2 mg/kg) at alternate days for 2‐weeks. Treatment with MGCD significantly enhanced NPRA protein levels and GC activity in male and female mice in all three genotypes. MAP was monitored by telemetry recording. Sex‐differences were observed in MAP as female mice had lower MAP (p < 0.01) than male mice, in all genotypes; whereas, 1‐copy mice exhibited higher MAP than 2‐copy mice. Treatments with MGCD distinctly reduced MAP in 1‐copy and 2‐copy male mice (untreated 1‐copy, 125 ± 3 vs. treated 1‐copy, 108 ± 3 mmHg; p < 0.001; untreated 2‐copy, 98 ± 2 vs. treated 2‐copy, 90 ± 2 mmHg; p < 0.01) and 1‐copy and 2‐copy female mice (untreated 1‐copy, 117 ± 3 vs. treated 1‐copy, 105 ± 2 mmHg; p < 0.001; untreated 2‐copy, 90 ± 2 vs. treated 2‐copy, 84 ± 2 mmHg; p < 0.01). Treatment with MGCD attenuated HDAC activity by 30% in male and 40% in female animals (p < 0.05). The Western blot analyses indicated that 1‐copy male and female mice showed upregulation of alpha‐smooth muscle actin (α‐SMA; 39% and 29%, p < 0.05) and collagen 1 alpha 2 (COL1α2; 49% and 20%, p < 0.05) proteins, respectively, compared with 2‐copy mice. Picrosirius red staining in renal sections showed significant collagen deposition in 1‐copy mice compared with 2‐copy animals of both sexes. MGCD reduced fibrosis by 30%‐45% (p < 0.05) in treated 1‐copy mice compared with untreated control mice in both sexes. The present results indicate that MGCD lowers MAP, and repairs renal fibrosis in male and female mice. These findings will have important implications for treatment of hypertension and renal injury in humans in both genders.