Perigonadal Adipose Tissue Research Articles

Sex-dependent effects of a high fat diet on metabolic disorders, intestinal barrier function and gut microbiota in mouse

Obesity is often associated with sex-dependent metabolic complications, in which altered intestinal barrier function and gut microbiota contribute. We aimed to characterize in mice the sex-dependent effects of a high fat diet on these parameters. Male and female C57BL/6 mice received a standard (SD) or high fat diet (HFD; 60% kcal from fat) during 14 weeks (W14). Body composition, glucose tolerance, insulin sensitivity, intestinal permeability, colonic expression of 44 genes encoding factors involved in inflammatory response and gut barrier function, cecal microbiota, plasma adipokines and white adipose tissue response have been assessed. Both male and female HFD mice exhibited an increase of body weight and fat mass gain and glucose intolerance compared to SD mice. However, only male HFD mice tended to develop insulin resistance associated to increased Tnfα and Ccl2 mRNA expression in perigonadal adipose tissue. By contrast, only female HFD mice showed significant intestinal hyperpermeability that was associated with more markedly altered colonic inflammatory response. Cecal microbiota richness was markedly reduced in both sexes (Observed species) with sex-dependent modifications at the phyla or family level, e.g. decreased relative abundance of Bacillota and Lachnospiraceae in females, increased of Bacteroidaceae in males. Interestingly, some of these microbiota alterations were correlated with peripheral metabolic and inflammatory markers. In conclusions, male and female mice exhibit different responses to a high fat diet with specific changes of gut microbiota, intestinal barrier function, colonic and white adipose tissue inflammation, metabolic markers and body weight gain. The underlying mechanisms should be deciphered in further investigations.

Tissue-specific sex-dependent difference in the metabolism of fatty acid esters of hydroxy fatty acids

Fatty acid esters of hydroxy fatty acids (FAHFAs) are endogenous bioactive lipids known for their anti-inflammatory and anti-diabetic properties. Despite their therapeutic potential, little is known about the sex-specific variations in FAHFA metabolism. This study investigated the role of sex and Androgen Dependent TFPI Regulating Protein (ADTRP), a FAHFA hydrolase. Additionally, tissue-specific differences in FAHFA levels, focusing on the perigonadal white adipose tissue (pgWAT), subcutaneous white adipose tissue (scWAT), brown adipose tissue (BAT), plasma, and liver, were evaluated using metabolomics and lipidomics. We found that female mice exhibited higher FAHFA levels in pgWAT, scWAT, and BAT compared to males. FAHFA levels were inversely related to testosterone and Adtrp mRNA, which showed significantly lower expression in females compared with males in pgWAT and scWAT. However, no significant differences between the sexes were observed in plasma and liver FAHFA levels. Adtrp deletion had minimal impact on both sexes' metabolome and lipidome of pgWAT. However, we discovered higher endogenous levels of triacylglycerol estolides containing FAHFAs, a FAHFA metabolic reservoir, in the pgWAT of female mice. These findings suggest that sex-dependent differences in FAHFA levels occur primarily in specific WAT depots and may modulate local insulin sensitivity in adipocytes, and the role of ADTRP is limited to adipose depots. However, further investigations are warranted to fully comprehend the underlying mechanisms and implications of sex-dependent regulation of human FAHFA metabolism.

Modulatory Effects of Lactobacillus paracasei-Fermented Turmeric on Metabolic Dysregulation and Gut Microbiota in High-Fat Diet-Induced Obesity in Mice.

Turmeric, derived from Curcuma longa, and Lactobacillus paracasei, a lactic acid bacteria, have been studied for their potential antiobesity effects. To date, the antiobesity effects of turmeric fermented with L. paracasei have not been sufficiently investigated. This study was conducted via oral administration of 5% L. paracasei-fermented (FT) and unfermented turmeric (UT) in diet over 16 weeks using high-fat diet (HFD)-induced obese C57BL/6J mice. Results showed that the curcuminoid content of turmeric decreased following fermentation. Furthermore, FT significantly suppressed weight gain and liver and visceral adipose tissue weight and reduced plasma metabolic parameters in both the UT and FT experimental groups. The effects of FT were more noticeable than those of the unfermented form. Moreover, FT downregulated the expression of adipogenesis, lipogenesis, and inflammatory-related protein, but upregulated liver β-oxidation protein SIRT 1, PPARα, and PGC-1α in perigonadal adipose tissue. Additionally, FT ameliorated insulin resistance by activating insulin receptor pathway protein expressions in visceral adipose tissues. FT also modulated gut microbiota composition, particularly in two beneficial bacteria, Akkermansia muciniphila and Desulfovibrio, as well as two short-chain fatty acid-producing bacteria: Muribaculum intestinale and Deltaproteobacteria. Our findings indicate that the modulation effect of FT may be an important pathway for its antiobesity mechanisms.

Activation of NF-κB signaling regulates ovariectomy-induced bone loss and weight gain

Postmenopausal women experience bone loss and weight gain. To date, crosstalk between estrogen receptor signals and nuclear factor-κB (NF-κB) has been reported, and estrogen depletion enhances bone resorption by osteoclasts via NF-κB activation. However, it is unclear when and in which tissues NF-κB is activated after menopause, and how NF-κB acts as a common signaling molecule for postmenopausal weight gain and bone loss. Therefore, we examined the role of NF-κB in bone and energy metabolism following menopause. NF-κB reporter mice, which can be used to measure NF-κB activation in vivo, were ovariectomized (OVX) and the luminescence intensity after OVX increased in the metaphyses of the long bones and perigonadal white adipose tissue, but not in the other tissues. OVX was performed on wild-type (WT) and p65 mutant knock-in (S534A) mice, whose mutation enhances the transcriptional activity of NF-κB. Weight gain with worsening glucose tolerance was significant in S534A mice after OVX compared with those of WT mice. The bone density of the sham group in WT or S534A mice did not change, whereas in the S534A-OVX group it significantly decreased due to the suppression of bone formation and increase in bone marrow adipocytes. Disulfiram, an anti-alcoholic drug, suppressed OVX-induced activation of NF-κB in the metaphyses of long bones and white adipose tissue (WAT), as well as weight gain and bone loss. Overall, the activation of NF-κB in the metaphyses of long bones and WAT after OVX regulates post-OVX weight gain and bone loss.

Spatially Offset Raman Spectroscopy toward In Vivo Assessment of the Adipose Tissue in Cardiometabolic Pathologies.

Spatially offset Raman spectroscopy (SORS) enhanced the capabilities of Raman spectroscopy for the depth-resolved analysis of biological and diffusely scattering samples. This technique offers selective probing of subsurface layers, providing molecular insights without invasive procedures. While SORS has found application in biomedical research, up to now, studies have focused mainly on the detection of mineralization of bones and tissues. Herein, for the first time, SORS is used to assess the soft, organic tissue beneath the skin's surface. In this study, we demonstrate the diagnostic utility of a hand-held SORS device for evaluating the chemical composition of the adipose tissue. We compared perigonadal white adipose tissue (gWAT) in a murine model of atherosclerosis, heart failure, and high-fat diet (HFD) induced obesity. Our results reveal distinct chemical differences in gWAT between HFD-fed and control mice, showcasing the potential of SORS for intravital adipose tissue phenotype characterization. Furthermore, our findings underscore the effectiveness of SORS as a valuable tool for noninvasive assessment of the adipose tissue composition, holding potential diagnostic significance for metabolic disorders.

Characterization of a novel adipose tissue located between abdominal lymph nodes and cervix/prostate in mice.

Perigonadal adipose tissue is a homogeneous white adipose tissue (WAT) in adult male mice without any brown adipose tissue (BAT). However, there are congenital differences in the gonads between male and female mice. Whether heterogeneity existed in perigonadal adipose tissues (ATs) in female mice remains unknown. This study reported a perigonadal brown-like AT located between abdominal lymph nodes and the uterine cervix in female mice, termed lymph node-cervical adipose tissue (LNCAT). Its counterpart, lymph node-prostatic adipose tissue (LNPAT), exhibited white phenotype in adult virgin male mice. When exposed to cold, LNCAT/LNPAT increased uncoupling protein 1 (UCP1) expression via activation of tyrosine hydroxylase (TH), in which abdominal lymph nodes were involved. Interestingly, the UCP1 expression in LNCAT/LNPAT varied under different reproductive stages. The UCP1 expression in LNCAT was upregulated at early pregnancy, declined at midlate pregnancy, and reverted in weaning dams. Mating behavior stimulated LNPAT browning in male mice. We found that androgen but not estrogen or progesterone inhibited UCP1 expression in LNCAT. Androgen administration reversed the castration-induced LNPAT browning. Our results identified a perigonadal brown-like AT in female mice and characterized its UCP1 expression patterns under various conditions.NEW & NOTEWORTHY A novel perigonadal brown-like AT (LNCAT) of female mice was identified. Abdominal lymph nodes were involved in cold-induced browning in this newly discovered adipose tissue. The UCP1 expression in LNCAT/LNPAT was also related to ages, sexes, and reproductive stages, in which androgen acted as an inhibitor role.

Abstract PO5-09-11: Abrupt involution of mouse mammary gland leads to inflammatory systemic changes along with mammary specific metabolic shifts that may enhance risk of breast cancer

Abstract Epidemiological data links higher parity and lack of breastfeeding with increased risk of breast cancer, specifically aggressive triple negative breast cancer (TNBC), and higher mortality rate. Following pregnancy and lactation, breast remodels to near pre-pregnancy stage through apoptotic cell death and adipocyte repopulation process. Long-term breastfeeding and gradual weaning of an infant leads to gradual involution (GI) of the breast, while lack of or abrupt discontinuation of breastfeeding after birth leads to abrupt involution (AI), when rapid and massive cell death takes place. Our studies have shown several precancerous changes, such as increased collagen deposition, inflammation, and hyperplasia in the mammary gland of mice after AI. However, the systemic impact of AI and how this increases risk of breast cancer is yet to be elucidated. Objectives: Our objective is to evaluate the systemic effects that are prompted by the AI mammary gland. We hypothesize that AI leads to marked alteration in lipid metabolism and systemic inflammation that enhances risk for breast cancer. Methods: FVB/n mice (8week old) were paired for breeding. At partum (day 0), dams were randomized to AI or GI cohort and standardized to 6 pups. AI mice had pups removed on day 7 postpartum (ppm) to mimic short-term breastfeeding. For GI mice 3 pups each were removed on day 28 and 31ppm to mimic gradual weaning. Tissues harvested on day 28, 56, and 120 postpartum. Body composition was measured by echo MRI. Glucose tolerance test (GTT) was performed after a 6 hour fast using a 2g/kg glucose intraperitoneal injection. Blood glucose was measured by glucometer. Serum insulin was analyzed by ELISA. HOMA-IR was calculated using blood glucose and serum insulin results. Serum was analyzed using multiplex ELISA by MesoScale Diagnostics. Mammary glands were subjected to untargeted lipidomics. Results: There were no significant differences in body weight, percent body fat or lean mass between AI and GI groups at any time point. However, at day 120 ppm (4 months after partum), we have observed significantly larger amount (1.29-fold increase) of perigonadal adipose tissue (visceral adipose) in AI mice than GI mice (p=0.0112; n=24-38/group). There were no significant differences in blood glucose, serum insulin, HOMA-IR, or GTT results between AI and GI groups at day 120. AI mice had significantly higher levels of cytokines IL-1β (3.1-fold increase, p=0.0417) and KC/GRO (1.5-fold increase, p=0.0196) than GI mice at day 120. At day 28, AI mammary glands had significantly higher amounts of level 3 identified oxidized ceramide containing sphingolipids that were linked to insulin resistance and diabetes. At day 56, GI mammary glands had significantly higher amounts of level 2 and 3 identified metabolites linked to cellular signaling and lipid metabolism. On day 120, there were no significant differences in lipid metabolites between groups. Conclusion: Although histologically GI and AI mammary glands return to near pre-pregnancy state within a month after partum, our data shows specific lipid changes in the AI mammary gland similar to what has been shown in women with TNBC. Furthermore, AI of the mammary gland leads to systemic effects on adiposity and inflammation that could be key to increased breast cancer risk. Further studies along these lines are in progress to understand the whole-body effects of AI and stratify preventive measures for women who cannot breast feed. Significance: Lack of breastfeeding is more prevalent in African American (AA) women and linked to higher risk of developing aggressive TNBC1. Our novel animal models of AI and GI help to link the impact of AI and systemic changes that may enhance breast cancer risk. In particular, we see an increase in visceral adiposity with AI. Understanding this mechanism will help identify strategies to reduce risk in women who are unable or choose not to breastfeed and ultimately help to reduce TNBC and TNBC-related mortality in AA women. Citation Format: Kate Ormiston, Kirti Kaul, Neelam Shinde, Djawed Bennouna, Rachel Kopec, Ramesh Ganju, Sarmila Majumder, Bhuvaneswari Ramaswamy. Abrupt involution of mouse mammary gland leads to inflammatory systemic changes along with mammary specific metabolic shifts that may enhance risk of breast cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-09-11.

Pre-Weaning Overfeeding Promotes Prepubertal Obesity and Evokes Sexual Dysfunction in Young Adult Rats

Obesity in early life can contribute to several health issues in adulthood, including diabetes, high blood pressure, and high cholesterol, and these conditions are associated with sexual dysfunction. Here, we hypothesized that pre-weaning overfeeding can have long lasting effects on body fat distribution and erectile function that will be observed in young adult males. On postnatal day (PND 1), Wistar rats were separated into two groups: normal litter (NL) with 10 pups per dam, or small litter (SL) with 3 pups per dam. Male rats (n = 8-10 per group) were then assessed at two different time points: during the prepubertal stage (PND 40) and in adulthood (PND 120). Erectile function was assessed only after sexual maturation (i.e., PND 120). Body weight, retroperitoneal and perigonadal adipose tissue (fat pad weight/100g of the body) were evaluated. Following euthanasia at PND 120, the corpus cavernosum (CC) was removed to perform functional studies using a strip myograph. Contractile and relaxation responses were evaluated by electrical field stimulation (EFS) and concentration-response curves (CRC) to phenylephrine [Phe, 1nM-30μM, millinewton (mN)] or acetylcholine (Ach 1nM-30μM, % relaxation) were performed. At the prepubertal stage, SL rats had higher body weight (NL 149±3 vs. SL 186±5, g, p<0.05), and increased retroperitoneal (NL 0.17±0.01 vs. SL 0.32±0.03, g/100g, p<0.05) and perigonadal (NL 0.38± 0.02 vs. SL 0.45±0.03, g/100g, p<0.05) adipose tissue. At PND 120, SL group presented increased body weight (NL 534.2.7±13 vs. SL 631.6±10, g, p<0.05), retroperitoneal (NL 1.31±0.11 vs. SL 1.82±0.14, g/100g, p<0.05) and perigonadal (NL 1.74±0.10 vs. SL 2.18±0.15, g/100g, p<0.05) adipose tissue when compared with NL group. The CC of SL rats at PND 120 had increased contraction induced by EFS for all frequencies (1 Hz: NL 0.5 ± 0.2 mN vs. SL 0.9 ± 0.2 mN; 4 Hz: NL 1.2 ± 0.3 mN vs. SL 1.8 ± 0.2 mN; 16 Hz: NL 1.9 ± 0.4 mN vs. SL 3 ± 0.4 mN), whereas the relaxation was decreased in SL (1 Hz: NL 0.77 ± 0.18% vs. SL 0.27 ± 0.09%; 4 Hz: NL 2.48 ± 0.26% vs. SL 1.36 ± 0.41%; 16 Hz: NL 3.06 ± 0.28% vs. SL 2.39 ± 0.53%). CRC showed increased contractile response to Phe (Emax NL 2.3±0.3 vs. SL 3.8± 0.6, mN, p=0.05) and reduced potency of ACh (pEC50 NL 6.4±0.6 vs. SL 4.9±0.7, mN, p=0.1) in the CC of SL. Incubation with indomethacin (10μM) abolished the differences in the contractile response induced by EFS or Phe between SL and NL, suggesting a heightened inflammatory response. Moreover, the CC of SL rats presented increased expression of Phospho-p44/42 MAPK (NL 0.9±0.25 vs. SL 1.3±0.11, p=0.2). Finally, proteome profiler cytokine array of serum samples from SL animals showed increased circulating levels of cytokines and chemokines associated with obesity, aging, and vascular dysfunction. Together, these data suggest that early prepubertal obesity has long-lasting negative implications on sexual function in young adulthood. National Institutes of Health (NIH); American Heart Association (AHA); Fulbright Program. 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.

Early-life thymectomy upregulates proinflammatory chemokine signaling in visceral adipose tissue

We have previously reported that early-life thymectomy (thymex) induces an aged T cell phenotype (i.e. shift from naïve to memory) and subsequent glucose intolerance at 9mo compared to control mice. To determine potential mechanisms of inflammation and glucose intolerance in these mice, we preformed RNA sequencing (RNAseq) on the perigonadal white adipose tissue (pWAT) from thymex and control mice. We hypothesized that thymex mice would exhibit an upregulation of inflammatory genes compared to controls. This study was approved by the IACUC at the University of Texas Arlington. Male C57BL/6 mice underwent thymectomy (n=4-10) at 3wks of age or were left with their thymus intact (control n=4-10). At 9mo of age, mice were euthanized and both pWAT fat pads were dissected. One fat pad was used to determine T cell phenotype via flow cytometry, RNA was extracted from the other fat pat for RNAseq. Group differences were assessed by a students t test; RNAseq p values were adjusted for false discovery rate. RNAseq data is reported as a fold change (normalized to control group gene expression); T cell data reported as mean ± SEM (control vs thymex). There were no statistical differences in the total weight of the pWAT nor the total number of T cells in the fat pads. Gene ontology and KEGG analysis revealed that the adaptive immune response, chemokine signaling, chemokine binding and chemokine receptor binding pathways, all markers of inflammation, were upregulated in the pWAT of thymex mice compared to controls. Further analysis of these pathways revealed that gene expression for the chemokines ccl2 (MCP-1) (3.2 times greater than control; p=<0.01) and ccl5 (RANTES)(2.3 times greater than control; p=<0.01) were significantly upregulated in thymex mice compared to controls. In addition, gene expression for the receptors of these chemokines, ccr2 (1.7 times greater than control; p=<0.01) and ccr5 (4.9 times greater than control; p<0.01) were up-regulated in the pWAT of thymex mice. To determine if these chemokines were actively recruiting T cells to the pWAT, we assessed CCR2 and CCR5 expression on CD4+ (Helper) and CD8+ (Cytotoxic) T cells in the pWAT using flow cytometery. Thymex mice had significantly greater proportions of CD4+ CCR2+ (54.4±4.7%, 72.2±4.3%; p=<0.01) and CCR5+ (57.4±5.1%, 75.4±5.0%; p=0.01) cells compared to controls. Similarly, thymex mice had significantly greater proportions of CD8+ CCR2+ (23.1±4.3%, 43.3±5.4%; p=<0.01) and CCR5+(22.7±5.1%, 41.8±7.1%; p=0.02) cells. These results indicate that early life thymectomy induces upregulation of proinflammatory chemokine signaling in the pWAT. These chemokines appear to recruit T cells and potentially other immune cells to the pWAT, contributing to inflammation and potentially metabolic dysfunction. Funding: AHA 940023, NIH R01AG060395, K01AG061271. 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.

(054) Erectile Dysfunction in Young Adulthood as a Consequence of Early Childhood Obesity

Abstract Introduction Childhood obesity is a worrisome health concern for children and teenagers, as it can contribute to several health issues in adulthood, including diabetes, high blood pressure, and high cholesterol. These conditions have been associated with sexual dysfunction. However, the precise impact of early childhood obesity on erectile function in adult males remains uncertain. Objective We hypothesized that overfeeding during early childhood can have lasting effects on body fat distribution, blood pressure, and erectile function in young adult males. Methods On postnatal day (PND 1), Wistar rats were separated into two groups: normal litter (NL) with 10 pups per dam, or small litter (SL) with 3 pups per dam. Male rats (n = 8-10 per group) were then assessed at two different time points: during the prepubertal stage (PND 40) and in adulthood (PND 120). Erectile function was assessed only after sexual maturation (i.e., on PND 120). Body weight, retroperitoneal and perigonadal adipose tissue (fat pad weight/100g of the body) were evaluated. The mean blood pressure (MBP) was recorded in conscious rats using the indirect tail-cuff method. Following euthanasia at PND 120, the corpus cavernosum was removed to perform functional studies using a strip myograph. Contractile and relaxation responses were evaluated by electrical field stimulation (EFS) and concentration-response curves (CRC) to phenylephrine [Phe, 1nM-30μM, millinewton (mN)] or acetylcholine (Ach 1nM-30μM, % relaxation) were performed. Results At the prepubertal stage, SL rats had higher body weight (NL 149±3 vs. SL 186±5, g, p<0.05), and increased retroperitoneal (NL 0.17±0.01 vs. SL 0.32±0.03, g, p<0.05) and perigonadal (NL 0.38± 0.02 vs. SL 0.45±0.03, g, p<0.05) adipose tissue. At PND 120, SL group presented increased body weight (NL 534±13vs. SL 631.6±10, g/100g, p<0.05), retroperitoneal (NL 1.31±0.11vs. SL 1.82±0.14, g/100g, p<0.05) and perigonadal (NL1.74±0.10vs. SL 2.18±0.15, g/100g, p<0.05) adipose tissue when compared with NL group. Moreover, SL rats presented increased MBP (NL 114.9±0.58 vs SL 120.5±1.2, mmHg). The corpus cavernosum of SL rats at PND 120 had increased contraction induced by EFS for all frequencies (1 Hz: NL 0.5 ± 0.2 mN vs SL 0.9 ± 0.2 mN; 4 Hz: NL 1.2 ± 0.3 mN vs SL 1.8 ± 0.2 mN; 16 Hz: NL 1.9 ± 0.4 mN vs SL 3 ± 0.4 mN), whereas the relaxation was decreased (1 Hz: NL 0.77 ± 0.18% vs SL 0.27 ± 0.09%; 4 Hz: NL 2.48 ± 0.26% vs SL 1.36 ± 0.41%; 16 Hz: NL 3.06 ± 0.28% vs SL 2.39 ± 0.53%). CRC showed increased contractile response to Phe (Emax NL 2.3±0.3 vs. SL 3.8± 0.6, mN, p=0.05) and reduced potency of ACh (pEC50 NL 6.4±0.6 vs SL 4.9±0.7, mN, p=0.1) in the corpus cavernosum of SL. Incubation with indomethacin (10uM) abolished the differences in the contractile response induced by EFS or Phe between SL and NL, suggesting a heightened inflammatory response. Conclusions These data suggest that early childhood obesity has long-lasting negative implications on sexual function in adulthood. Disclosure No.

High-fat diet induced obesity promotes inflammation, oxidative stress, and hepatotoxicity in female FVB/N mice.

Although obesity and subsequent liver injury are increasingly prevalent in women, female mouse models have generally shown resistance to high-fat diet (HFD)-induced obesity. We evaluated control and HFD-fed male and female FVB/N mice, a strain well-suited to transgenic analyses, for phenotypic, histological, and molecular markers related to control of glucose, lipids, and inflammation in serum, liver, and perigonadal white adipose tissues. Unlike many mouse models, HFD-fed FVB/N females gained more perigonadal and mesenteric fat mass and overall body weight than their male counterparts, with increased hepatic expression of lipogenic PPARγ target genes (Cd36, Fsp27, and Fsp27β), oxidative stress genes and protein (Nqo1 and CYP2E1), inflammatory gene (Mip-2), and the pro-fibrotic gene Pai-1, along with increases in malondialdehyde and serum ALT levels. Further, inherent to females (independently of HFD), hepatic antioxidant heme oxygenase-1 (HMOX1, HO-1) protein levels were reduced compared to their male counterparts. In contrast, males may have been relatively protected from HFD-induced oxidative stress and liver injury by elevated mRNA and protein levels of hepatic antioxidants BHMT and Gpx2, increased fatty acid oxidation genes in liver and adipocytes (Pparδ), despite disorganized and inflamed adipocytes. Thus, female FVB/N mice offer a valuable preclinical, genetically malleable model that recapitulates many of the features of diet-induced obesity and liver damage observed in human females.

UNCOUPLING PROTEIN UCP1 EXPRESSION DYNAMICS IN ADIPOSE TISSUES OF THE OUTBRED ICR MICE IN POSTNATAL ONTOGENESIS

Uncoupling protein (UCP1) uncouples mitochondrial respiration from ATP synthesis, resulting in heat production in brown and beige adipocytes. The presence of adipocytes with UCP1 expression in fat depots has been shown to promote metabolic health and provide protection against metabolic disorders. It stimulates interest in studying the age dynamics of UCP1 expression. There are few data available, mainly obtained on the C57Bl/6J mouse line predisposed to obesity and cover either early or late ontogenesis. In our study, for the first time, the expression of the UCP1 protein in the adipose tissues of male ICR mice was studied from the weaning to old age. Interscapular brown adipose tissue (BAT), inguinal and perigonadal white adipose tissue (IWAT and GWAT) of 20-day, 1.5, 6, 18 months mice were collected. UCP1 levels were detected by western-blotting. IWAT UCP1 expression decreased by 2 times between 20 days and 1.5 months. No UCP1 bands on blots from mice older than 1.5 months were observed. In gonadal depot UCP1 was detected only in 30% of the samples from 1.5- and 6‑months old mice, and UCP1 expression level was ten times lower in compare to inguinal depot. No statistically significant changes in UCP1 protein expression were detected in brown adipose tissue. The physiological role of UCP1-expressing cells in GWAT is discussed, as well as a possible relationship between the timing and rate of UCP1 expression decrease during the growth and maturation of reproductive function with the activation of lipogenesis in inguinal adipose tissue.

Acquired Lipodystrophy is Mediated by a Treg Specific Deletion of Helios

Abstract The selective deletion of the transcription factor, Helios, in Regulatory T Cells (Treg) leads to systemic immune activation characterized by a Th1 phenotype, hypergammaglobulinemia, and enhanced germinal center formation. Strikingly, we also observe acquired lipodystrophy, hepatic steatosis, and insulin resistance. Further analysis of the lipodystrophy had revealed a significant lymphocytic infiltrate in both the inguinal and perigonadal adipose tissue, indicating autoimmune mediated destruction of the white adipose tissue (WAT). We show here that the destruction of adipocytes is dependent on CD8 +T cells, as Helios fl/fl× Foxp3Cre mice crossed to B2m deficient mice (lacking Class I MHC) maintain normal adipose tissue volume. Flow cytometry analysis of the infiltrate demonstrates that the destruction of the adipose tissue is mediated by CD8 +T cells through both cytotoxic and Fas-L dependent mechanisms. Preliminary analysis of the adipose tissue Tregs suggests that the Treg fail to acquire or maintain an effector state in the absence of Helios. Thus, Helios deficiency in Treg disrupts immune homeostasis in the adipose tissue, leading to the expansion and activation of CD8 +T cells, the destruction of the tissue and metabolic disease. This work was supported by the Intramural Research Program of NIAID, NIH. This work was supported by the Intramural Research Program of NIAID, NIH.

Distinct PD-1 hiCD4+ T helper cell populations promote CD11c+ T-bet+ B cell expansion in liver and spleen during obesity.

Abstract Obesity is associated with increased deposition of fat in ectopic tissues, such as within the liver and visceral adipose depots, including the omentum and mesentery. Increased visceral fat is an accompanying feature of the metabolic syndrome and is associated with increased end-organ damage in NAFLD. Emerging evidence implicates intrahepatic B cells in the progression of NAFLD, and increased number of proinflammatory B cells have been found in the steatotic livers of HFD-fed mice. Our preliminary studies demonstrate accumulation of inflammatory T-bet+ CD11c+ B cells in the subcutaneous adipose tissue of obese humans and perigonadal adipose tissue of mice on HFD. We now extend those findings into other sites of ectopic fat deposition to determine the obesity-related changes in T-bet+ B cell frequencies in the liver, omenta, and MAT. Flow cytometry identified increased frequencies of T-bet+ B cells in the spleen and livers, but not visceral adipose, of HFD mice. Furthermore, HFD-associated expansion of T-bet+ B cells in the spleen and liver correlated with a rise of T FHand T PHfrequencies, respectively. Future studies will determine the mechanism of tissue-specific T and B cell interactions associated with obesity-induced chronic inflammation. B.T.E. is supported by the NIH award (K12GM111726). T.H. is supported by a postdoctoral fellowship from the Swedish Research Council. This study was supported by NIH R01 AI32798-01A1 and the Voelcker Fund Young Investigator Awards (E.A.L).

Abstract 3991: NOS inhibition enhances docetaxel-mediated anti-tumor effect in obese mice with triple negative breast cancer

Abstract Purpose of the study: To evaluate the role of obesity in tumor progression and tumor microenvironment (TME) dynamic after the inhibition of nitric oxide synthase (NOS) in syngeneic murine models engrafted with triple negative breast cancer (TNBC) tumors. For this study, we wanted to deepen the results of our recently completed phase I/II clinical trial, where treatment with NG-methyl-L-arginine (L-NMMA, a pan-NOS inhibitor) increased the response rate to chemotherapy (docetaxel) in obese metastatic TNBC (ER-/PR-/HER2-) patients to 86% vs. 60% in normal weight individuals. TME analysis from responders revealed a neutrophil phenotype shift from protumor N2 to antitumor N1. We thus hypothesize that combined treatment with L-NMMA and docetaxel enhances antitumor effect by modulating TME in obese mice with TNBC. Experimental procedures: 3-week old female C57BL/6 mice were fed for 10 weeks either with high fat diet (HFD) or normal diet (ND). At week 13, TNBC mouse E0771 tumor cells were injected into the mice mammary fat pad. Once tumors reached 100 mm3, the animals were randomized to four groups: vehicle; docetaxel; L-NMMA; and docetaxel plus L-NMMA treatment. Tumor volume was measured throughout the experiment and growth rate was compared between groups at the end of treatment. Blood, tumor and perigonadal white adipose tissue (pgWAT) were collected. Cytokines and nitrite/nitrate levels (NO2-/NO3-, a NO indicator) were measured from blood and conditioned media (CM) from pgWAT using appropriate kits. Tumor immune cell infiltration was evaluated by immunohistochemistry. GraphPad software was used for statistical analysis and P-values <0.05 were considered to describe statistically significant differences between groups. Results: Tumor growth rate was significantly higher in HFD mice compared to ND mice. Treatment with the docetaxel/L-NMMA combination significantly slowed tumor growth in HFD mice (p=0.015), and showed a similar trend in ND mice (p=0.92) vs. the corresponding vehicle-treated groups. The reduction of tumor growth was significantly higher in HFD mice vs. ND mice (median of differences -2.0, p=0.031). HFD mice presented higher levels of pro-inflammatory cytokines, [IL-1b (p=0.011), IL-6 (p<0.0001) and TNFa (p<0.0001)] vs ND mice in pgWAT CM, as well as increased levels of NO2-/NO3- and expression of iNOS in tumors and in perigonadal adipose tissue. Conclusion: HFD mice had a pro-inflammatory profile with a significantly faster tumor growth and higher expression of iNOS in tumor and adipose tissues. Treatment with the docetaxel/L-NMMA combination resulted in a more significant anti-tumor effect in HFD mice, likely through remodeling of TME. Spatial analysis, including CODEX and immunophenotyping are being conducted to determine the TME influence in obesity associated TNBC and the effect of NOS inhibition. Citation Format: Ivonne Uzair, Kai Sun, Ann Anselme, Wei Qian, Jianying Zhou, Roberto Rosato, Jenny Chang. NOS inhibition enhances docetaxel-mediated anti-tumor effect in obese mice with triple negative breast cancer. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3991.

Senolytic drugs, dasatinib and quercetin, attenuate adipose tissue inflammation, and ameliorate metabolic function in old age.

Aging results in an elevated burden of senescent cells, senescence-associated secretory phenotype (SASP), and tissue infiltration of immune cells contributing to chronic low-grade inflammation and a host of age-related diseases. Recent evidence suggests that the clearance of senescent cells alleviates chronic inflammation and its associated dysfunction and diseases. However, the effect of this intervention on metabolic function in old age remains poorly understood. Here, we demonstrate that dasatinib and quercetin (D&Q) have senolytic effects, reducing age-related increase in senescence-associated β-galactosidase, expression of p16 and p21 gene and P16 protein in perigonadal white adipose tissue (pgWAT; all p≤ 0.04). This treatment also suppressed age-related increase in the expression of a subset of pro-inflammatory SASP genes (mcp1, tnf-α, il-1α, il-1β, il-6, cxcl2, and cxcl10), crown-like structures, abundance of T cells and macrophages in pgWAT (all p≤ 0.04). In the liver and skeletal muscle, we did not find a robust effect of D&Q on senescence and inflammatory SASP markers. Although we did not observe an age-related difference in glucose tolerance, D&Q treatment improved fasting blood glucose (p= 0.001) and glucose tolerance (p= 0.007) in old mice that was concomitant with lower hepatic gluconeogenesis. Additionally, D&Q improved insulin-stimulated suppression of plasma NEFAs (p= 0.01), reduced fed and fasted plasma triglycerides (both p≤ 0.04), and improved systemic lipid tolerance (p= 0.006). Collectively, results from this study suggest that D&Q attenuates adipose tissue inflammation and improves systemic metabolic function in old age. These findings have implications for the development of therapeutic agents to combat metabolic dysfunction and diseases in old age.

MiR-379 mediates insulin resistance and obesity through impaired angiogenesis and adipogenesis regulated by ER stress

We investigated the role of microRNA (miR-379) in the pathogenesis of obesity, adipose tissue dysfunction, and insulin resistance (IR). We used miR-379 knockout (miR-379KO) mice to test whether loss of miR-379 affects high-fat diet (HFD)-induced obesity and IR via dysregulation of key miR-379 targets in adipose tissue. Increases in body weight, hyperinsulinemia, and IR in wild-type (WT)-HFD mice were significantly attenuated in miR-379KO-HFD mice with some sex differences. Relative to control chow-fed mice, in WT-HFD mice, expression of miR-379 and C/EBP homologous protein (Chop) (pro-endoplasmic reticulum [ER] stress) and inflammation in perigonadal white adipose tissue (gWAT) were increased, whereas adipogenic genes and miR-379 target genes (Vegfb and Edem3) were decreased. These changes, as well as key parameters of brown adipose tissue dysfunction (including mitochondrial defects), were significantly attenuated in miR-379KO-HFD mice. WAT from obese human subjects with and without type 2 diabetes showed increased miR-379 and decreased miR-379 target genes. In cultured 3T3L1 pre-adipocytes, miR-379 inhibitors increased miR-379 targets and adipogenic genes. These data suggest that miR-379 plays an important role in HFD-induced obesity through increased adipose inflammation, mitochondrial dysfunction, and ER stress as well as impaired adipogenesis and angiogenesis. miR-379 inhibitors may be developed as novel therapies for obesity and associated complications.

Behavioral defects and downregulation of hippocampal BDNF and nNOS expression in db/db mice did not improved by chronic TGF-β2 treatment.

Epidemiological evidence suggests that there is a link between diabetes and mood disorders, such as depression and anxiety. Although peripheral or central inflammation may explain this link, the molecular mechanisms are not fully understood and few effective treatments for diabetes or mood disorders are available. In the present study, we aimed to determine whether transforming growth factor (TGF)-β2, an anti-inflammatory substance, might represent a potential therapeutic agent for diabetes-related mood behaviors. TGF-β2 expression in the hippocampus is affected by anxiolytic drugs and stress exposure, it is able to cross the blood-brain barrier, and it is as an exercise-induced physiological adipokine that regulates glucose homeostasis. Therefore, we hypothesized that a chronic TGF-β2 infusion would ameliorate diabetes-related glucose intolerance and mood dysregulation. To determine the effects of the chronic administration of TGF-β2 on diabetes, we implanted osmotic pumps containing TGF-β2 into type 2 diabetic mice (db/db mice), and age-matched non-diabetic control wild type mice and db/db mice were infused with vehicle (PBS), for 12 consecutive days. To assess anxiety-like behaviors and glucose homeostasis, the mice underwent elevated plus maze testing and intraperitoneal glucose tolerance testing. Hippocampal and perigonadal visceral white adipose tissue perigonadal white adipose tissue samples were obtained 12 days later. Contrary to our hypothesis, TGF-β2 infusion had no effect on diabetes-related glucose intolerance or diabetes-related behavioral defects, such as inactivity. In db/db mice, the expression of inflammatory markers was high in pgWAT, but not in the hippocampus, and the former was ameliorated by TGF-β2 infusion. The expression of brain-derived neurotrophic factor and neuronal nitric oxide synthase, important regulators of anxiety-like behaviors, was low in db/db mice, but TGF-β2 infusion did not affect their expression. We conclude that although TGF-β2 reduces the expression of pro-inflammatory markers in the adipose tissue of diabetic mice, it does not ameliorate their obesity or mood dysregulation.

Loss of myeloid lipoprotein lipase exacerbates adipose tissue fibrosis with collagen VI deposition and hyperlipidemia in leptin-deficient obese mice

During obesity, tissue macrophages increase in number and become proinflammatory, thereby contributing to metabolic dysfunction. Lipoprotein lipase (LPL), which hydrolyzes triglyceride in lipoproteins, is secreted by macrophages. However, the role of macrophage-derived LPL in adipose tissue remodeling and lipoprotein metabolism is largely unknown. To clarify these issues, we crossed leptin-deficient Lepob/ob mice with mice lacking the Lpl gene in myeloid cells (Lplm−/m−) to generate Lplm−/m−;Lepob/ob mice. We found the weight of perigonadal white adipose tissue (WAT) was increased in Lplm−/m−;Lepob/ob mice compared with Lepob/ob mice due to substantial accumulation of both adipose tissue macrophages and collagen that surrounded necrotic adipocytes. In the fibrotic epidydimal WAT of Lplm−/m−;Lepob/ob mice, we observed an increase in collagen VI and high mobility group box 1, while α-smooth muscle cell actin, a marker of myofibroblasts, was almost undetectable, suggesting that the adipocytes were the major source of the collagens. Furthermore, the adipose tissue macrophages from Lplm−/m−;Lepob/ob mice showed increased expression of genes related to fibrosis and inflammation. In addition, we determined Lplm−/m−;Lepob/ob mice were more hypertriglyceridemic than Lepob/ob mice. Lplm−/m−;Lepob/ob mice also showed slower weight gain than Lepob/ob mice, which was primarily due to reduced food intake. In conclusion, we discovered that the loss of myeloid Lpl led to extensive fibrosis of perigonadal WAT and hypertriglyceridemia. In addition to illustrating an important role of macrophage LPL in regulation of circulating triglyceride levels, these data show that macrophage LPL protects against fibrosis in obese adipose tissues.

Set7 Deletion Prevents Glucose Intolerance and Improves the Recovery of Cardiac Function After Ischemia and Reperfusion in Obese Female Mice.

An obesogenic diet (high fat and sugar, low fiber) is associated with an increased risk for metabolic and cardiovascular disorders. Previous studies have demonstrated that epigenetic changes can modify gene transcription and protein function, playing a key role in the development of several diseases. The methyltransferase Set7 methylates histone and non-histone proteins, influencing diverse biological and pathological processes. However, the functional role of Set7 in obesity-associated metabolic and cardiovascular complications is unknown. Wild type and Set7 knockout female mice were fed a normal diet or an obesogenic diet for 12 weeks. Body weight gain and glucose tolerance were measured. The 3T3-L1 cells were used to determine the role of Set7 in white adipogenic differentiation. Cardiac morphology and function were evaluated by histology and echocardiography. An ex vivo Langendorff perfusion system was used to model cardiac ischemia/reperfusion (I/R). Here, we report that Set7 protein levels were enhanced in the heart and perigonadal adipose tissue (PAT) of female mice fed an obesogenic diet. Significantly, loss of Set7 prevented obesogenic diet-induced glucose intolerance in female mice although it did not affect the obesogenic diet-induced increase in body weight gain and adiposity in these animals, nor did Set7 inhibition change white adipogenic differentiation in vitro. In addition, loss of Set7 prevented the compromised cardiac functional recovery following ischemia and reperfusion (I/R) injury in obesogenic diet-fed female mice; however, deletion of Set7 did not influence obesogenic diet-induced cardiac hypertrophy nor the hemodynamic and echocardiographic parameters. These data indicate that Set7 plays a key role in obesogenic diet-induced glucose intolerance and compromised myocardial functional recovery after I/R in obese female mice.