Liver Androgen Receptor Knockout Improved High-fat Diet Induced Glucose Dysregulation in Female Mice But Not Male Mice.

Previous research has indicated that liver androgen receptors may play a role in modulating disease. This study aims to investigate the pathophysiology of high-fat diet (HFD) induced dysglycemia in male and female liver androgen receptor knockout (LivARKO) mice. We performed metabolic tests on LivARKO female and male mice fed a HFD or a control diet (from Research Diets Inc.) during months 1 or 2 after starting the diet. Additionally, we performed Western blot and quantitative real-time PCR analysis on the livers of the mice to examine intermediates in the insulin signaling pathway. LivARKO-HFD female mice displayed no difference in glucose tolerance compared to female LivARKO-Control (Con) mice, whereas in wild-type female mice, HFD impaired glucose tolerance (IGT). Our data suggests that starting at 1 month, LivARKO may be protecting female mice from HFD-induced metabolic dysfunction. LivARKO-HFD female mice displayed significantly worse insulin sensitivity at 15 minutes compared to LivARKO-Con female mice, but, strangely, LivARKO-HFD female mice had significantly better insulin sensitivity at 60 and 90 minutes compared to LivARKO-Con female mice. Despite protecting against IGT, LivARKO did not protect against HFD-induced hyperinsulinemia in female mice. In contrast to females, male LivARKO-HFD mice displayed impaired glucose tolerance compared to male LivARKO-Con mice. Thus, LivARKO is not protective against HFD-induced glucose metabolic dysfunction in male mice. Lastly, LivARKO-HFD female mice maintained hepatic insulin sensitivity whereas LivARKO-HFD male mice displayed hepatic insulin resistance. These findings suggest that LivARKO delayed the onset of HFD-induced dysglycemia in female mice.

Promoting anti-racism in the legal system: an application of the STYLE framework.

Racism is a critical social problem, and we present a framework to guide professionals in engaging in anti-racist practices. Professionals on the frontlines in psychology and related fields such as social work and public health have a responsibility to engage in anti-racist practices. Part of the professional role must be to advocate for justice through increased proximity to the issues and engagement in anti-oppressive practices. The current discourse introduces a framework through which people working in psychology and other related professions can promote anti-racism work, highlighting the legal system for illustrative purposes. While some professionals in psychology may not have direct experience with the legal system, many of the individuals served by psychologists do (e.g., clients/patients, students, community members). Our framework is represented by the acronym STYLE (Self-examination, Talk about racism, Yield time to anti-racism work, Learn about structural racism, Evaluate policies and practices). The goal of STYLE is to expand anti-racism science and practice within psychology and related fields. We describe new roles for professionals in dismantling health inequities and offer specific pathways to develop critical partnerships toward this aim. STYLE explicitly encourages active, intentional involvement of affected community members in the development and evaluation of approaches to health services. To achieve equity and to promote individual and organizational growth in anti-racism and ultimately anti-oppression work, professionals must focus on changing their STYLE.

Juneteenth in STEMM and the barriers to equitable science.

We are 52 Black scientists. Here, we establish the context of Juneteenth in STEMM and discuss the barriers Black scientists face, the struggles they endure, and the lack of recognition they receive. We review racism's history in science and provide institutional-level solutions to reduce the burdens on Black scientists.

Nonalcoholic Fatty Liver Disease in Women and Girls With Polycystic Ovary Syndrome.

CONTEXT: Nonalcoholic fatty liver disease (NAFLD) describes a spectrum of liver damage due to excessive hepatic lipid accumulation. Recent research has demonstrated a high prevalence of NAFLD in women with polycystic ovary syndrome (PCOS). RESULTS: Strong associations independent of body mass index (BMI) have been found between high androgen levels characteristic of PCOS, as well as insulin resistance, and the presence of NAFLD in these women, suggesting that these factors contribute to liver injury more significantly than obesity. Current studies indicate the occurrence of NAFLD in normal weight women with PCOS in addition to the commonly researched women who are overweight and obese. While the majority of studies address NAFLD in adult, premenopausal women (ages 25-40 years), the occurrence of NAFLD in young and adolescent women has gone largely unaddressed. Research in this field lacks diversity; a majority of studies either focus on populations of White women or are missing demographic information entirely. CONCLUSIONS: Future studies should include larger, more racially and ethnically inclusive populations and particular attention should be paid to how excess androgens and insulin resistance contribute to the increased risk of NAFLD seen in women with PCOS of varying weights, ages, and ethnicities. OBJECTIVE AND METHODS: Here, we review NAFLD in women with PCOS with subsections focused on the impact of hyperandrogenism, BMI, insulin resistance and age. Most notably, we present the most up-to-date racially and ethnically diverse worldwide prevalence of NAFLD in women with PCOS compared with women without PCOS (51.56% vs 29.64%, P < .001, respectively).

Androgen-induced insulin resistance is ameliorated by deletion of hepatic androgen receptor in females.

Androgen excess is one of the most common endocrine disorders of reproductive-aged women, affecting up to 20% of this population. Women with elevated androgens often exhibit hyperinsulinemia and insulin resistance. The mechanisms of how elevated androgens affect metabolic function are not clear. Hyperandrogenemia in a dihydrotestosterone (DHT)-treated female mouse model induces whole body insulin resistance possibly through activation of the hepatic androgen receptor (AR). We investigated the role of hepatocyte AR in hyperandrogenemia-induced metabolic dysfunction by using several approaches to delete hepatic AR via animal-, cell-, and clinical-based methodologies. We conditionally disrupted hepatocyte AR in female mice developmentally (LivARKO) or acutely by tail vein injection of an adeno-associated virus with a liver-specific promoter for Cre expression in ARfl/fl mice (adLivARKO). We observed normal metabolic function in littermate female Control (ARfl/fl ) and LivARKO (ARfl/fl ; Cre+/- ) mice. Following chronic DHT treatment, female Control mice treated with DHT (Con-DHT) developed impaired glucose tolerance, pyruvate tolerance, and insulin tolerance, not observed in LivARKO mice treated with DHT (LivARKO-DHT). Furthermore, during an euglycemic hyperinsulinemic clamp, the glucose infusion rate was improved in LivARKO-DHT mice compared to Con-DHT mice. Liver from LivARKO, and primary hepatocytes derived from LivARKO, and adLivARKO mice were protected from DHT-induced insulin resistance and increased gluconeogenesis. These data support a paradigm in which elevated androgens in females disrupt metabolic function via hepatic AR and insulin sensitivity was restored by deletion of hepatic AR.

DHT causes liver steatosis via transcriptional regulation of SCAP in normal weight female mice.

Hyperandrogenemia (HA) is a hallmark of polycystic ovary syndrome (PCOS) and is an integral element of non-alcoholic fatty liver disease (NALFD) in females. Administering low-dose dihydrotestosterone (DHT) induced a normal weight PCOS-like female mouse model displaying NAFLD. The molecular mechanism of HA-induced NAFLD has not been fully determined. We hypothesized that DHT would regulate hepatic lipid metabolism via increased SREBP1 expression leading to NAFLD. We extracted liver from control and low-dose DHT female mice; and performed histological and biochemical lipid profiles, Western blot, immunoprecipitation, chromatin immunoprecipitation, and real-time quantitative PCR analyses. DHT lowered the 65 kD form of cytosolic SREBP1 in the liver compared to controls. However, DHT did not alter the levels of SREBP2 in the liver. DHT mice displayed increased SCAP protein expression and SCAP-SREBP1 binding compared to controls. DHT mice exhibited increased AR binding to intron-8 of SCAP leading to increased SCAP mRNA compared to controls. FAS mRNA and protein expression was increased in the liver of DHT mice compared to controls. p-ACC levels were unaltered in the liver. Other lipid metabolism pathways were examined in the liver, but no changes were observed. Our findings support evidence that DHT increased de novo lipogenic proteins resulting in increased hepatic lipid content via regulation of SREBP1 in the liver. We show that in the presence of DHT, the SCAP-SREBP1 interaction was elevated leading to increased nuclear SREBP1 resulting in increased de novo lipogenesis. We propose that the mechanism of action may be increased AR binding to an ARE in SCAP intron-8.

Racial and Ethnic Differences in Metabolic Disease in Adolescents With Obesity and Polycystic Ovary Syndrome.

CONTEXT: Polycystic ovary syndrome (PCOS) is common and associated with metabolic syndrome. In the general population, metabolic disease varies by race and ethnicity. OBJECTIVE: This work aimed to examine in depth the interaction of race and ethnicity with PCOS-related metabolic disease in adolescent youth. METHODS: A secondary analysis was conducted of data from girls (age 12-21 years) with overweight or obesity (> 90 body mass index [BMI] percentile) and PCOS. Measurements included fasting hormone and metabolic measures, a 2-hour oral glucose tolerance test (OGTT), and magnetic resonance imaging for hepatic fat. Groups were categorized by race or ethnicity. RESULTS: Participants included 39 non-Hispanic White (NHW, age 15.7 ±â€…0.2 years; BMI 97.7 ±â€…0.2 percentile), 50 Hispanic (HW, 15.2 ±â€…0.3 years; 97.9 ±â€…0.3 percentile), and 12 non-Hispanic Black (NHB, 16.0 ±â€…0.6 years; 98.6 ±â€…0.4 percentile) adolescents. Hepatic markers of insulin resistance were worse in NHW, including lower sex hormone-binding globulin and higher triglycerides over high-density lipoprotein cholesterol (TGs/HDL-C) ratio (P = .002 overall, HW vs NHB [P = .009] vs NHW [P = 0.020]), although homeostasis model assessment of estimated insulin resistance was worst in NHB (P = .010 overall, NHW vs NHB P = .014). Fasting and 2-hour OGTT glucose were not different between groups, although glycated hemoglobin A1c (HbA1c) was lowest in NHW (overall P < .001, NHW 5.2 ±â€…0.3 vs HW 5.5 ±â€…0.3 P < .001 vs 5.7 ±â€…0.4%, P < .001). The frequency of hepatic steatosis (HW 62%, NHW 42%, NHB 25%, P = .032); low HDL-C < 40 mg/dL (HW 82%, NHW 61%, NHB 50%, P < .001) and prediabetes HbA1c 5.7% to 6.4% (NHB 50%, HW 36%, NHW 5%, P < .001) were different between the groups. CONCLUSION: Adolescents with PCOS appear to show similar racial and ethnic variation to the general population in terms of metabolic disease components.

Insulin signaling displayed a differential tissue-specific response to low-dose dihydrotestosterone in female mice.

Hyperandrogenemia and hyperinsulinemia are believed to play prominent roles in polycystic ovarian syndrome (PCOS). We explored the effects of low-dose dihydrotestosterone (DHT), a model of PCOS, on insulin signaling in metabolic and reproductive tissues in a female mouse model. Insulin resistance in the energy storage tissues is associated with type 2 diabetes. Insulin signaling in the ovaries and pituitary either directly or indirectly stimulates androgen production. Energy storage and reproductive tissues were isolated and molecular assays were performed. Livers and white adipose tissue (WAT) from DHT mice displayed lower mRNA and protein expression of insulin signaling intermediates. However, ovaries and pituitaries of DHT mice exhibited higher expression levels of insulin signaling genes/proteins. Insulin-stimulated p-AKT levels were blunted in the livers and WAT of the DHT mice but increased or remained the same in the ovaries and pituitaries compared with controls. Glucose uptake decreased in liver and WAT but was unchanged in pituitary and ovary of DHT mice. Plasma membrane GLUTs were decreased in liver and WAT but increased in ovary and pituitary of DHT mice. Skeletal muscle insulin-signaling genes were not lowered in DHT mice compared with control. DHT mice did not display skeletal muscle insulin resistance. Insulin-stimulated glucose transport increased in skeletal muscles of DHT mice compared with controls. DHT mice were hyperinsulinemic. However, the differential mRNA and protein expression pattern was independent of hyperinsulinemia in cultured hepatocytes and pituitary cells. These findings demonstrate a differential effect of DHT on the insulin-signaling pathway in energy storage vs. reproductive tissues independent of hyperinsulinemia.

A role for ataxia telangiectasia mutated in insulin-independent stimulation of glucose transport.

Literature reports suggest that ataxia telangiectasia mutated (ATM) can activate the AMP-activated protein kinase (AMPK), a protein that can stimulate glucose transport in skeletal muscle. We hypothesized that 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR), an AMPK activator, would increase glucose transport in mouse extensor digitorum longus (EDL) muscles in an ATM-dependent manner. AICAR-stimulated glucose transport was prevented by the ATM inhibitor KU-55933 despite normal stimulation of AMPK phosphorylation. Consistent with this, AICAR caused AMPK phosphorylation but not an increase of glucose transport in ATM-deficient (ATM-/-) muscles. S231 of TBC1D1 matches the sequence motif of ATM substrates, and phosphorylation of this site is known to inhibit TBC1D1 and lead to increased glucose transport. Accordingly, we assessed TBC1D1 phosphorylation and found that AICAR-stimulated phosphorylation of TBC1D1 at S231 did not occur in ATM-/- muscles. However, activation of ATM without activation of AMPK was insufficient to increase TBC1D1 phosphorylation. The data suggest that ATM plays a role in AICAR-stimulated glucose transport downstream of AMPK.

Androgen Receptor in the Ovary Theca Cells Plays a Critical Role in Androgen-Induced Reproductive Dysfunction.

Androgen and its receptor (AR) play a critical role in reproductive function under both physiological and pathophysiological conditions. Female AR global knockout mice are subfertile due to both neuroendocrine and ovarian defects. Female offspring from prenatally androgenized heterozygous AR pregnant mice showed rescued estrous cyclicity and fertility. Ar is expressed in granulosa cells, theca interstitial cells, and oocytes in the ovary. We created mice with theca-specific deletion of Ar (ThARKO) by crossing Cyp17-iCre mice that express Cre recombinase under cytochrome P450 17A1 (Cyp17) promoter with Arfl/fl mice. ThARKO mice exhibited no significant differences in pubertal onset or fertility compared with control littermates, and neither estrogen or testosterone levels were different between these groups. Therefore, Ar expression in theca cells likely does not influence fertility nor androgen levels in female mice. We then tested the role of AR in theca cells under hyperandrogenemic condition. After treatment with a pathophysiological level of dihydrotestosterone (DHT), control mice (control-DHT) showed acyclicity and infertility. However, estrous cycles and fertility were altered to a significantly less degree in ThARKO-DHT mice than in control-DHT mice. Messenger RNA (mRNA) levels of Lhcgr (luteinizing hormone receptor) and Timp1 (tissue inhibitor of metalloproteinase 1, and inhibitor of matrix metalloproteinase) were significantly lower in control-DHT ovary compared with control-no DHT ovaries, whereas mRNA levels of Fshr (follicle-stimulating hormone receptor) were significantly higher. Timp1 gene expression was comparable in the ThARKO-DHT and the control-no DHT ovary. We speculate that the preserved level of Timp1 in ThARKO-DHT mice contributes to retained reproductive function.

Low-Dose Dihydrotestosterone Drives Metabolic Dysfunction via Cytosolic and Nuclear Hepatic Androgen Receptor Mechanisms.

Androgen excess in women is associated with metabolic dysfunction (e.g., obesity, hyperinsulinemia, insulin resistance, and increased risk of type 2 diabetes) and reproductive dysfunction (e.g., polycystic ovaries, amenorrhea, dysregulated gonadotropin release, and infertility). We sought to identify the effects of androgen excess on glucose metabolic dysfunction and the specific mechanisms of action by which androgens are inducing pathology. We developed a mouse model that displayed pathophysiological serum androgen levels with normal body mass/composition to ensure that the phenotypes were directly from androgens and not an indirect consequence of obesity. We performed reproductive tests, metabolic tests, and hormonal assays. Livers were isolated and examined via molecular, biochemical, and histological analysis. Additionally, a low-dose dihydrotestosterone (DHT) cell model using H2.35 mouse hepatocytes was developed to study androgen effects on hepatic insulin signaling. DHT mice demonstrated impaired estrous cyclicity; few corpora lutea in the ovaries; glucose, insulin, and pyruvate intolerance; and lowered hepatic insulin action. Mechanistically, DHT increased hepatic androgen-receptor binding to phosphoinositide-3-kinase (PI3K)-p85, resulting in dissociation of PI3K-p85 from PI3K-p110, leading to reduced PI3K activity and decreased p-AKT and, thus, lowered insulin action. DHT increased gluconeogenesis via direct transcriptional regulation of gluconeogenic enzymes and coactivators. The hepatocyte model recapitulated the in vivo findings. The DHT-induced hepatocyte insulin resistance was reversed by the androgen-receptor antagonist, flutamide. These findings present a phenotype (i.e., impaired glucose tolerance and disrupted glucose metabolism) in a lean hyperandrogenemia model (low-dose DHT) and data to support 2 molecular mechanisms that help drive androgen-induced impaired glucose metabolism.

Role of GLUT1 in regulation of reactive oxygen species.

In skeletal muscle cells, GLUT1 is responsible for a large portion of basal uptake of glucose and dehydroascorbic acid, both of which play roles in antioxidant defense. We hypothesized that conditions that would decrease GLUT1-mediated transport would cause increased reactive oxygen species (ROS) levels in L6 myoblasts, while conditions that would increase GLUT1-mediated transport would result in decreased ROS levels. We found that the GLUT1 inhibitors fasentin and phloretin increased the ROS levels induced by antimycin A and the superoxide generator pyrogallol. However, indinavir, which inhibits GLUT4 but not GLUT1, had no effect on ROS levels. Ataxia telangiectasia mutated (ATM) inhibitors and activators, previously shown to inhibit and augment GLUT1-mediated transport, increased and decreased ROS levels, respectively. Mutation of an ATM target site on GLUT1 (GLUT1-S490A) increased ROS levels and prevented the ROS-lowering effect of the ATM activator doxorubicin. In contrast, expression of GLUT1-S490D lowered ROS levels during challenge with pyrogallol, prevented an increase in ROS when ATM was inhibited, and prevented the pyrogallol-induced decrease in insulin signaling and insulin-stimulated glucose transport. Taken together, the data suggest that GLUT1 plays a role in regulation of ROS and could contribute to maintenance of insulin action in the presence of ROS.

Impaired insulin-stimulated glucose transport in ATM-deficient mouse skeletal muscle.

There are reports that ataxia telangiectasia mutated (ATM) plays a role in insulin-stimulated Akt phosphorylation, although this is not the case in some cell types. Because Akt plays a key role in insulin signaling, which leads to glucose transport in skeletal muscle, the predominant tissue in insulin-stimulated glucose disposal, we examined whether insulin-stimulated Akt phosphorylation and (or) glucose transport would be decreased in skeletal muscle of mice lacking functional ATM, compared with muscle from wild-type mice. We found that in vitro insulin-stimulated Akt phosphorylation was normal in soleus muscle from mice with 1 nonfunctional allele of ATM (ATM+/-) and from mice with 2 nonfunctional alleles (ATM-/-). However, insulin did not stimulate glucose transport or the phosphorylation of AS160 in ATM-/- soleus. ATM protein level was markedly higher in wild-type extensor digitorum longus (EDL) than in wild-type soleus. In EDL from ATM-/- mice, insulin did not stimulate glucose transport. However, in contrast to findings for soleus, insulin-stimulated Akt phosphorylation was blunted in ATM-/- EDL, concomitant with a tendency for insulin-stimulated phosphatidylinositol 3-kinase activity to be decreased. Together, the findings suggest that ATM plays a role in insulin-stimulated glucose transport at the level of AS160 in muscle comprised of slow and fast oxidative-glycolytic fibers (soleus) and at the level of Akt in muscle containing fast glycolytic fibers (EDL).

ATM and GLUT1-S490 phosphorylation regulate GLUT1 mediated transport in skeletal muscle.

OBJECTIVE: The glucose and dehydroascorbic acid (DHA) transporter GLUT1 contains a phosphorylation site, S490, for ataxia telangiectasia mutated (ATM). The objective of this study was to determine whether ATM and GLUT1-S490 regulate GLUT1. RESEARCH DESIGN AND METHODS: L6 myoblasts and mouse skeletal muscles were used to study the effects of ATM inhibition, ATM activation, and S490 mutation on GLUT1 localization, trafficking, and transport activity. RESULTS: In myoblasts, inhibition of ATM significantly diminished cell surface GLUT1, glucose and DHA transport, GLUT1 externalization, and association of GLUT1 with Gα-interacting protein-interacting protein, C-terminus (GIPC1), which has been implicated in recycling of endosomal proteins. In contrast, ATM activation by doxorubicin (DXR) increased DHA transport, cell surface GLUT1, and the GLUT1/GIPC1 association. S490A mutation decreased glucose and DHA transport, cell surface GLUT1, and interaction of GLUT1 with GIPC1, while S490D mutation increased transport, cell surface GLUT1, and the GLUT1/GIPC1 interaction. ATM dysfunction or ATM inhibition reduced DHA transport in extensor digitorum longus (EDL) muscles and decreased glucose transport in EDL and soleus. In contrast, DXR increased DHA transport in EDL. CONCLUSIONS: These results provide evidence that ATM and GLUT1-S490 promote cell surface GLUT1 and GLUT1-mediated transport in skeletal muscle associated with upregulation of the GLUT1/GIPC1 interaction.