OBJECTIVE:Both obesity and adipose tissue fibrosis are associated with insulin resistance, which can improve with weight loss. We previously found increased adipocyte-specific secretion of the novel adipokine CRISPLD2 during weight loss. In this study, we further explore the function of adipose CRISPLD2, which others suggest may regulate inflammation and fibrosis in a variety of tissues. METHODS:We designed mice with adipose-specific doxycycline-inducible overexpression of CRISPLD2 (CLD2AD) to assess adipose-specific effects on tissue structure and function on chow or high-fat diets. The effects of prolonged excess CRISPLD2 were determined after 7 months, including stromal vascular fraction analysis by single-cell RNA-seq. CRISPLD2 cell surface signaling was explored in 3T3-L1 adipocytes via transwell assays, and adipocyte binding partners were determined in unbiased binding screening by mass spectrometry. RESULTS:CLD2AD mice had decreased adipocyte size but unchanged fat mass. Long-term CRISPLD2 overexpression led to downregulation of collagen transcription and decreased fibrosis. CRISPLD2 induced Ifng transcription in adipocytes in vitro and bound multiple adipocyte cell surface proteins, including nucleolin. Finally, obese CLD2AD mice had decreased adipocyte size and improved glucose tolerance, with no change in fat mass. CONCLUSIONS:These data suggest a model wherein CRISPLD2 can both regulate adipose tissue fibrosis and improve insulin sensitivity.

Obesity is a primary risk factor for type 2 diabetes, with excess adiposity leading to worsening insulin resistance and an increase in adipose tissue inflammation. Conversely, during weight loss there is improved insulin sensitivity with decreased adiposity, including a decrease in adipocyte size, clearance of lipid, and changes to the inflammatory signaling milieu. Adipocyte-secreted factors during weight loss could be a novel target to aid in improved outcomes in diabetes and obesity. We previously identified a novel adipocyte-secreted protein, CRISPLD2, that is uniquely up-regulated in expression and secretion during weight loss. CRISPLD2 secretion is up-regulated by lipolytic signals, down-regulated by insulin, and correlates strongly with insulin sensitivity in humans. We have now found that secreted CRISPLD2 is able to specifically alter gene expression, including an increase ccl2 transcription in 3T3-L1 adipocytes by almost 2-fold (p<0.005). However, the signaling pathways, receptor, and function of CRISPLD2 within adipocytes and adipose tissue have yet to be determined. To determine if excess exogenous CRISPLD2 can alter adipose function, we developed a transgenic mouse with doxycycline-inducible adipose-specific overexpression of CRISPLD2. Induced CRISPLD2 overexpression over 4 weeks leads to a significant decrease in adipocyte size in visceral adipose tissue in lean animals, despite no change in overall adipose depot size. Finally, utilizing IP-MS, we found that CRISPLD2 binds several adipocyte cell surface proteins, intriguingly including nucleolin, which has been previously shown to function as a receptor in inflammatory pathways. Taken together, these data suggest that CRISPLD2 may function as a novel adipokine, playing a role in lipid turnover and adipocyte size in weight loss. B.A. Griesel: Stock/Shareholder; Pfizer Inc., Moderna, Inc., Weight Watchers International. Other Relationship; Weight Watchers International. A.L. Olson: None. D. Sparling: None. Oklahoma Center for the Advancement of Science and Technology (PR-HR21-005)

Age-dependent changes in adipose tissue are thought to play a role in development of insulin resistance. A major age-dependent change in adipose tissue is the downregulation of key proteins involved in carbohydrate metabolism. In the current study, we investigate the role of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 (PFKFB3) a key governor of the rate of glycolysis in adipocytes via the synthesis of fructose-2,6-bisphosphate that was significantly downregulated in aged mice. We employed an adipocyte-specific PFKFB3 mouse line to investigate the role of PFKFB3 on adipocyte function. In both aged mice and PFKFB3-knockout mice, we observed an increase in O-glcNAcylated proteins consistent with a shift in glucose metabolism toward the hexosamine biosynthetic pathway. Under chow-fed conditions, PFKFB3 knockout resulted in significantly smaller adipocyte area, but no difference in total fat mass. While glucose tolerance was unchanged under chow conditions, when mice were challenged with a 4 weeks high-fat feeding, PFKFB3 deletion led to a greater decrease in glucose tolerance as well as a significant increase in macrophage infiltration. These results indicate that perturbation of the glycolytic pathway in adipose tissue has multiple effects of adipocyte biology and may play a significant role in metabolic changes associated with aging. Results of this student support the notion that changes in glucose metabolism in adipose tissue impact whole-body metabolism.

Apelin in promoting metastatic phenotypes

IntroductionMild cognitive impairment (MCI) is a prodromal stage to dementia, affecting up to 20% of the aging population worldwide. Patients with MCI have an annual conversion rate to dementia of 15–20%. Thus, conditions that increase the conversion from MCI to dementia are of the utmost public health concern. The COVID-19 pandemic poses a significant impact on our aging population with cognitive decline as one of the leading complications following recovery from acute infection. Recent findings suggest that COVID-19 increases the conversion rate from MCI to dementia in older adults. Hence, we aim to uncover a mechanism for COVID-19 induced cognitive impairment and progression to dementia to pave the way for future therapeutic targets that may mitigate COVID-19 induced cognitive decline.MethodologyA prospective longitudinal study is conducted at the University of Oklahoma Health Sciences Center. Patients are screened in the Department of Neurology and must have a formal diagnosis of MCI, and MRI imaging prior to study enrollment. Patients who meet the inclusion criteria are enrolled and followed-up at 18-months after their first visit. Visit one and 18-month follow-up will include an integrated and cohesive battery of vascular and cognitive measurements, including peripheral endothelial function (flow-mediated dilation, laser speckle contrast imaging), retinal and cerebrovascular hemodynamics (dynamic vessel retinal analysis, functional near-infrared spectroscopy), and fluid and crystalized intelligence (NIH-Toolbox,n-back). Multiple logistic regression will be used for primary longitudinal data analysis to determine whether COVID-19 related impairment in neurovascular coupling and increases in white matter hyperintensity burden contribute to progression to dementia.

Effect of etomoxir on OvCa cell migration

Antibody catalog numbers and dilutions used in western blots

TCGA data analysis for correlation between APJ and CD36, STAT3.

CD36 expression regulation in APJ cells

Lipid droplet accumulation in APJ knockdown cells

CPT1a and AMPK activation downstream of APJ

SSO inhibits lipid droplet accumulation

Fatty acid oxidation in APJ knockdown cells

Deficient glucose transport and glucose disposal are key pathologies leading to impaired glucose tolerance and risk of type 2 diabetes. The cloning and identification of the family of facilitative glucose transporters have helped to identify that underlying mechanisms behind impaired glucose disposal, particularly in muscle and adipose tissue. There is much more than just transporter protein concentration that is needed to regulate whole body glucose uptake and disposal. The purpose of this review is to discuss recent findings in whole body glucose disposal. We hypothesize that impaired glucose uptake and disposal is a consequence of mismatched energy input and energy output. Decreasing the former while increasing the latter is key to normalizing glucose homeostasis

Abstract Adipose tissue, which can provide adipokines and nutrients to tumors, plays a key role in promoting ovarian cancer metastatic lesions in peritoneal cavity. The adipokine apelin promotes ovarian cancer metastasis and progression through its receptor APJ, which regulates cell proliferation, energy metabolism, and angiogenesis. The objective of this study was to investigate the functional role and mechanisms of the apelin-APJ pathway in ovarian cancer metastasis, especially in context of tumor cell–adipocyte interactions. When co-cultured in the conditioned media (AdipoCM) derived from 3T3-L1 adipocytes, which express and secrete high apelin, human ovarian cancer cells with high APJ expression showed significant increases in migration and invasion in vitro. We also found that cells expressing high levels of APJ had increased cell adhesion to omentum ex vivo, and preferentially “home-in” on the omentum in vivo. These apelin-induced pro-metastatic effects were reversed by APJ antagonist F13A in a dose-dependent manner. Apelin-APJ activation increased lipid droplet accumulation in ovarian cancer cells, which was further intensified in the presence of AdipoCM and reversed by F13A or APJ knockdown. Mechanistically, this increased lipid uptake was mediated by CD36 upregulation via APJ-STAT3 activation, and the lipids were utilized in promoting fatty acid oxidation via activation of AMPK-CPT1a axis. Together, our studies demonstrate that adipocyte-derived apelin activates APJ-expressing tumor cells in a paracrine manner, promoting lipid uptake and utilization and providing energy for ovarian cancer cell survival at the metastatic sites. Hence, the apelin-APJ pathway presents a novel therapeutic target to curb ovarian cancer metastasis. Implications: Targeting the APJ pathway in high-grade serous ovarian carcinoma is a novel strategy to inhibit peritoneal metastasis.