Modeling human heterogeneity of obesity with diversity outbred mice reveals a fat mass-dependent therapeutic window for resolvin E1.

Resolvin E1 (RvE1), a specialized pro-resolving mediator (SPM), improves glucose homeostasis in inbred mouse models of obesity. However, an impediment toward translation is that obesity is a highly heterogenous disease in which individuals will respond very differently to interventions such as RvE1. Thus, there is a need to study SPMs in the context of modeling the heterogeneity of obesity that is observed in humans. We investigated how RvE1 controls the concentration of key circulating metabolic biomarkers using diversity outbred (DO) mice, which mimic human heterogeneity. We first demonstrate that weights of DO mice can be classified into distinct distributions of fat mass (i.e., modeling differing classes of obesity) in response to a high-fat diet and in the human population when examining body composition. Next, we show RvE1 administration based on body weight for four consecutive days after giving mice a high-fat diet led to approximately half of the mice responding positively for serum total gastric inhibitory polypeptide (GIP), glucagon, insulin, glucose, leptin, and resistin. Interestingly, RvE1 improved hyperleptinemia most effectively in the lowest class of fat mass despite adjusting the dose of RvE1 with increasing adiposity. Furthermore, leptin levels after RvE1 treatment were the lowest in those mice that were also RvE1 positive responders for insulin and resistin. Collectively, these results suggest a therapeutic fat mass-dependent window for RvE1, which should be considered in future clinical trials. Moreover, the data underscore the importance of studying SPMs with heterogenous mice as a step toward precision SPM administration in humans.

Resolvin E1 derived from eicosapentaenoic acid prevents hyperinsulinemia and hyperglycemia in a host genetic manner.

Eicosapentaenoic acid (EPA) has garnered attention after the success of the REDUCE-IT trial, which contradicted previous conclusions on EPA for cardiovascular disease risk. Here we first investigated EPA's preventative role on hyperglycemia and hyperinsulinemia. EPA ethyl esters prevented obesity-induced glucose intolerance, hyperinsulinemia, and hyperglycemia in C57BL/6J mice. Supporting NHANES analyses showed that fasting glucose levels of obese adults were inversely related to EPA intake. We next investigated how EPA improved murine hyperinsulinemia and hyperglycemia. EPA overturned the obesity-driven decrement in the concentration of 18-hydroxyeicosapentaenoic acid (18-HEPE) in white adipose tissue and liver. Treatment of obese inbred mice with RvE1, the downstream immunoresolvant metabolite of 18-HEPE, but not 18-HEPE itself, reversed hyperinsulinemia and hyperglycemia through the G-protein coupled receptor ERV1/ChemR23. To translate the findings, we determined if the effects of RvE1 were dependent on host genetics. RvE1's effects on hyperinsulinemia and hyperglycemia were divergent in diversity outbred mice that model human genetic variation. Secondary SNP analyses further confirmed extensive genetic variation in human RvE1/EPA-metabolizing genes. Collectively, the data suggest EPA prevents hyperinsulinemia and hyperglycemia, in part, through RvE1's activation of ERV1/ChemR23 in a host genetic manner. The studies underscore the need for personalized administration of RvE1 based on genetic/metabolic enzyme profiles.

Chemotherapy selection pressure alters sphingolipid composition and mitochondrial bioenergetics in resistant HL-60 cells.

The combination of daunorubicin (dnr) and cytarabine (Ara-C) is a cornerstone of treatment for acute myelogenous leukemia (AML); resistance to these drugs is a major cause of treatment failure. Ceramide, a sphingolipid (SL), plays a critical role in cancer cell apoptosis in response to chemotherapy. Here, we investigated the effects of chemotherapy selection pressure with Ara-C and dnr on SL composition and enzyme activity in the AML cell line HL-60. Resistant cells, those selected for growth in Ara-C- and dnr-containing medium (HL-60/Ara-C and HL-60/dnr, respectively), demonstrated upregulated expression and activity of glucosylceramide synthase, acid ceramidase (AC), and sphingosine kinase 1 (SPHK1); were more resistant to ceramide than parental cells; and displayed sensitivity to inhibitors of SL metabolism. Lipidomic analysis revealed a general ceramide deficit and a profound upswing in levels of sphingosine 1-phosphate (S1P) and ceramide 1-phosphate (C1P) in HL-60/dnr cells versus parental and HL-60/Ara-C cells. Both chemotherapy-selected cells also exhibited comprehensive upregulations in mitochondrial biogenesis consistent with heightened reliance on oxidative phosphorylation, a property that was partially reversed by exposure to AC and SPHK1 inhibitors and that supports a role for the phosphorylation system in resistance. In summary, dnr and Ara-C selection pressure induces acute reductions in ceramide levels and large increases in S1P and C1P, concomitant with cell resilience bolstered by enhanced mitochondrial remodeling. Thus, strategic control of ceramide metabolism and further research to define mitochondrial perturbations that accompany the drug-resistant phenotype offer new opportunities for developing therapies that regulate cancer growth.

Ceramide-tamoxifen regimen targets bioenergetic elements in acute myelogenous leukemia.

The objective of our study was to determine the mechanism of action of the short-chain ceramide analog, C6-ceramide, and the breast cancer drug, tamoxifen, which we show coactively depress viability and induce apoptosis in human acute myelogenous leukemia cells. Exposure to the C6-ceramide-tamoxifen combination elicited decreases in mitochondrial membrane potential and complex I respiration, increases in reactive oxygen species (ROS), and release of mitochondrial proapoptotic proteins. Decreases in ATP levels, reduced glycolytic capacity, and reduced expression of inhibitors of apoptosis proteins also resulted. Cytotoxicity of the drug combination was mitigated by exposure to antioxidant. Cells metabolized C6-ceramide by glycosylation and hydrolysis, the latter leading to increases in long-chain ceramides. Tamoxifen potently blocked glycosylation of C6-ceramide and long-chain ceramides. N-desmethyltamoxifen, a poor antiestrogen and the major tamoxifen metabolite in humans, was also effective with C6-ceramide, indicating that traditional antiestrogen pathways are not involved in cellular responses. We conclude that cell death is driven by mitochondrial targeting and ROS generation and that tamoxifen enhances the ceramide effect by blocking its metabolism. As depletion of ATP and targeting the "Warburg effect" represent dynamic metabolic insult, this ceramide-containing combination may be of utility in the treatment of leukemia and other cancers.

Reducing Human Immunodeficiency Virus and Sexually Transmitted Infections Risk in African American Women with At-Risk Male Partners: A Randomized Trial.

Background: We examined the efficacy of the Females of African American Legacy Empowering Self (FemAALES) intervention in a cohort of 203 publicly insured Black women in Los Angeles. Materials and Methods: Women who reported recent sex with a male partner who was at increased risk for infection by human immunodeficiency virus (HIV) and sexually transmitted infections (STI) were randomized to the six-session FemAALES intervention or to a single client-centered family planning and STI/HIV counseling session. Participants were followed at 3 and 9 months post-intervention. To investigate between-group behavioral changes in condomless sex in the prior 90 days and other HIV/STI risks, we used generalized estimating equations that accounted for repeated observations in individuals. Results: Most participants (mean age 34 ± 11 standard deviation) were low-income and unemployed, despite three-quarters having completed high school or the equivalent. The most common HIV/STI risk factors among recent male partners were incarceration (58.8%) and concurrent sex with other women (72.2%). At 3 months, the FemAALEs group showed a larger increase in the odds of asking their partner to test (adjusted odds ratio = 2.14; 95% confidence interval [CI], 1.02-4.47; p = 0.0431) and in sexual health self-efficacy scores (adjß = 1.82; 95% CI, 0.02-3.62; p = 0.0471) compared to the control group, although these changes did not hold at 9 months. Both groups showed statistically significant declines in the frequency of several sexual risk factors between baseline and 9 months. Conclusion: Although we did not find evidence that the FemAALES intervention was more efficacious than the less-intensive control condition in reducing sexual risk behaviors, the overall declines in risk behaviors we observed warrant further research. ClinicalTrials.gov (Identifier: NCT02189876).

Sexual Health Behavior and Mental Health Among Older African American Women: The Sistahs, Sexuality, and Mental Health Well-Being Project.

BACKGROUND: In Los Angeles County, the rates of sexually transmitted infections and diseases among African Americans represent a significant public health disparity. Older African American women are at particular risk as they are more likely to engage in high-risk sexual behaviors and report social isolation and loneliness than their younger counterparts. However, the literature on the relationship between sexual health and mental health in this group is limited. The purpose of this study was to use a community-based participatory research (CBPR) approach to better understand sexual health behaviors and mental health among African American women over 50 years of age who reside in South Los Angeles. MATERIALS AND METHODS: This project was divided into two phases. Phase I (January-March 2017) of the project consisted of four dialog/focus groups (N = 45) (ages: 50-80; Mage = 67). The purpose of Phase II (April 2017) was to present study results from Phase I to the community via a community-based conference, as well as gather feedback and generate discussion about the next steps for community prevention/intervention. RESULTS: Women reported that they did not feel comfortable discussing sexual practices with their physician, partners, and friends. Most women identified depression, loneliness, and self-esteem issues as reasons for engaging in high-risk sexual behaviors. During Phase II, potential intervention avenues emerged to address issues such as lack of physician-patient communication, lack of community support, and dialogs about sex. CONCLUSIONS: The use of CBPR greatly enhanced our knowledge of the core issues surrounding sexual health and mental health among older African American women.

Role of P-glycoprotein inhibitors in ceramide-based therapeutics for treatment of cancer.

The anticancer properties of ceramide, a sphingolipid with potent tumor-suppressor properties, can be dampened via glycosylation, notably in multidrug resistance wherein ceramide glycosylation is characteristically elevated. Earlier works using the ceramide analog, C6-ceramide, demonstrated that the antiestrogen tamoxifen, a first generation P-glycoprotein (P-gp) inhibitor, blocked C6-ceramide glycosylation and magnified apoptotic responses. The present investigation was undertaken with the goal of discovering non-anti-estrogenic alternatives to tamoxifen that could be employed as adjuvants for improving the efficacy of ceramide-centric therapeutics in treatment of cancer. Herein we demonstrate that the tamoxifen metabolites, desmethyltamoxifen and didesmethyltamoxifen, and specific, high-affinity P-gp inhibitors, tariquidar and zosuquidar, synergistically enhanced C6-ceramide cytotoxicity in multidrug resistant HL-60/VCR acute myelogenous leukemia (AML) cells, whereas the selective estrogen receptor antagonist, fulvestrant, was ineffective. Active C6-ceramide-adjuvant combinations elicited mitochondrial ROS production and cytochrome c release, and induced apoptosis. Cytotoxicity was mitigated by introduction of antioxidant. Effective adjuvants markedly inhibited C6-ceramide glycosylation as well as conversion to sphingomyelin. Active regimens were also effective in KG-1a cells, a leukemia stem cell-like line, and in LoVo human colorectal cancer cells, a solid tumor model. In summary, our work details discovery of the link between P-gp inhibitors and the regulation and potentiation of ceramide metabolism in a pro-apoptotic direction in cancer cells. Given the active properties of these adjuvants in synergizing with C6-ceramide, independent of drug resistance status, stemness, or cancer type, our results suggest that the C6-ceramide-containing regimens could provide alternative, promising therapeutic direction, in addition to finding novel, off-label applications for P-gp inhibitors.

Short-chain ceramides depress integrin cell surface expression and function in colorectal cancer cells.

Colorectal cancer (CRC) is highly metastatic, significantly so to liver, a characteristic that embodies one of the most challenging aspects of treatment. The integrin family of cell-cell and cell-matrix adhesion receptors plays a central role in migration and invasion, functions that underlie metastatic potential. In the present work we sought to determine the impact of ceramide, which plays a key modulatory role in cancer suppression, on integrin cell surface expression and function in CRC cells in order to reveal possible ceramide-centric effects on tumor cell motility. Human CRC cells LoVo, HT-29, and HCT-116 were employed, which represent lines established from primary and metastatic sites. A cell-permeable, short-chain analog, C6-ceramide, was used as ceramide mimic. Exposure of cells to C6-ceramide (24 h) promoted a dose-dependent (2.5-10 µM) decrease in the expression of cell surface ß1 and ß4 integrin subunits in all cell lines; at 10 µM C6-ceramide, the decreases ranged from 30 to 50% of the control. Expression of cell surface αVß6 integrin, which is associated with advanced invasion in CRC, was also suppressed by C6-ceramide. Decreases in integrin expression translated to diminished cellular adhesion, 50% of the control at 5 µM C6-ceramide, and markedly reduced cellular migration, approximately 30-40% of the control in all cell lines. Physicochemical examination revealed potent efficacy of nano-formulated C6-ceramide, but inferior activity of dihydro-C6-ceramide and L-C6-ceramide, compared to the unsaturated counterpart and the natural d-enantiomer, respectively. These studies demonstrate novel actions of ceramides that may have application in suppression of tumor metastasis, in addition to their known tumor suppressor effects.

Dynamics of ceramide generation and metabolism in response to fenretinide--Diversity within and among leukemia.

Fenretinide, N-(4-hydroxyphenyl)retinamide, (4-HPR), a synthetic retinoid, owes its cancer-toxic effects in part to the generation of ceramide, a potent tumor-suppressing sphingolipid. As such, 4-HPR has garnered considerable interest as a chemotherapeutic. Cancer cells, however, via various metabolic routes, inactivate ceramide, and this can limit 4-HPR efficacy. As relatively little is known regarding 4-HPR-induced ceramide management in acute myelogeneous leukemia (AML), we undertook the present study to evaluate the impact of 4-HPR on ceramide production, metabolism, and cytotoxicity. In KG-1, HL-60, and HL-60/VCR (multidrug resistant) human leukemia cells, 4-HPR induced 15-, 2-, and 20-fold increases in ceramide (measured using [3H]palmitic acid), respectively. By use of specific inhibitors we show that ceramide was produced by sphingomyelinase and de novo pathways in response to 4-HPR exposure. HL-60/VCR cells metabolized ceramide to glucosylceramide (GC). 4-HPR exposure (1.25-10 µM) reduced viability in all cell lines, with approximate IC50's ranging from 1 to 8.0 µM. Reactive oxygen species (ROS) were generated in response to 4-HPR treatment, and the concomitant cytotoxicity was reversed by addition of vitamin E. 4-HPR was not cytotoxic nor did it elicit ceramide formation in K562, a chronic myeloid leukemia cell line; however, K562 cells were sensitive to a cell-deliverable form of ceramide, C6-ceramide. Treatment of Molt-3, an acute lymphoblastic leukemia cell line, with 4-HPR revealed moderate ceramide production (5-fold over control), robust conversion of ceramide to GC and sphingomyelin, and resistance to 4-HPR and C6-ceramide. In conclusion, this work demonstrates diversity within and among leukemia in 4-HPR sensitivity and ceramide generation and subsequent metabolism. As such, knowledge of these metabolic pathways can provide guidance for enhancing ceramide-driven effects of 4-HPR in treatment of leukemia.

Assessment of eating disorders: comparison of interview and questionnaire data from a long-term follow-up study of bulimia nervosa.

OBJECTIVE: This paper examines diagnostic agreement between interview and questionnaire assessments of women participating in a long-term follow-up study of bulimia nervosa. METHODS: Women (N = 162) completed follow-up evaluations comprising questionnaires and either face-to-face or telephone interviews. RESULTS: Consistent with previous research, rates of eating disorders were higher when assessed by questionnaire than when assessed by interview; however, rates of full bulimia nervosa were similar. Overall diagnostic agreement was adequate for eating disorders (kappa=.64) but poor for bulimia nervosa (kappa=.49), with greater agreement between questionnaires and telephone interviews (kappa's range: .67-.71) than between questionnaires and face-to-face interviews (kappa's range: .35-.58). CONCLUSION: Findings support the possibility that increased rates of eating pathology on questionnaire assessments may be due, in part, to increased candor when participants feel more anonymous. Questionnaire assessments may not be inferior to interview assessments; they may reveal different aspects of disordered eating.

Long-term impact of treatment in women diagnosed with bulimia nervosa.

OBJECTIVE: Both cognitive-behavioral therapy (CBT) and antidepressant medication have demonstrated efficacy in the treatment of bulimia nervosa. However, data concerning the long-term impact of such treatments have been limited. This study sought to determine if treatment with CBT and antidepressant medication was associated with better long-term outcome among women diagnosed with bulimia nervosa. METHOD: Women (N = 101) who completed a controlled treatment study of bulimia nervosa participated in follow-up assessments approximately 10 years later. RESULTS: Women who received treatment with CBT or antidepressant medication or both reported improved social adjustment at long-term follow-up compared with women randomized to the placebo condition. DISCUSSION: Treatments with demonstrated efficacy for short-term outcome appear to improve psychosocial function at long-term follow-up among women initially diagnosed with bulimia nervosa.