Genetic variant rs1205 is associated with COVID-19 outcomes: The Strong Heart Study and Strong Heart Family Study.

BACKGROUND: Although COVID-19 infection has been associated with a number of clinical and environmental risk factors, host genetic variation has also been associated with the incidence and morbidity of infection. The CRP gene codes for a critical component of the innate immune system and CRP variants have been reported associated with infectious disease and vaccination outcomes. We investigated possible associations between COVID-19 outcome and a limited number of candidate gene variants including rs1205. METHODOLOGY/PRINCIPAL FINDINGS: The Strong Heart and Strong Heart Family studies have accumulated detailed genetic, cardiovascular risk and event data in geographically dispersed American Indian communities since 1988. Genotypic data and 91 COVID-19 adjudicated deaths or hospitalizations from 2/1/20 through 3/1/23 were identified among 3,780 participants in two subsets. Among 21 candidate variants including genes in the interferon response pathway, APOE, TMPRSS2, TLR3, the HLA complex and the ABO blood group, only rs1205, a 3' untranslated region variant in the CRP gene, showed nominally significant association in T-dominant model analyses (odds ratio 1.859, 95%CI 1.001-3.453, p = 0.049) after adjustment for age, sex, center, body mass index, and a history of cardiovascular disease. Within the younger subset, association with the rs1205 T-Dom genotype was stronger, both in the same adjusted logistic model and in the SOLAR analysis also adjusting for other genetic relatedness. CONCLUSION: A T-dominant genotype of rs1205 in the CRP gene is associated with COVID-19 death or hospitalization, even after adjustment for relevant clinical factors and potential participant relatedness. Additional study of other populations and genetic variants of this gene are warranted.

Longitudinal Lipidomic Signature of Coronary Heart Disease in American Indian People.

BACKGROUND: Dyslipidemia is an independent risk factor for coronary heart disease (CHD). Standard lipid panel cannot capture the complexity of the blood lipidome (ie, all molecular lipids in the blood). To date, very few large-scale epidemiological studies have assessed the full spectrum of the blood lipidome on risk of CHD, especially in a longitudinal setting. METHODS AND RESULTS: Using an untargeted liquid chromatography-mass spectrometry, we repeatedly measured 1542 lipid species from 1835 unique American Indian participants who attended 2 clinical visits (≈5.5 years apart) and followed up to 17.8 years in the Strong Heart Family Study (SHFS). We first identified baseline lipid species associated with risk of CHD, followed by replication in a European population. The model adjusted for age, sex, body mass index, smoking, hypertension, diabetes, low-density lipoprotein cholesterol, estimated glomerular filtration rate, education, and physical activity at baseline. We then examined the longitudinal association between changes in lipid species and changes in cardiovascular risk factors during follow-up. Multiple testing was controlled by the false discovery rate. We found that baseline levels of multiple lipid species (eg, phosphatidylcholines, phosphatidylethanolamines, and ceramides) were associated with the risk of CHD and improved the prediction accuracy over conventional risk factors in American Indian people. Some identified lipids in American Indian people were replicated in European people. Longitudinal changes in multiple lipid species (eg, acylcarnitines, phosphatidylcholines, and triacylglycerols) were associated with changes in cardiovascular risk factors. CONCLUSIONS: Baseline plasma lipids and their longitudinal changes over time are associated with risk of CHD. These findings provide novel insights into the role of dyslipidemia in CHD.

Plasma lipidomic markers of diet quality are associated with incident coronary heart disease in American Indian adults: the Strong Heart Family Study.

BACKGROUND: Identifying lipidomic markers of diet quality is needed to inform the development of biomarkers of diet, and to understand the mechanisms driving the diet- coronary heart disease (CHD) association. OBJECTIVES: This study aimed to identify lipidomic markers of diet quality and examine whether these lipids are associated with incident CHD. METHODS: Using liquid chromatography-mass spectrometry, we measured 1542 lipid species from 1694 American Indian adults (aged 18-75 years, 62% female) in the Strong Heart Family Study. Participants were followed up for development of CHD through 2020. Information on the past year diet was collected using the Block Food Frequency Questionnaire, and diet quality was assessed using the Alternative Healthy Eating Index-2010 (AHEI). Mixed-effects linear regression was used to identify individual lipids cross-sectionally associated with AHEI. In prospective analysis, Cox frailty model was used to estimate the hazard ratio (HR) of each AHEI-related lipid for incident CHD. All models were adjusted for age, sex, center, education, body mass index, smoking, alcohol drinking, level of physical activity, energy intake, diabetes, hypertension, and use of lipid-lowering drugs. Multiple testing was controlled at a false discovery rate of <0.05. RESULTS: Among 1542 lipid species measured, 71 lipid species (23 known), including acylcarnitine, cholesterol esters, glycerophospholipids, sphingomyelins and triacylglycerols, were associated with AHEI. Most of the identified lipids were associated with consumption of ω-3 (n-3) fatty acids. In total, 147 participants developed CHD during a mean follow-up of 17.8 years. Among the diet-related lipids, 10 lipids [5 known: cholesterol ester (CE)(22:5)B, phosphatidylcholine (PC)(p-14:0/22:1)/PC(o-14:0/22:1), PC(p-38:3)/PC(o-38:4)B, phosphatidylethanolamine (PE)(p-18:0/20:4)/PE(o-18:0/20:4), and sphingomyelin (d36:2)A] were associated with incident CHD. On average, each standard deviation increase in the baseline level of these 5 lipids was associated with 17%-23% increased risk of CHD (from HR: 1.17; 95% CI: 1, 1.36; to HR: 1.23; 95% CI: 1.05, 1.43). CONCLUSIONS: In this study, lipidomic markers of diet quality in American Indian adults are found. Some diet-related lipids are associated with risk of CHD beyond established risk factors.

Longitudinal lipidomic signatures of all-cause and CVD mortality in American Indians: findings from the Strong Heart Study.

Dyslipidemia is an independent and modifiable risk factor for aging and age-related disorders. Routine lipid panel cannot capture all individual lipid species in blood (i.e., blood lipidome). To date, a comprehensive assessment of the blood lipidome associated with mortality is lacking in large-scale community-dwelling individuals, especially in a longitudinal setting. Using liquid chromatograph-mass spectrometry, we repeatedly measured individual lipid species in 3,821 plasma samples collected at two visits (~ 5.5 years apart) from 1,930 unique American Indians in the Strong Heart Family Study. We first identified baseline lipids associated with risks for all-cause mortality and CVD mortality (mean follow-up period: 17.8 years) in American Indians, followed by replication of top hits in European Caucasians in the Malmö Diet and Cancer-Cardiovascular Cohort (n = 3,943, mean follow-up period: 23.7 years). The model adjusted age, sex, BMI, smoking, hypertension, diabetes, and LDL-c at baseline. We then examined the associations between changes in lipid species and risk of mortality. Multiple testing was controlled by false discovery rate (FDR). We found that baseline levels and longitudinal changes of multiple lipid species, e.g., cholesterol esters, glycerophospholipids, sphingomyelins, and triacylglycerols, were significantly associated with risks of all-cause or CVD mortality. Many lipids identified in American Indians could be replicated in European Caucasians. Network analysis identified differential lipid networks associated with risk of mortality. Our findings provide novel insight into the role of dyslipidemia in disease mortality and offer potential biomarkers for early prediction and risk reduction in American Indians and other ethnic groups.

Evaluating situational judgment test use and diversity in admissions at a southern US medical school.

INTRODUCTION: Situational judgment tests have been adopted by medical schools to assess decision-making and ethical characteristics of applicants. These tests are hypothesized to positively affect diversity in admissions by serving as a noncognitive metric of evaluation. The purpose of this study was to evaluate the performance of the Computer-based Assessment for Sampling Personal Characteristics (CASPer) scores in relation to admissions interview evaluations. METHODS: This was a cohort study of applicants interviewing at a public school of medicine in the southeastern United States in 2018 and 2019. Applicants took the CASPer test prior to their interview day. In-person interviews consisted of a traditional interview and multiple-mini-interview (MMI) stations. Between subjects, analyses were used to compare scores from traditional interviews, MMIs, and CASPer across race, ethnicity, and gender. RESULTS: 1,237 applicants were interviewed (2018: n = 608; 2019: n = 629). Fifty-seven percent identified as female. Self-identified race/ethnicity included 758 White, 118 Black or African-American, 296 Asian, 20 Native American or Alaskan Native, 1 Native Hawaiian or Other Pacific Islander, and 44 No response; 87 applicants identified as Hispanic. Black or African-American, Native American or Alaskan Native, and Hispanic applicants had significantly lower CASPer scores than other applicants. Statistically significant differences in CASPer percentiles were identified for gender and race; however, between subjects, comparisons were not significant. CONCLUSIONS: The CASPer test showed disparate scores across racial and ethnic groups in this cohort study and may not contribute to minimizing bias in medical school admissions.

Cancer mortality in a population-based cohort of American Indians - The strong heart study.

BACKGROUND: Cancer mortality among American Indian (AI) people varies widely, but factors associated with cancer mortality are infrequently assessed. METHODS: Cancer deaths were identified from death certificate data for 3516 participants of the Strong Heart Study, a population-based cohort study of AI adults ages 45-74 years in Arizona, Oklahoma, and North and South Dakota. Cancer mortality was calculated by age, sex and region. Cox proportional hazards model was used to assess independent associations between baseline factors in 1989 and cancer death by 2010. RESULTS: After a median follow-up of 15.3 years, the cancer death rate per 1000 person-years was 6.33 (95 % CI 5.67-7.04). Cancer mortality was highest among men in North/South Dakota (8.18; 95 % CI 6.46-10.23) and lowest among women in Arizona (4.57; 95 % CI 2.87-6.92). Factors independently associated with increased cancer mortality included age, current or former smoking, waist circumference, albuminuria, urinary cadmium, and prior cancer history. Factors associated with decreased cancer mortality included Oklahoma compared to Dakota residence, higher body mass index and total cholesterol. Sex was not associated with cancer mortality. Lung cancer was the leading cause of cancer mortality overall (1.56/1000 person-years), but no lung cancer deaths occurred among Arizona participants. Mortality from unspecified cancer was relatively high (0.48/100 person-years; 95 % CI 0.32-0.71). CONCLUSIONS: Regional variation in AI cancer mortality persisted despite adjustment for individual risk factors. Mortality from unspecified cancer was high. Better understanding of regional differences in cancer mortality, and better classification of cancer deaths, will help healthcare programs address cancer in AI communities.

Estrogen induction of telomerase activity through regulation of the mitogen-activated protein kinase (MAPK) dependent pathway in human endometrial cancer cells.

Given that prolonged exposure to estrogen and increased telomerase activity are associated with endometrial carcinogenesis, our objective was to evaluate the interaction between the MAPK pathway and estrogen induction of telomerase activity in endometrial cancer cells. Estradiol (E2) induced telomerase activity and hTERT mRNA expression in the estrogen receptor (ER)-α positive, Ishikawa endometrial cancer cell line. UO126, a highly selective inhibitor of MEK1/MEK2, inhibited telomerase activity and hTERT mRNA expression induced by E2. Similar results were also found after transfection with ERK 1/2-specific siRNA. Treatment with E2 resulted in rapid phosphorylation of p44/42 MAPK and increased MAPK activity which was abolished by UO126. The hTERT promoter contains two estrogen response elements (EREs), and luciferase assays demonstrate that these EREs are activated by E2. Exposure to UO126 or ERK 1/2-specific siRNA in combination with E2 counteracted the stimulatory effect of E2 on luciferase activity from these EREs. These findings suggest that E2-induction of telomerase activity is mediated via the MAPK pathway in human endometrial cancer cells.

Metformin potentiates the effects of paclitaxel in endometrial cancer cells through inhibition of cell proliferation and modulation of the mTOR pathway.

OBJECTIVES: To examine the effects of combination therapy with metformin and paclitaxel in endometrial cancer cell lines. METHODS: ECC-1 and Ishikawa endometrial cancer cell lines were used. Cell proliferation was assessed after exposure to paclitaxel and metformin. Cell cycle progression was assessed by flow cytometry. hTERT expression was determined by real-time RT-PCR. Western immunoblotting was performed to determine the effect of metformin/paclitaxel on the mTOR pathway. RESULTS: Paclitaxel inhibited proliferation in a dose-dependent manner in both cell lines with IC(50) values of 1-5nM and 5-10nM for Ishikawa and ECC-1 cells, respectively. Simultaneous exposure of cells to various doses of paclitaxel in combination with metformin (0.5mM) resulted in a significant synergistic anti-proliferative effect in both cell lines (Combination Index<1). Metformin induced G1 arrest in both cell lines. Paclitaxel alone or in combination with metformin resulted in predominantly G2 arrest. Metformin decreased hTERT mRNA expression while paclitaxel alone had no effect on telomerase activity. Metformin stimulated AMPK phosphorylation and decreased phosphorylation of the S6 protein. In contrast, paclitaxel inhibited AMPK phosphorylation in the ECC-1 cell line and induced phosphorylation of S6 in both cell lines. Treatment with metformin and paclitaxel resulted in decreased phosphorylation of S6 in both cell lines but only had an additive effect on AMPK phosphorylation in the ECC-1 cell line. CONCLUSIONS: Metformin potentiates the effects of paclitaxel in endometrial cancer cells through inhibition of cell proliferation and modulation of the mTOR pathway. This combination may be a promising targeted therapy for endometrial cancer.

Metformin is a potent inhibitor of endometrial cancer cell proliferation--implications for a novel treatment strategy.

OBJECTIVES: Obesity and diabetes are strong risk factors that drive the development of type I endometrial cancers. Recent epidemiological evidence suggests that metformin may lower cancer risk and reduce rates of cancer deaths among diabetic patients. In order to better understand metformin's anti-tumorigenic potential, our goal was to assess the effect of metformin on proliferation and expression of key targets of metformin cell signaling in endometrial cancer cell lines. METHODS: The endometrial cancer cell lines, ECC-1 and Ishikawa, were used. Cell proliferation was assessed after exposure to metformin. Cell cycle progression was evaluated by flow cytometry. Apoptosis was assessed by ELISA for caspase-3 activity. hTERT expression was determined by real-time RT-PCR. Western immunoblotting was performed to determine the expression of the downstream targets of metformin. RESULTS: Metformin potently inhibited growth in a dose-dependent manner in both cell lines (IC(50) of 1 mM). Treatment with metformin resulted in G1 arrest, induction of apoptosis and decreased hTERT expression. Western immunoblot analysis demonstrated that metformin induced phosphorylation of AMPK, its immediate downstream mediator, within 24 h of exposure. In parallel, treatment with metformin decreased phosphorylation of S6 protein, a key target of the mTOR pathway. CONCLUSIONS: We find that metformin is a potent inhibitor of cell proliferation in endometrial cancer cell lines. This effect is partially mediated through AMPK activation and subsequent inhibition of the mTOR pathway. This work should provide the scientific foundation for future investigation of metformin as a strategy for endometrial cancer prevention and treatment.

CXCR1 and CXCR2 activation and regulation. Role of aspartate 199 of the second extracellular loop of CXCR2 in CXCL8-mediated rapid receptor internalization.

CXCL8 (interleukin-8) interacts with two receptors, CXCR1 and CXCR2, to activate leukocytes. Upon activation, CXCR2 internalizes very rapidly relative to CXCR1 ( approximately 90% versus approximately 10% after 5 min). The C termini of the receptors have been shown to be necessary for internalization but are not sufficient to explain the distinct kinetics of down-regulation. To determine the structural determinant(s) that modulate receptor internalization, various chimeric and point mutant receptors were generated by progressively exchanging specific domains or amino acids between CXCR1 and CXCR2. The receptors were stably expressed in rat basophilic leukemia 2H3 cells and characterized for receptor binding, intracellular Ca(2+) mobilization, phosphoinositide hydrolysis, phosphorylation, internalization, and MAPK activation. The data herein indicate that the second extracellular loop (2ECL) of the receptors is critical for the distinct rate of internalization. Replacing the 2ECL of CXCR2 with that of CXCR1 (B(2ECL)A) or Asp(199) with its CXCR1 valine counterpart (B(D199V)A) delayed CXCR2 internalization similarly to CXCR1. Replacing Asp(199) with Asn (B(D199N)) restored CXCR2 rapid internalization. Structure modeling of the 2ECL of the receptors also suggested that Asp(199) plays a critical role in stabilizing and modulating CXCR2 rapid internalization relative to CXCR1. B(D199N) internalized rapidly but migrated as a single phosphorylated form like CXCR1 ( approximately 75 kDa), whereas B(2ECL)A and B(D199V)A showed slow and fast migrating forms like CXCR2 ( approximately 45 and approximately 65 kDa, respectively) but internalized like CXCR1. These data further undermine the role of receptor oligomerization in CXCL8 receptor internalization. Like CXCR1, B(D199V)A also induced sustained ERK activation and cross-desensitized Ca(2+) mobilization to CCR5 relative to B(D199N) and CXCR2. Altogether, the data suggest that the 2ECL of the CXCL8 receptors is important in modulating their distinct rate of down-regulation and thereby signal length and post-internalization activities.