KL2 scholars' perceptions of factors contributing to sustained translational science career success.

Introduction: Identifying the most effective ways to support career development of early stage investigators in clinical and translational science should yield benefits for the biomedical research community. Institutions with Clinical and Translational Science Awards (CTSA) offer KL2 programs to facilitate career development; however, the sustained impact has not been widely assessed. Methods: A survey comprised of quantitative and qualitative questions was sent to 2144 individuals that had previously received support through CTSA KL2 mechanisms. The 547 responses were analyzed with identifying information redacted. Results: Respondents held MD (47%), PhD (36%), and MD/PhD (13%) degrees. After KL2 support was completed, physicians' time was divided 50% to research and 30% to patient care, whereas PhD respondents devoted 70% time to research. Funded research effort averaged 60% for the cohort. Respondents were satisfied with their career progression. More than 95% thought their current job was meaningful. Two-thirds felt confident or very confident in their ability to sustain a career in clinical and translational research. Factors cited as contributing to career success included protected time, mentoring, and collaborations. Conclusion: This first large systematic survey of KL2 alumni provides valuable insight into the group's perceptions of the program and outcome information. Former scholars are largely satisfied with their career choice and direction, national recognition of their expertise, and impact of their work. Importantly, they identified training activities that contributed to success. Our results and future analysis of the survey data should inform the framework for developing platforms to launch sustaining careers of translational scientists.

Susceptibility of female rats to cardiac arrhythmias following refeeding after severe food restriction.

BACKGROUND: Many studies have shown malnutrition and inadequate caloric consumption have adverse acute effects on cardiovascular structure and function. METHODS: To determine the adverse long term cardiovascular effects, we studied cardiac morphology and function in female (F) and male (M) severe food restricted rats 3 months after refeeding (sFR-Refed). RESULTS: Two weeks of a normal chow diet in which calories were reduced by 60% decreased body weight (BW) by approximately 15% in both sexes. Within 2 weeks of refeeding, no differences in BW were detected between CT and sFR-Refed groups. However, male rats gained almost 3 times more BW than the females over the 3-month refeeding period. Sex differences were also observed in cardiac pathology. Hearts from F-sFR-Refed rats exhibited more atrophy and less hypertrophy, while M-sFR-Refed rats predominantly exhibited hypertrophic remodeling. While there were no differences in the frequency of ventricular arrhythmias induced by ischemia/reperfusion (I/R) in the isolated heart between M-CT and M-sFR-Refed rats, I/R induced twice as many arrhythmias in the F-sFR-Refed rats compared to F-CT. CONCLUSIONS: These findings indicate the female heart is more susceptible to the long term adverse cardiovascular effects of sFR months after refeeding. Thus, this study provides a rationale for studying sex differences in cardiovascular risk in individuals who experience sFR for voluntary (e.g., very low-calorie dieting) or involuntary (e.g., poverty) reasons earlier in life.

PPAR-α knockout leads to elevated blood pressure response to angiotensin II infusion associated with an increase in renal α-1 Na+/K+ ATPase protein expression and activity.

Peroxisome proliferator activated receptor alpha (PPAR-α) deletion has been shown to increase blood pressure (BP). We hypothesized that the BP increase in PPAR-α KO mice was mediated by increased expression and activity of basolateral Na+/K+ ATPase (NKA) pump. To address this hypothesis, we treated wild-type (WT) and PPAR-α knockout (KO) mice with a slow-pressor dose of angiotensin II (400 ng/kg·min) for 12 days by osmotic minipump. Radiotelemetry showed no significant differences in baseline mean arterial pressure (MAP) between WT and PPAR-α KO mice; however, by day 12 of infusion, MAP was significantly higher in PPAR-α KO mice (156 ± 16) compared to WT mice (138 ± 11 mmHg). NKA activity and protein expression (α1 subunit) were significantly higher in PPAR-α KO mice compared to WT mice. There was no significant difference in NKA mRNA levels. Angiotensin II further increased the expression and activity of the NKA in both genotypes along with the water channel, aquaporin 1 (Aqp1). In contrast, angiotensin II decreased the expression (64-97% reduction in band density) of sodium­hydrogen exchanger-3 (NHE3), NHE regulatory factor-1 (NHERF1, Slc9a3r1), sodium­potassium-2-chloride cotransporter (NKCC2), and epithelial sodium channel (ENaC) ß- and γ- subunits in the renal cortex of both WT and PPAR-α KO mice, with no difference between genotypes. The sodium-chloride cotransporter (NCC) was also decreased by angiotensin II, but significantly more in PPAR-α KO (59% WT versus 77% KO reduction from their respective vehicle-treated mice). Our results suggest that PPAR-α attenuates angiotensin II-mediated increased blood pressure potentially via reducing expression and activity of the NKA.

Clinical and translational science award T32/TL1 training programs: program goals and mentorship practices.

INTRODUCTION: A national survey characterized training and career development for translational researchers through Clinical and Translational Science Award (CTSA) T32/TL1 programs. This report summarizes program goals, trainee characteristics, and mentorship practices. METHODS: A web link to a voluntary survey was emailed to 51 active TL1 program directors and administrators. Descriptive analyses were performed on aggregate data. Qualitative data analysis used open coding of text followed by an axial coding strategy based on the grounded theory approach. RESULTS: Fifty out of 51 (98%) invited CTSA hubs responded. Training program goals were aligned with the CTSA mission. The trainee population consisted of predoctoral students (50%), postdoctoral fellows (30%), and health professional students in short-term (11%) or year-out (9%) research training. Forty percent of TL1 programs support both predoctoral and postdoctoral trainees. Trainees are diverse by academic affiliation, mostly from medicine, engineering, public health, non-health sciences, pharmacy, and nursing. Mentor training is offered by most programs, but mandatory at less than one-third of them. Most mentoring teams consist of two or more mentors. CONCLUSIONS: CTSA TL1 programs are distinct from other NIH-funded training programs in their focus on clinical and translational research, cross-disciplinary approaches, emphasis on team science, and integration of multiple trainee types. Trainees in nearly all TL1 programs were engaged in all phases of translational research (preclinical, clinical, implementation, public health), suggesting that the CTSA TL1 program is meeting the mandate of NCATS to provide training to develop the clinical and translational research workforce.

Educational initiative in an NCATS TL1 training program to address the impact of systemic racism on human health, biomedical research, and the translational scientist.

Introduction: The goal of clinical and translational science (CTS) is to fill gaps in medical knowledge toward improving human health. However, one of our most pressing challenges does not reside within the biological map we navigate to find sustainable cures but rather the moral compass to recognize and overcome racial and ethnic injustices that continue to influence our society and hinder diverse research rigor. The Georgetown-Howard Universities Center for Clinical and Translational Science includes an inter-institutional TL1-funded training program for predoctoral/postdoctoral trainees in Translational Biomedical Science (TBS). Methods: In the fall of 2020, the TBS program responded to the national social justice crisis by incorporating a curriculum focused on structural racism in biomedical research. Educational platforms, including movie reviews, Journal Clubs, and other workshops, were threaded throughout the curriculum by ensuring safe spaces to discuss racial and ethnic injustices and providing trainees with practical steps to recognize, approach, and respond to these harmful biases in the CTS. Workshops also focused on why individuals underrepresented in science are vital for addressing and closing gaps in CTS. Results: Paring analysis using REDCap software de-identified participants after invitations were sent and collected in the system to maintain anonymity for pre- and post-analysis. The Likert scale evaluated respondents' understanding of diverse scientific circumstances. The pre/Fall and post/Spring surveys suggested this curriculum was successful at raising institutional awareness of racial and ethnic biases. Evaluating the effectiveness of our program with other training Clinical and Translational Science Awards (CTSA) consortiums will strengthen both the academic and professional TBS programs.

Caloric Restriction and Cardiovascular Health: the Good, the Bad, and the Renin-Angiotensin System.

Much excitement exists over the cardioprotective and life-extending effects of caloric restriction (CR). This review integrates population studies with experimental animal research to address the positive and negative impact of mild and severe CR on cardiovascular physiology and pathophysiology, with a particular focus on the renin-angiotensin system (RAS). We also highlight the gaps in knowledge and areas ripe for future physiological research.

Preliminary study of ovariectomy and chronic losartan-induced alterations in brain AT1 receptors.

Women who undergo oophorectomy prior to the age of natural menopause have a higher risk of neurological and psychological impairment. Treatment with the angiotensin receptor blocker (ARB) losartan for 10 weeks following ovariectomy of Long-Evans rats at 3 months of age reduced the ovariectomy-induced cognitive decrements. Following completion of the behavioral experiments, (Campos et al., 2019), the brains were harvested for preliminary receptor autoradiographic studies of AT1 receptor (AT1R) binding in selected brain regions using quantitative densitometric analysis of autoradiograms of 125I-sarcosine1, isoleucine8 angiotensin II binding. Four of the brain regions (amygdala, ventral subiculum, piriform cortex, and cingulate cortex) are associated with cognitive and emotional behavior while one (lateral hypothalamus) is associated with homeostasis. The density of AT1R varied by region: ventral subiculum > amygdala and cingulate cortex, and piriform cortex > cingulate cortex. Losartan treatment decreased AT1R binding in the ventral subiculum of sham and ovariectomized rats by 41.6%, and 46% in the piriform cortex of the sham rats, but tended to increase AT1R binding in the piriform cortex and cingulate cortex 77% and 107%, respectively, in the ovariectomized rats. AT1R binding did not differ significantly between intact male and sham-vehicle female rats among surveyed brain regions. These results suggest that losartan-induced changes in brain AT1R expression may contribute to the reduced anxiety-like behavior and memory impairments seen in ovariectomized rats, but replication of these observations will be needed to determine the extent to which brain AT1R changes mediate the adverse behavioral effects of ovariectomy.

Male bias in ACE2 basic science research: missed opportunity for discovery in the time of COVID-19.

Throughout the world, including the United States, men have worse outcomes from COVID-19 than women. SARS-CoV-2, the causative virus of the COVID-19 pandemic, uses angiotensin-converting enzyme 2 (ACE2) to gain cellular entry. ACE2 is a member of the renin-angiotensin system (RAS) and plays an important role in counteracting the harmful effects mediated by the angiotensin type 1 receptor. Therefore, we conducted Ovid MEDLINE and Embase database searches of basic science studies investigating the impact of the biological variable of sex on ACE2 expression and regulation from 2000, the year ACE2 was discovered, through December 31, 2020. Out of 2,131 publications, we identified 853 original research articles on ACE2 conducted in primary cells, tissues, and/or whole mammals excluding humans. The majority (68.7%) of these studies that cited the sex of the animal were conducted in males, while 11.2% were conducted solely in females; 9.26% compared ACE2 between the sexes, while 10.8% did not report the sex of the animals used. General findings are that sex differences are tissue-specific and when present, are dependent upon gonadal state. Renal, cardiac, and adipose ACE2 is increased in both sexes under experimental conditions that model co-morbidities associated with worse COVID-19 outcomes including hypertension, obesity, and renal and cardiovascular diseases; however, ACE2 protein was generally higher in the males. Studies in Ace2 knockout mice indicate ACE2 plays a greater role in protecting the female from developing hypertension than the male. Studying the biological variable of sex in ACE2 research provides an opportunity for discovery in conditions involving RAS dysfunction and will shed light on sex differences in COVID-19 severity.

Modulation of the rat angiotensin type 1a receptor by an upstream short open reading frame.

The rat angiotensin type 1a receptor (AT1aR) is a peptide hormone G protein-coupled receptor (GPCR) that plays a key role in electrolyte homeostasis and blood pressure control. There is a highly conserved short open reading frame (sORF) in exon 2 (E2) that is downstream from exon 1 (E1) and upstream of the AT1aR coding region located in exon 3 (E3). To determine the role of this E2 sORF in AT1aR signaling, human embryonic kidney-293 (HEK293) cells were transfected with plasmids containing AT1aR cDNA with either an intact or disrupted E2 sORF. The intact sORF attenuated the efficacy of angiotensin (Ang) II (p < 0.001) and sarcosine1,Ile4,Ile8-Ang II (SII), (p < 0.01) to activate AT1aR signaling through extracellular signal-related kinases 1/2 (ERK1/2). A time-course showed agonist-induced AT1aR-mediated ERK1/2 activation was slower in the presence of the intact compared to the disrupted sORF [Ang II: p < 0.01 and SII: p < 0.05]. Ang II-induced ERK1/2 activation was completely inhibited by the protein kinase C (PKC) inhibitor Ro 31-8220 regardless of whether the sORF was intact or disrupted. Flow cytometric analyses suggested the intact sORF improved cell survival; the percentage of live cells increased (p < 0.05) while the percentage of early apoptotic cells decreased (p < 0.01) in cells transfected with the AT1aR plasmid containing the intact sORF. These findings have implications for the regulation of AT1Rs in physiological and pathological conditions and warrant investigation of sORFs in the 5' leader sequence (5'LS) of other GPCRs.