Evaluating the efficacy of vatiquinone in preclinical models of mitochondrial disease.

Background: Genetic mitochondrial diseases are a major challenge in modern medicine, impacting around 1:4,000 individuals. Leigh syndrome is the most common pediatric presentation of mitochondrial disease. There are currently no effective clinical treatments for mitochondrial disease. In humans, patients are often treated with antioxidants, vitamins, and strategies targeting energetics. The vitamin-E related compound vatiquinone (EPI-743, α-tocotrienol quinone) has been the subject of at least 19 clinical trials in the US since 2012, but the effects of vatiquinone on an animal model of mitochondrial disease have not yet been reported. Here, assessed the impact of vatiquinone on disease progression and in two animal models of mitochondrial disease. Methods: The efficacy of vatiquinone in vitro was assessed using human fibroblasts treated with the general mitochondrial oxidative stress inducer paraquat, the GPX4 inhibitor RSL3, or the glutathione synthase inhibitor BSO in combination with excess iron. The therapeutic potential of vatiquinone in vivo was assessed using tamoxifen-induced mouse model for GPX4 deficiency and the Ndufs4 knockout mouse model of Leigh syndrome. In both models, animals were treated daily with vatiquinone or vehicle and relevant disease endpoints were assessed. Results: Vatiquinone robustly prevented death in cultured cells induced by RSL3 or BSO/iron, but had no effect on paraquat induced cell death. Vatiquinone had no impact on disease onset, progression, or survival in either the tamoxifen-inducible GPX4 deficient model or the Ndufs4(-/-) mouse model, though the drug may have reduced seizure risk. Conclusions: Vatiquinone provided no benefit to survival in two mouse models of disease, but may prevent seizures in the Ndufs4(-/-) model. Our findings are consistent with recent press statements regarding clinical trial results and have implications for drug trial design and reporting in patients with rare diseases.

Reduction of specific enterocytes from loss of intestinal LGR4 improves lipid metabolism in mice.

Whether intestinal Leucine-rich repeat containing G-protein-coupled receptor 4 (LGR4) impacts nutrition absorption and energy homeostasis remains unknown. Here, we report that deficiency of Lgr4 (Lgr4iKO) in intestinal epithelium decreased the proportion of enterocytes selective for long-chain fatty acid absorption, leading to reduction in lipid absorption and subsequent improvement in lipid and glucose metabolism. Single-cell RNA sequencing demonstrates the heterogeneity of absorptive enterocytes, with a decrease in enterocytes selective for long-chain fatty acid-absorption and an increase in enterocytes selective for carbohydrate absorption in Lgr4iKO mice. Activation of Notch signaling and concurrent inhibition of Wnt signaling are observed in the transgenes. Associated with these alterations is the substantial reduction in lipid absorption. Decrement in lipid absorption renders Lgr4iKO mice resistant to high fat diet-induced obesity relevant to wild type littermates. Our study thus suggests that targeting intestinal LGR4 is a potential strategy for the intervention of obesity and liver steatosis.

Interferon-gamma contributes to disease progression in the Ndufs4(-/-) model of Leigh syndrome.

AIM: Leigh syndrome (LS), the most common paediatric presentation of genetic mitochondrial dysfunction, is a multi-system disorder characterised by severe neurologic and metabolic abnormalities. Symmetric, bilateral, progressive necrotizing lesions in the brainstem are defining features of the disease. Patients are often symptom free in early life but typically develop symptoms by about 2 years of age. The mechanisms underlying disease onset and progression in LS remain obscure. Recent studies have shown that the immune system causally drives disease in the Ndufs4(-/-) mouse model of LS: treatment of Ndufs4(-/-) mice with the macrophage-depleting Csf1r inhibitor pexidartinib prevents disease. While the precise mechanisms leading to immune activation and immune factors involved in disease progression have not yet been determined, interferon-gamma (IFNγ) and interferon gamma-induced protein 10 (IP10) were found to be significantly elevated in Ndufs4(-/-) brainstem, implicating these factors in disease. Here, we aimed to explore the role of IFNγ and IP10 in LS. METHODS: To establish the role of IFNγ and IP10 in LS, we generated IFNγ and IP10 deficient Ndufs4(-/-)/Ifng(-/-) and Ndufs4(-/-)/IP10(-/-) double knockout animals, as well as IFNγ and IP10 heterozygous, Ndufs4(-/-)/Ifng(+/-) and Ndufs4(-/-)/IP10(+/-), animals. We monitored disease onset and progression to define the impact of heterozygous or homozygous loss of IFNγ and IP10 in LS. RESULTS: Loss of IP10 does not significantly impact the onset or progression of disease in the Ndufs4(-/-) model. IFNγ loss significantly extends survival and delays disease progression in a gene dosage-dependent manner, though the benefits are modest compared to Csf1r inhibition. CONCLUSIONS: IFNγ contributes to disease onset and progression in LS. Our findings suggest that IFNγ targeting therapies may provide some benefits in genetic mitochondrial disease, but targeting IFNγ alone would likely yield only modest benefits in LS.

Intermittent fasting promotes type 3 innate lymphoid cells secreting IL-22 contributing to the beigeing of white adipose tissue.

Mechanism underlying the metabolic benefit of intermittent fasting remains largely unknown. Here, we reported that intermittent fasting promoted interleukin-22 (IL-22) production by type 3 innate lymphoid cells (ILC3s) and subsequent beigeing of subcutaneous white adipose tissue. Adoptive transfer of intestinal ILC3s increased beigeing of white adipose tissue in diet-induced-obese mice. Exogenous IL-22 significantly increased the beigeing of subcutaneous white adipose tissue. Deficiency of IL-22 receptor (IL-22R) attenuated the beigeing induced by intermittent fasting. Single-cell sequencing of sorted intestinal immune cells revealed that intermittent fasting increased aryl hydrocarbon receptor signaling in ILC3s. Analysis of cell-cell ligand receptor interactions indicated that intermittent fasting may stimulate the interaction of ILC3s with dendritic cells and macrophages. These results establish the role of intestinal ILC3s in beigeing of white adipose tissue, suggesting that ILC3/IL-22/IL-22R axis contributes to the metabolic benefit of intermittent fasting.

Obesity refers to a condition where a person has excessive fat accumulation, which can have negative impacts on their health. Managing obesity has typically relied on reducing energy intake and increasing energy use through diets and exercise. For example, intermittent fasting is a diet strategy involving periods of time in a day or week where a person does not eat any food. Research has shown that intermittent fasting may improve the metabolism and increase energy use by enhancing a process known as "beigeing" of white fat tissue. In this process, white fat cells or their precursor cells differentiate into beige fat cells, which can consume excess energy by burning fat. Consequently, understanding how beigeing of white fat cells is activated in intermittent fasting may reveal a promising strategy for tackling obesity and metabolic diseases. Immune cells found in the gut known as innate lymphoid cells (ILCs) may play a role in the metabolic benefits from intermittent fasting. However, the roles of ILCs are complex: some types of ILCs can promote obesity, while others show metabolic benefits through their release of proteins like IL-17 and IL-22, which can help the body to metabolise glucose. To find out if these immune cells play a role in intermittent fasting, Chen, Sun et al. used diet-induced obese mice that had to fast every other day. Intermittent fasting was found to cause a form of ILCs (ILC3s) to release IL-22, which resulted in beigeing of white fat cells in obese mice. Single-cell sequencing techniques of gut immune cells further revealed that intermittent fasting increased forms of signalling in ILC3s and caused ILC3s to interact with other immune cells, such as dendritic cells and macrophages. The findings demonstrate how intermittent fasting causes beigeing of white adipose tissue through ILC3s, revealing mechanisms underpinning the metabolic benefits found from intermittent fasting. More research into this process may help identify new targets for treating obesity.

Hepatic LGR4 aggravates cholestasis-induced liver injury in mice.

Current therapy for hepatic injury induced by the accumulation of bile acids is limited. Leucine-rich repeat G protein-coupled receptor 4 (LGR4), also known as GPR48, is critical for cytoprotection and cell proliferation. Here, we reported a novel function for the LGR4 in cholestatic liver injury. In the bile duct ligation (BDL)-induced liver injury model, hepatic LGR4 expression was significantly downregulated. Deficiency of LGR4 in hepatocytes (Lgr4LKO) notably decreased BDL-induced liver injury measured by hepatic necrosis, fibrosis, and circulating liver enzymes and total bilirubin. Levels of total bile acids in plasma and liver were markedly reduced in these mice. However, deficiency of LGR4 in macrophages (Lyz2-Lgr4MKO) demonstrated no significant effect on liver injury induced by BDL. Deficiency of LGR4 in hepatocytes significantly attenuated S1PR2 and the phosphorylation of protein kinase B (AKT) induced by BDL. Recombinant Rspo1 and Rspo3 potentiated the taurocholic acid (TCA)-induced upregulation in S1PR2 and phosphorylation of AKT in hepatocytes. Inhibition of S1PR2-AKT signaling by specific AKT or S1PR2 inhibitors blocked the increase of bile acid secretion induced by Rspo1/3 in hepatocytes. Our studies indicate that the R-spondins (Rspos)-LGR4 signaling in hepatocytes aggravates the cholestatic liver injury by potentiating the production of bile acids in a S1PR2-AKT-dependent manner.NEW & NOTEWORTHY Deficiency of LGR4 in hepatocytes alleviates BDL-induced liver injury. LGR4 in macrophages demonstrates no effect on BDL-induced liver injury. Rspos-LGR4 increases bile acid synthesis and transport via potentiating S1PR2-AKT signaling in hepatocytes.

Impact of dietary ketosis on volatile anesthesia toxicity in a model of Leigh syndrome.

BACKGROUND: Genetic mitochondrial diseases impact over 1 in 4000 individuals, most often presenting in infancy or early childhood. Seizures are major clinical sequelae in some mitochondrial diseases including Leigh syndrome, the most common pediatric presentation of mitochondrial disease. Dietary ketosis has been used to manage seizures in mitochondrial disease patients. Mitochondrial disease patients often require surgical interventions, leading to anesthetic exposures. Anesthetics have been shown to be toxic in the setting of mitochondrial disease, but the impact of a ketogenic diet on anesthetic toxicities in this setting has not been studied. AIMS: Our aim in this study was to determine whether dietary ketosis impacts volatile anesthetic toxicities in the setting of genetic mitochondrial disease. METHODS: The impact of dietary ketosis on toxicities of volatile anesthetic exposure in mitochondrial disease was studied by exposing young Ndufs4(-/-) mice fed ketogenic or control diet to isoflurane anesthesia. Blood metabolites were measured before and at the end of exposures, and survival and weight were monitored. RESULTS: Compared to a regular diet, the ketogenic diet exacerbated hyperlactatemia resulting from isoflurane exposure (control vs. ketogenic diet in anesthesia mean difference 1.96 mM, Tukey's multiple comparison adjusted p = .0271) and was associated with a significant increase in mortality during and immediately after exposures (27% vs. 87.5% mortality in the control and ketogenic diet groups, respectively, during the exposure period, Fisher's exact test p = .0121). Our data indicate that dietary ketosis and volatile anesthesia interact negatively in the setting of mitochondrial disease. CONCLUSIONS: Our findings suggest that extra caution should be taken in the anesthetic management of mitochondrial disease patients in dietary ketosis.

Rspo2-LGR4 exacerbates hepatocellular carcinoma progression via activation of Wnt/ß-catenin signaling pathway.

BACKGROUND: The leucine-rich repeat-containing G-protein-coupled receptor 4 (LGR4) plays an important role in stem cell differentiation, organ development and cancer. Whether LGR4 affects the progression of hepatocellular carcinoma (HCC) remains unknown. This study aimed to reveal the role of LGR4 in HCC. METHODS: Clinical samples of HCC were collected to assess the expression of LGR4 and its correlation with patients' clinical characteristics. The expression level of LGR4 in HCC cells was altered by pharmacological and genetic methods, and the role of LGR4 in HCC progression was analyzed by in vivo and in vitro assays. HCC was induced by diethylnitrosamine (DEN) and carbon tetrachloride (CCl4) in wild-type and LGR4 deficient mice, the effect of LGR4 on HCC was examined by histopathological evaluation and biochemical assays. RESULTS: LGR4 expression was up-regulated in HCC samples, and its expression level was positively correlated with tumor size, microvascular invasion (MVI), TNM stage and pathological differentiation grade of HCC patients. In the mouse HCC model induced by DEN+CCl4, knockdown of LGR4 effectively inhibited the progression of HCC. Silencing of LGR4 inhibited the proliferation, migration, invasion, stem cell-like properties and Warburg effect of HCC cells. These phenotypes were promoted by R-spondin2 (Rspo2), an endogenous ligand for LGR4. Rspo2 markedly increased the nuclear translocation of ß-catenin, whereas IWR-1, an inhibitor of Wnt/ß-catenin signaling, reversed its effect. Deficiency of LGR4 significantly reduced the nuclear translocation of ß-catenin and the expression of its downstream target genes cyclinD1 and c-Myc. CONCLUSIONS: LGR4 promotes HCC progression via Wnt/ß-catenin signaling pathway.

Intermittent fasting promotes ILC3s secreting IL-22 contributing to the beigeing of white adipose tissue.

Mechanism underlying the metabolic benefit of intermittent fasting remains largely unknown. Here, we reported that intermittent fasting promoted IL-22 production by ILC3s and subsequent beigeing of subcutaneous white adipose tissue. Adoptive transfer of intestinal ILC3s increased beigeing of white adipose tissue in diet-induced-obese mice. Exogenous IL-22 significantly increased the beigeing of subcutaneous white adipose tissue. Deficiency of IL-22 receptor attenuated the beigeing induced by intermittent fasting. Single-cell sequencing of sorted intestinal immune cells revealed that intermittent fasting increased aryl hydrocarbon receptor signaling in ILC3s. Analysis of cell‒cell ligand receptor interactions indicated that intermittent fasting may stimulate the interaction of ILC3s with dendritic cells (DCs) and macrophages. These results establish the role of intestinal ILC3s in beigeing of white adipose tissue, suggesting that ILC3/IL-22/IL-22R axis contributes to the metabolic benefit of intermittent fasting.

Nuclear Acly protects the liver from ischemia-reperfusion injury.

BACKGROUND AND AIMS: Hepatic ischemia-reperfusion (IR) injury is the most common complication that occurs in liver surgery and hemorrhagic shock. ATP citrate lyase (Acly) plays a pivotal role in chromatin modification via generating acetyl-CoA for histone acetylation to influence biological processes. We aim to examine the roles of Acly, which is highly expressed in hepatocytes, in liver IR injury. APPROACH AND RESULTS: The functions of Acly in hepatic IR injury were examined in the mouse model with a hepatocyte-specific knockout of Acly . The Acly target genes were analyzed by CUT&RUN assay and RNA sequencing. The relationship between the susceptibility of the steatotic liver to IR and Acly was determined by the gain of function studies in mice. Hepatic deficiency of Acly exacerbated liver IR injury. IR induced Acly nuclear translocation in hepatocytes, which spatially fueled nuclear acetyl-CoA. This alteration was associated with enhanced acetylation of H3K9 and subsequent activation of the Foxa2 signaling pathway. Nuclear localization of Acly enabled Foxa2-mediated protective effects after hypoxia-reperfusion in cultured hepatocytes, while cytosolic Acly demonstrated no effect. The presence of steatosis disrupted Acly nuclear translocation. In the steatotic liver, restoration of Acly nuclear localization through overexpression of Rspondin-1 or Rspondin-3 ameliorated the IR-induced injury. CONCLUSIONS: Our results indicate that Acly regulates histone modification by means of nuclear AcCoA production in hepatic IR. Disruption of Acly nuclear translocation increases the vulnerability of the steatotic liver to IR. Nuclear Acly thus may serve as a potential therapeutic target for future interventions in hepatic IR injury, particularly in the context of steatosis.

Volatile anaesthetic toxicity in the genetic mitochondrial disease Leigh syndrome.

BACKGROUND: Volatile anaesthetics are widely used in human medicine. Although generally safe, hypersensitivity and toxicity can occur in rare cases, such as in certain genetic disorders. Anaesthesia hypersensitivity is well-documented in a subset of mitochondrial diseases, but whether volatile anaesthetics are toxic in this setting has not been explored. METHODS: We exposed Ndufs4(-/-) mice, a model of Leigh syndrome, to isoflurane (0.2-0.6%), oxygen 100%, or air. Cardiorespiratory function, weight, blood metabolites, and survival were assessed. We exposed post-symptom onset and pre-symptom onset animals and animals treated with the macrophage depleting drug PLX3397/pexidartinib to define the role of overt neuroinflammation in volatile anaesthetic toxicities. RESULTS: Isoflurane induced hyperlactataemia, weight loss, and mortality in a concentration- and duration-dependent manner from 0.2% to 0.6% compared with carrier gas (O2 100%) or mock (air) exposures (lifespan after 30-min exposures ∗P<0.05 for isoflurane 0.4% vs air or vs O2, ∗∗P<0.005 for isoflurane 0.6% vs air or O2; 60-min exposures ∗∗P<0.005 for isoflurane 0.2% vs air, ∗P<0.05 for isoflurane 0.2% vs O2). Isoflurane toxicity was significantly reduced in Ndufs4(-/-) exposed before CNS disease onset, and the macrophage depleting drug pexidartinib attenuated sequelae of isoflurane toxicity (survival ∗∗∗P=0.0008 isoflurane 0.4% vs pexidartinib plus isoflurane 0.4%). Finally, the laboratory animal standard of care of 100% O2 as a carrier gas contributed significantly to weight loss and reduced survival, but not to metabolic changes, and increased acute mortality. CONCLUSIONS: Isoflurane is toxic in the Ndufs4(-/-) model of Leigh syndrome. Toxic effects are dependent on the status of underlying neurologic disease, largely prevented by the CSF1R inhibitor pexidartinib, and influenced by oxygen concentration in the carrier gas.

Glutamine metabolism in diseases associated with mitochondrial dysfunction.

Mitochondrial dysfunction can arise from genetic defects or environmental exposures and impact a wide range of biological processes. Among these are metabolic pathways involved in glutamine catabolism, anabolism, and glutamine-glutamate cycling. In recent years, altered glutamine metabolism has been found to play important roles in the pathologic consequences of mitochondrial dysfunction. Glutamine is a pleiotropic molecule, not only providing an alternate carbon source to glucose in certain conditions, but also playing unique roles in cellular communication in neurons and astrocytes. Glutamine consumption and catabolic flux can be significantly altered in settings of genetic mitochondrial defects or exposure to mitochondrial toxins, and alterations to glutamine metabolism appears to play a particularly significant role in neurodegenerative diseases. These include primary mitochondrial diseases like Leigh syndrome (subacute necrotizing encephalopathy) and MELAS (mitochondrial myopathy with encephalopathy, lactic acidosis, and stroke-like episodes), as well as complex age-related neurodegenerative disorders such as Alzheimer's and Parkinson's diseases. Pharmacologic interventions targeting glutamine metabolizing and catabolizing pathways appear to provide some benefits in cell and animal models of these diseases, indicating glutamine metabolism may be a clinically relevant target. In this review, we discuss glutamine metabolism, mitochondrial disease, the impact of mitochondrial dysfunction on glutamine metabolic processes, glutamine in neurodegeneration, and candidate targets for therapeutic intervention.

Peripheral macrophages drive CNS disease in the Ndufs4(-/-) model of Leigh syndrome.

Subacute necrotizing encephalopathy, or Leigh syndrome (LS), is the most common pediatric presentation of genetic mitochondrial disease. LS is a multi-system disorder with severe neurologic, metabolic, and musculoskeletal symptoms. The presence of progressive, symmetric, and necrotizing lesions in the brainstem are a defining feature of the disease, and the major cause of morbidity and mortality, but the mechanisms underlying their pathogenesis have been elusive. Recently, we demonstrated that high-dose pexidartinib, a CSF1R inhibitor, prevents LS CNS lesions and systemic disease in the Ndufs4(-/-) mouse model of LS. While the dose-response in this study implicated peripheral immune cells, the immune populations involved have not yet been elucidated. Here, we used a targeted genetic tool, deletion of the colony-stimulating Factor 1 receptor (CSF1R) macrophage super-enhancer FIRE (Csf1rΔFIRE), to specifically deplete microglia and define the role of microglia in the pathogenesis of LS. Homozygosity for the Csf1rΔFIRE allele ablates microglia in both control and Ndufs4(-/-) animals, but onset of CNS lesions and sequalae in the Ndufs4(-/-), including mortality, are only marginally impacted by microglia depletion. The overall development of necrotizing CNS lesions is not altered, though microglia remain absent. Finally, histologic analysis of brainstem lesions provides direct evidence of a causal role for peripheral macrophages in the characteristic CNS lesions. These data demonstrate that peripheral macrophages play a key role in the pathogenesis of disease in the Ndufs4(-/-) model.

Reflections on a leadership development program: Impacts on culture in a surgical environment.

BACKGROUND: Although a growing body of literature has focused on the impacts leadership development programs have had on the individual surgeon, little effort has been focused on understanding the impacts these programs have had on surgical culture. The purpose of this study was to explore the impacts of implementing a leadership development program on the culture of the Department of Surgery at University of Michigan, Ann Arbor. METHODS: Qualitative interviews were conducted with 14 surgery faculty in the first cohort of a leadership development program at University of Michigan. Using NVivo (version 11.4.3; QSR International, Melbourne, Australia), thematic analysis was used to locate, analyze, and report patterns within the data. RESULTS: Thematic analysis demonstrated that participation in a leadership development program influenced surgical culture in the following ways: (1) promoted a more participative leadership style, providing tools for surgeons to create a more collaborative environment; (2) increased the culture of diversity, with leaders in the department valuing a more inclusive and wide range of skill sets; and (3) strengthened the collegial environment as evidenced by improved morale and relationships within the department. In addition, several participants expressed difficulty in teasing out what was a direct benefit of a leadership development program versus what could be attributable to other factors, referred to here as the chicken or egg argument. CONCLUSION: Almost all participants expressed experiencing at least some change that they believed was related to the leadership development program. This research may provide insight into the broader implications that programs like these have on surgical culture.

Outcomes of Endoscopic Surveillance in Individuals With Genetic Predisposition to Hereditary Diffuse Gastric Cancer.

BACKGROUND & AIMS: Pathogenic germline variants in CDH1 are associated with risk for diffuse gastric cancer (DGC) and lobular breast cancer. The reported high incidence of DGC and limited sensitivity of endoscopy in detection have prompted recommendation for total prophylactic gastrectomy for carriers of pathogenic or likely pathogenic (PLP) germline variants of CDH1. Multigene panel tests have identified increasing numbers of carriers of PLP variants in CDH1 who lack a family history of DGC. We evaluated outcomes of endoscopic surveillance for carriers of PLP variants of CDH1 with and without family history of DGC. METHODS: Individuals from 13 families with germline PLP variants of CDH1 were evaluated at the Michigan Medicine Cancer Genetics Clinic from January 1998 through May 2018. Outcomes of esophagogastroduodenoscopy examinations, histopathology analyses, and surgery were compared between individuals with and without a family history of DGC. RESULTS: We identified 20 carriers of germline CDH1 PLP variants; they underwent endoscopic examinations and/or gastrectomy. None had abnormal findings visible during endoscopy. Signet ring cell carcinoma (SRCC) was detected in 12 of 20 subjects. All but 1 of the carcinomas were tiny and confined to the lamina propria, and 1 was transmural. Seven of 12 subjects who had SRCC reported no diagnoses of DGC in first-degree relatives and did not meet established criteria for CDH1 analysis based on a 3-generation family pedigree. CONCLUSIONS: More than half of individuals with germlines variants of CDH1 that are PLP had histopathologic evidence for DGC on endoscopy and/or gastrectomy. Family history of DGC and endoscopic findings therefore do not appear to be reliable determinants of risk of SRCC in individuals with genetic predisposition to DGC.

Eliminating Institutional Barriers to Career Advancement for Diverse Faculty in Academic Surgery.

: There is critical need to address achievement barriers in Academic Medicine. Although opportunities for professional development of women and underrepresented minority physician scientists are growing, academic promotion rates remain historically low. Moreover, underrepresented groups are not likely to advance to decanal and leadership positions. To eliminate institutional barriers to achievement for diverse faculty, strategies to strengthen environment, recruitment, professional development, and leadership were implemented. This multifaceted approach is adaptable to Academic Surgery universally and we wish to share early progress.

Building High-Performing Teams in Academic Surgery: The Opportunities and Challenges of Inclusive Recruitment Strategies.

PROBLEM: In academic surgery, women and physicians from ethnic minority groups remain inadequately represented relative to their representation in the U.S. population and among medical students and surgical trainees. Although several initiatives have been aimed at developing the academic surgery pipeline or addressing issues related to faculty retention and promotion, little is known about how recruitment practices impact diversity in academic medicine. Moreover, national standards and ideal practices specific for effective recruitment in surgery have not been established. APPROACH: A working group at the Department of Surgery at the University of Michigan implemented an inclusive search and selection process for all open faculty positions within the department in academic year 2017-2018. The strategy included mandatory training, a standing recruitment committee with diverse membership, broad promotion of positions, implementing a modified "Rooney rule," panel interviews of candidates, standardized interview protocols, a standardized evaluation tool and scoring system, and written evaluations/ranking of candidates. OUTCOMES: Implementation of this recruitment strategy resulted in several immediate measurable benefits including increased diversity of the applicant pools and of new faculty hires. In addition to these positive effects, the department noted several knowledge gaps and faced challenges to implementing all elements of the strategy. NEXT STEPS: The authors share their framework, highlighting opportunities and challenges that are broadly generalizable and relevant for building high-performing teams in academic medicine. Work to set measurable metrics and address challenges for inclusive recruitment in surgery is ongoing. Such evaluation and refinement are important for sustainability and increasing effectiveness.

mTOR Signaling in X/A-Like Cells Contributes to Lipid Homeostasis in Mice.

Gastric mechanistic target of rapamycin (mTOR) signaling is inversely associated with the expression and secretion of ghrelin, a 28-aa peptide hormone produced by gastric X/A-like cells. Ghrelin contributes to obesity and hepatic steatosis. We sought to control global lipid metabolism via the manipulation of gastric mTOR signaling in X/A-like cells. We established a ghrl-cre transgene in which the Cre enzyme is expressed in X/A-like cells under the control of the ghrelin-promoter. mTORflox/flox and tuberous sclerosis 1 (TSC1)flox/flox mice were separately bred with ghrl-cre mice to generate mTOR-ghrl-cre or TSC1-ghrl-cre mice, within which mTOR signaling was suppressed or activated, respectively. Lipid metabolism in liver and adipose depots was analyzed. Under the control of the ghrelin-promoter, the Cre enzyme was exclusively expressed in stomach X/A-like cells in adult animals. Knockout of mTOR in X/A-like cells increased circulating acyl-ghrelin and promoted hepatic lipogenesis with effects on adipose depots. Activation of mTOR signaling by deletion of its upstream inhibitor, TSC1, decreased ghrelin expression and secretion, altering lipid metabolism as evidenced by resistance to high-fat diet-induced obesity and hepatic steatosis. Both ghrelin administration and injection of rapamycin, an inhibitor of mTOR, altered the phenotypes of TSC1-ghrl-cre mice. Conclusion: Gastric mTOR signaling in X/A-like cells contributes to organism lipid homeostasis by regulating hepatic and adipose lipid metabolism. Gastric mTOR signaling may provide an alternative strategy for intervention in lipid disorders.