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Background Significant proportion of inflammatory bowel disease (IBD) patients continue to respond inconsistently to therapies, underscoring disease complexity and the need for efficacious treatment. Interleukin 21 (IL‐21), which is known to support T helper (Th) cell function, is highly expressed within inflamed intestinal tissues of IBD patients compared to healthy controls. In addition, inflammatory regulatory T cells (Tregs) have been linked to refractory human IBD. Given that healthy Tregs are critical for self‐tolerance and prevention of IBD, we investigated the metabolic role of IL‐21 in instigating Treg dysfunction and the therapeutic ramifications of targeting metabolism pathways during IBD pathogenesis. Methods Human Tregs as well as relevant control effector Th cells were generated from naïve CD4 + T cells isolated from healthy blood donors. Microarray analysis was utilized for targeted metabolic transcriptional profiling. Immune phenotyping was assessed by fluorescence‐activated cell sorting. Metabolic phenotyping of cells was assessed by Seahorse flux analysis and mass spectrometry‐based metabolomics. Ultrastructural analysis of mitochondria was performed by confocal and transmission electron microscopy. Intestinal inflammation was induced in Rag1 ‐/‐ (T and B cell deficient) mice by the adoptive transfer of pathogenic naïve CD4 + T cells. Results Acute IL‐21 stimulation of human Tregs induced glycolysis and fluctuations in mitochondrial respiration (i.e. oxidative phosphorylation – OXPHOS), as assessed by Seahorse flux analysis. In agreement, microarray analysis, validated by qPCR, revealed an IL‐21‐mediated increase in the expression of genes associated with glycolysis and pathways known to support anabolic and OXPHOS metabolism, thus resembling a hypermetabolic state. Furthermore, IL‐21 stimulation rendered Tregs susceptible to inflammatory response, as evidenced by the production of effector Th cell‐associated cytokines such as interferon γ, tumor necrosis factor, IL‐17A, and IL‐17F. Exploring the mechanisms underlying IL‐21‐induced effects, we found significant disruption of mitochondrial integrity with concomitant activation of glycogen synthase kinase 3 (GSK3) β, a kinase known to prevent pyruvate entry into the mitochondria. IL‐21‐induced GSK3β activation was accompanied by a marked increase in intracellular and extracellular metabolites such as pyruvate and lactate, as assessed by metabolomics. Importantly, GSK3 inhibition or supplementation with mitochondrial membrane‐permeable methyl pyruvate broadly abrogated metabolic wiring of and inflammatory responses by IL‐21‐stimulated Tregs and effector Th cells. Collectively, these results suggest that impaired mitochondrial pyruvate metabolism is a feature of inflammatory CD4 + T cells. Lastly, GSK3 inhibition prevented pathogenic CD4 + T cell‐induced colitis in mice as evidenced by reduced Disease Activity Index, Mouse Colon Histology Index, and serum inflammatory cytokines. Conclusions IL‐21 potently engages human Tregs in a hypermetabolic state that augments inflammatory cytokine production via induction of mitochondrial dysfunction. Therefore desensitizing CD4 + T cells to detrimental cues, such as IL‐21, may also augment Treg function during human IBD.

Neuromuscular dysfunction increases with age and mobility restrictions decrease quality of life for the elderly. A hallmark of aging is the aggregation of proteins and damaged components within a cell, which is especially detrimental to post‐mitotic cells such as motor neurons. Autophagy, a multistep catabolic process, is responsible for the disposal of damaged cellular components. Accumulation of autophagy markers may differ across motor neuron pools consistent with differences in aging effects across muscles. Autophagy is characterized by the elongation of a double‐membrane vacuole around the tagged cargo which fuses with a lysosome and is subsequently degraded. In the present study, expression levels of factors for autophagy initiation (Beclin1), elongation (LC3I, LC3II, the LC3II/I ratio, ATG7, and the ATG5/12 complex), and degradation (p62 clearance) were determined in the cervical (CSC) and lumbar spinal cord (LSC) of male and female C57BL/6 mice at 6, 18, and 24 months of age (n=8/age) using Western blot, spanning a period where aging differences manifest in forelimb vs. hindlimb muscles. A mixed linear model with animal as a random effect was used to compare the effect of age, tissue, sex, and their interaction on the relative expression of each autophagy factor. There was an age*tissue interaction for Beclin1 at 24 mo, with greater Beclin1 expression in LSC than CSC. There was an overall effect of age on LC3I expression, with 24 mo greater than 6 mo, and no changes in LC3II expression. The LC3II/I ratio was significantly different by tissue, whereby CSC had a greater LC3II/I ratio than that of LSC. Expression of ATG7 had a tissue*sex interaction, with ATG7 in females greater in LSC than CSC. There were no changes in ATG5/12 complex. Finally, there was an age and age*tissue interaction in p62 expression. p62 was significantly greater at 24 mo than at 18 mo, and at 18mo the LSC had greater p62 expression than CSC. These results suggest greater impairment of autophagy flux in LSC compared to CSC at comparable ages, consistent with greater susceptibility to aging effects in hindlimb muscles. Future studies will evaluate motor neuron‐specific changes in markers of autophagy elongation (i.e., LC3) and p62 clearance.

Abstract Background The use of menopausal hormone therapy (MHT) may interact with genetic variants to influence colorectal cancer (CRC) risk. Methods We conducted a genome-wide, gene-environment interaction between single nucleotide polymorphisms and the use of any MHT, estrogen only, and combined estrogen-progestogen therapy with CRC risk, among 28 486 postmenopausal women (11 519 CRC patients and 16 967 participants without CRC) from 38 studies, using logistic regression, 2-step method, and 2– or 3–degree-of-freedom joint test. A set-based score test was applied for rare genetic variants. Results The use of any MHT, estrogen only and estrogen-progestogen were associated with a reduced CRC risk (odds ratio [OR] = 0.71, 95% confidence interval [CI] = 0.64 to 0.78; OR = 0.65, 95% CI = 0.53 to 0.79; and OR = 0.73, 95% CI = 0.59 to 0.90, respectively). The 2-step method identified a statistically significant interaction between a GRIN2B variant rs117868593 and MHT use, whereby MHT-associated CRC risk was statistically significantly reduced in women with the GG genotype (OR = 0.68, 95% CI = 0.64 to 0.72) but not within strata of GC or CC genotypes. A statistically significant interaction between a DCBLD1 intronic variant at 6q22.1 (rs10782186) and MHT use was identified by the 2–degree-of-freedom joint test. The MHT-associated CRC risk was reduced with increasing number of rs10782186-C alleles, showing odds ratios of 0.78 (95% CI = 0.70 to 0.87) for TT, 0.68 (95% CI = 0.63 to 0.73) for TC, and 0.66 (95% CI = 0.60 to 0.74) for CC genotypes. In addition, 5 genes in rare variant analysis showed suggestive interactions with MHT (2-sided P < 1.2 × 10−4). Conclusion Genetic variants that modify the association between MHT and CRC risk were identified, offering new insights into pathways of CRC carcinogenesis and potential mechanisms involved.

Abstract Background: Currently known associations between common genetic variants and colorectal cancer explain less than half of its heritability of 25%. As alcohol consumption has a J-shape association with colorectal cancer risk, nondrinking and heavy drinking are both risk factors for colorectal cancer. Methods: Individual-level data was pooled from the Colon Cancer Family Registry, Colorectal Transdisciplinary Study, and Genetics and Epidemiology of Colorectal Cancer Consortium to compare nondrinkers (≤1 g/day) and heavy drinkers (>28 g/day) with light-to-moderate drinkers (1–28 g/day) in GxE analyses. To improve power, we implemented joint 2df and 3df tests and a novel two-step method that modifies the weighted hypothesis testing framework. We prioritized putative causal variants by predicting allelic effects using support vector machine models. Results: For nondrinking as compared with light-to-moderate drinking, the hybrid two-step approach identified 13 significant SNPs with pairwise r2 > 0.9 in the 10q24.2/COX15 region. When stratified by alcohol intake, the A allele of lead SNP rs2300985 has a dose–response increase in risk of colorectal cancer as compared with the G allele in light-to-moderate drinkers [OR for GA genotype = 1.11; 95% confidence interval (CI), 1.06–1.17; OR for AA genotype = 1.22; 95% CI, 1.14–1.31], but not in nondrinkers or heavy drinkers. Among the correlated candidate SNPs in the 10q24.2/COX15 region, rs1318920 was predicted to disrupt an HNF4 transcription factor binding motif. Conclusions: Our study suggests that the association with colorectal cancer in 10q24.2/COX15 observed in genome-wide association study is strongest in nondrinkers. We also identified rs1318920 as the putative causal regulatory variant for the region. Impact: The study identifies multifaceted evidence of a possible functional effect for rs1318920.

Abstract Background The COVID-19 pandemic produced unprecedented demands and rapidly changing evidence and practices within critical care settings. The purpose of this study was to identify factors and strategies that hindered and facilitated effective implementation of new critical care practices and policies in response to the pandemic. Methods We used a cross-sectional, qualitative study design to conduct semi-structured in-depth interviews with critical care leaders across the United States. The interviews were audio-taped and professionally transcribed verbatim. Guided by the Consolidated Framework for Implementation Research (CFIR), three qualitative researchers used rapid analysis methods to develop relevant codes and identify salient themes. Results Among the 17 hospitals that agreed to participate in this study, 31 clinical leaders were interviewed. The CFIR-driven rapid analysis of the interview transcripts generated 12 major themes, which included six implementation facilitators (i.e., factors that promoted the implementation of new critical care practices) and six implementation barriers (i.e., factors that hindered the implementation of new critical care practices). These themes spanned the five CFIR domains (Intervention Characteristics, Outer Setting, Inner Setting, Characteristics of Individuals, and Process) and 11 distinct CFIR constructs. Salient facilitators to implementation efforts included staff resilience, commitment, and innovation, which were supported through collaborative feedback and decision-making mechanisms between leadership and frontline staff. Major identified barriers included lack of access to reliable and transferable information, available resources, uncollaborative leadership and communication styles. Conclusions Through applying the CFIR to organize and synthesize our qualitative data, this study revealed important insights into implementation determinants that influenced the uptake of new critical care practices during COVID-19. As the pandemic continues to burden critical care units, clinical leaders should consider emulating the effective change management strategies identified. The cultivation of streamlined, engaging, and collaborative leadership and communication mechanisms not only supported implementation of new care practices across sites, but it also helped reduce salient implementation barriers, particularly resource and staffing shortages. Future critical care implementation studies should seek to capitalize on identified facilitators and reduce barriers.