Critical role of thrombospondin-1 in promoting intestinal mucosal wound repair.

Thrombospondin-1 (TSP1) is a matricellular protein associated with the regulation of cell migration through direct binding interactions with integrin proteins and by associating with other receptors known to regulate integrin function, including CD47 and CD36. We previously demonstrated that deletion of an epithelial TSP1 receptor, CD47, attenuates epithelial wound repair following intestinal mucosal injury. However, the mechanisms by which TSP1 contributes to intestinal mucosal repair remain poorly understood. Our results show upregulated TSP1 expression in colonic mucosal wounds and impaired intestinal mucosal wound healing in vivo upon intestinal epithelium-specific loss of TSP1 (VillinCre/+ Thbs1fl/fl or Thbs1ΔIEC mice). We report that exposure to exogenous TSP1 enhanced migration of intestinal epithelial cells in a CD47- and TGF-ß1-dependent manner and that deficiency of TSP1 in primary murine colonic epithelial cells resulted in impaired wound healing. Mechanistically, TSP1 modulated epithelial actin cytoskeletal dynamics through suppression of RhoA activity, activation of Rho family small GTPase (Rac1), and changes in filamentous-actin bundling. Overall, TSP1 was found to regulate intestinal mucosal wound healing via CD47 and TGF-ß1, coordinate integrin-containing cell-matrix adhesion dynamics, and remodel the actin cytoskeleton in migrating epithelial cells to enhance cell motility and promote wound repair.

Circadian-clock-controlled endocrine and cytokine signals regulate multipotential innate lymphoid cell progenitors in the bone marrow.

Innate lymphoid cells (ILCs), strategically positioned throughout the body, undergo population declines over time. A solution to counteract this problem is timely mobilization of multipotential progenitors from the bone marrow. It remains unknown what triggers the mobilization of bone marrow ILC progenitors (ILCPs). We report that ILCPs are regulated by the circadian clock to emigrate and generate mature ILCs in the periphery. We found that circadian-clock-defective ILCPs fail to normally emigrate and generate ILCs. We identified circadian-clock-controlled endocrine and cytokine cues that, respectively, regulate the retention and emigration of ILCPs at distinct times of each day. Activation of the stress-hormone-sensing glucocorticoid receptor upregulates CXCR4 on ILCPs for their retention in the bone marrow, while the interleukin-18 (IL-18) and RORα signals upregulate S1PR1 on ILCPs for their mobilization to the periphery. Our findings establish important roles of circadian signals for the homeostatic efflux of bone marrow ILCPs.

Rationale and Design of the mTECH-Rehab Randomized Controlled Trial: Impact of a Mobile Technology Enabled Corrie Cardiac Rehabilitation Program on Functional Status and Cardiovascular Health.

BACKGROUND: Cardiac rehabilitation (CR) is an evidence-based, guideline-recommended intervention for patients recovering from a cardiac event, surgery or procedure that improves morbidity, mortality, and functional status. CR is traditionally provided in-center, which limits access and engagement, most notably among underrepresented racial and ethnic groups due to barriers including cost, scheduling, and transportation access. This study is designed to evaluate the Corrie Hybrid CR, a technology-based, multicomponent health equity-focused intervention as an alternative to traditional in-center CR among patients recovering from a cardiac event, surgery, or procedure compared with usual care alone. METHODS: The mTECH-Rehab (Impact of a Mobile Technology Enabled Corrie CR Program) trial will randomize 200 patients who either have diagnosis of myocardial infarction or who undergo coronary artery bypass grafting surgery, percutaneous coronary intervention, heart valve repair, or replacement presenting to 4 hospitals in a large academic health system in Maryland, United States, to the Corrie Hybrid CR program combined with usual care CR (intervention group) or usual care CR alone (control group) in a parallel arm, randomized controlled trial. The Corrie Hybrid CR program leverages 5 components: (1) a patient-facing mobile application that encourages behavior change, patient empowerment, and engagement with guideline-directed therapy; (2) Food and Drug Administration-approved smart devices that collect health metrics; (3) 2 upfront in-center CR sessions to facilitate personalization, self-efficacy, and evaluation for the safety of home exercise, followed by a combination of in-center and home-based sessions per participant preference; (4) a clinician dashboard to track health data; and (5) weekly virtual coaching sessions delivered over 12 weeks for education, encouragement, and risk factor modification. The primary outcome is the mean difference between the intervention versus control groups in distance walked on the 6-minute walk test (ie, functional capacity) at 12 weeks post randomization. Key secondary and exploratory outcomes include improvement in a composite cardiovascular health metric, CR engagement, quality of life, health factors (including low-density lipoprotein-cholesterol, hemoglobin A1c, weight, diet, smoking cessation, blood pressure), and psychosocial factors. Approval for the study was granted by the local institutional review board. Results of the trial will be published once data collection and analysis have been completed. CONCLUSIONS: The Corrie Hybrid CR program has the potential to improve functional status, cardiovascular health, and CR engagement and advance equity in access to cardiac rehabilitation. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT05238103.

Microbial Metabolite Dysbiosis and Colorectal Cancer.

The global burden of colorectal cancer (CRC) is expected to continuously increase. Through research performed in the past decades, the effects of various environmental factors on CRC development have been well identified. Diet, the gut microbiota and their metabolites are key environmental factors that profoundly affect CRC development. Major microbial metabolites with a relevance for CRC prevention and pathogenesis include dietary fiber-derived short-chain fatty acids, bile acid derivatives, indole metabolites, polyamines, trimethylamine-N-oxide, formate, and hydrogen sulfide. These metabolites regulate various cell types in the intestine, leading to an altered intestinal barrier, immunity, chronic inflammation, and tumorigenesis. The physical, chemical, and metabolic properties of these metabolites along with their distinct functions to trigger host receptors appear to largely determine their effects in regulating CRC development. In this review, we will discuss the current advances in our understanding of the major CRC-regulating microbial metabolites, focusing on their production and interactive effects on immune responses and tumorigenesis in the colon.

Differential Risk of Cancer Associated with Glucagon-like Peptide-1 Receptor Agonists: Analysis of Real-world Databases.

BACKGROUND: Glucagon-like peptide 1 receptor agonists (GLP1Ra) are commonly used in type 2 diabetes mellitus (T2DM). However, differential risk of various cancers among GLP1Ra recipients is unknown. METHODS: We inquired an aggregated electronic health record database, Explorys, and compared the adjusted odds ratio (aOR) of cancers between GLP1Ra and metformin users. Findings were validated in the FDA Adverse Event Reporting System (FDA FAERS). RESULTS: From 1/2005 to 6/2019, we identified 619 340 and 64 230 patients in the metformin and GLP1Ra group, respectively. Within 5 years of starting antidiabetic medications, GLP1Ra was associated with significantly lower incident risk of prostate (aOR 0.81, p = .03), lung (aOR 0.81, p = .05), and colon cancer (aOR 0.85, p = .03), while the risk of thyroid cancer was significantly higher (aOR 1.65, p < .01). Similar findings were seen in the FDA FAERS database, where GLP1Ra was associated with lower risk of prostate (aOR 0.72, p = .08), lung (aOR 0.52, p < .01), colon cancer (aOR 0.82, p = .31), and higher risk of thyroid cancer (aOR 4.33, p < .01). In addition, with longer duration of GLP1Ra use, the risk of prostate, lung, and colon cancer further decreased, suggesting an exposure duration-response relationship. CONCLUSIONS: GLP1Ra is associated with lower risks of prostate, lung, and colon cancer, but higher risk of thyroid cancer.

Incidence and Risk of Various Types of Arterial Thromboembolism in Patients With Cancer.

OBJECTIVE: To describe the temporal association and identify risk factors between cancer diagnosis and various types of arterial thromboembolism (ATE). PATIENTS AND METHODS: We inquired an aggregated electronic health record database (Explorys, IBM Corp., Armonk, New York) and identified patients with cancer from January 1999 to October 2019, with various types of ATE, including myocardial infarction, acute ischemic stroke, acute limb ischemia, acute mesenteric ischemia, acute renal infarction, and retinal artery occlusion. We investigated the temporal relationship between cancer diagnosis and ATE events by examining the incidence ratio (IR) of ATE before and after diagnosis of cancer. RESULTS: We identified 305,384 patients with cancer and ATE. The 30-day interval IR of total ATE was elevated shortly before and after cancer diagnosis, which was consistent among different ATE and cancer types. The incidence was highest within a 330-day window (90 days before and 240 days after cancer diagnosis), and IR peaked at 13.9 (95% confidence interval [CI], 13.6 to 14.2) in the first 30 days following diagnosis of cancer. Compared with patients with cancer who never developed ATE, patients with ATE had more cardiovascular risk factors at baseline. Patients with brain cancer, lung cancer, colorectal cancer, and pancreatic cancer had the highest risk of developing ATE, whereas ATE type was anatomically associated with cancer type. CONCLUSION: In this observational study of an aggregated US patient population, those with newly diagnosed cancer had increased risk of ATE events. This risk was most elevated in a 330-day window around cancer diagnosis and was consistent across different types of ATE and cancer.

IL-4-BATF signaling directly modulates IL-9 producing mucosal mast cell (MMC9) function in experimental food allergy.

BACKGROUND: This study group has previously identified IL-9-producing mucosal mast cell (MMC9) as the primary source of IL-9 to drive intestinal mastocytosis and experimental IgE-mediated food allergy. However, the molecular mechanisms that regulate the expansion of MMC9s remain unknown. OBJECTIVES: This study hypothesized that IL-4 regulates MMC9 development and MMC9-dependent experimental IgE-mediated food allergy. METHODS: An epicutaneous sensitization model was used and bone marrow reconstitution experiments were performed to test the requirement of IL-4 receptor α (IL-4Rα) signaling on MMC9s in experimental IgE-mediated food allergy. Flow cytometric, bulk, and single-cell RNA-sequencing analyses on small intestine (SI) MMC9s were performed to illuminate MMC9 transcriptional signature and the effect of IL-4Rα signaling on MMC9 function. A bone marrow-derived MMC9 culture system was used to define IL-4-BATF signaling in MMC9 development. RESULTS: Epicutaneous sensitization- and bone marrow reconstitution-based models of IgE-mediated food allergy revealed an IL-4 signaling-dependent cell-intrinsic effect on SI MMC9 accumulation and food allergy severity. RNA-sequencing analysis of SI-MMC9s identified 410 gene transcripts reciprocally regulated by IL-4 signaling, including Il9 and Batf. Insilico analyses identified a 3491-gene MMC9 transcriptional signature and identified 2 transcriptionally distinct SI MMC9 populations enriched for metabolic or inflammatory programs. Employing an in vitro MMC9-culture model system showed that generation of MMC9-like cells was induced by IL-4 and this was in part dependent on BATF. CONCLUSIONS: IL-4Rα signaling directly modulates MMC9 function and exacerbation of experimental IgE-mediated food allergic reactions. IL-4Rα regulation of MMC9s is in part BATF-dependent and occurs via modulation of metabolic transcriptional programs.

BATF regulates innate lymphoid cell hematopoiesis and homeostasis.

Early hematopoietic progenitors undergo sophisticated developmental processes to become committed innate lymphoid cell (ILC) progenitors and ultimately mature ILC subsets in the periphery. Basic leucine zipper ATF-like transcription factor (Batf) plays important roles in lymphocyte biology. We report here that Batf regulates the production of bone marrow ILC progenitors and maintenance of peripheral ILCs. The expression of Batf is induced during ILC development at the α-lymphoid progenitor stage in response to the cytokine IL-7. As a potential mechanism, up-regulated Batf binds and activates transcription of the Nfil3 gene to promote ILC hematopoiesis. Batf is necessary to maintain normal numbers of early and late ILC progenitors in the bone marrow and mature ILC1, ILC2, ILC3, and NK cells in most peripheral tissues. Batf deficiency causes ILC lymphopenia, leading to defective ILC responses to inflammatory cytokines and defective immunity to enteric bacterial infections. Thus, Batf plays critical roles in bone marrow hematopoiesis, peripheral homeostasis, and effector functions of ILCs.

Single-Cell Transcriptome Analysis of Colon Cancer Cell Response to 5-Fluorouracil-Induced DNA Damage.

DNA damage often induces heterogeneous cell-fate responses, such as cell-cycle arrest and apoptosis. Through single-cell RNA sequencing (scRNA-seq), we characterize the transcriptome response of cultured colon cancer cell lines to 5-fluorouracil (5FU)-induced DNA damage. After 5FU treatment, a single population of colon cancer cells adopts three distinct transcriptome phenotypes, which correspond to diversified cell-fate responses: apoptosis, cell-cycle checkpoint, and stress resistance. Although some genes are regulated uniformly across all groups of cells, many genes showed group-specific expression patterns mediating DNA damage responses specific to the corresponding cell fate. Some of these observations are reproduced at the protein level by flow cytometry and are replicated in cells treated with other 5FU-unrelated genotoxic drugs, camptothecin and etoposide. This work provides a resource for understanding heterogeneous DNA damage responses involving fractional killing and chemoresistance, which are among the major challenges in current cancer chemotherapy.

RARα supports the development of Langerhans cells and langerin-expressing conventional dendritic cells.

Langerhans cells (LC) are the prototype langerin-expressing dendritic cells (DC) that reside specifically in the epidermis, but langerin-expressing conventional DCs also reside in the dermis and other tissues, yet the factors that regulate their development are unclear. Because retinoic acid receptor alpha (RARα) is highly expressed by LCs, we investigate the functions of RARα and retinoic acid (RA) in regulating the langerin-expressing DCs. Here we show that the development of LCs from embryonic and bone marrow-derived progenitors and langerin+ conventional DCs is profoundly regulated by the RARα-RA axis. During LC differentiation, RARα is required for the expression of a LC-promoting transcription factor Runx3, but suppresses that of LC-inhibiting C/EBPß. RARα promotes the development of LCs and langerin+ conventional DCs only in hypo-RA conditions, a function effectively suppressed at systemic RA levels. Our findings identify positive and negative regulatory mechanisms to tightly regulate the development of the specialized DC populations.

Microbial metabolites, short-chain fatty acids, restrain tissue bacterial load, chronic inflammation, and associated cancer in the colon of mice.

The intestinal immune system is regulated by microbes and their metabolites. The roles of gut microbial metabolites in regulating intestinal inflammation and tumorigenesis are incompletely understood. We systematically studied the roles of short-chain fatty acids (SCFAs) and their receptors (GPR43 or GPR41) in regulating tissue bacterial load, acute versus chronic inflammatory responses, and intestinal cancer development. SCFA receptor-, particularly GPR43-, deficient mice were defective in mounting appropriate acute immune responses to promote barrier immunity, and developed uncontrolled chronic inflammatory responses following epithelial damage. Further, intestinal carcinogenesis was increased in GPR43-deficient mice. Dietary fiber and SCFA administration suppressed intestinal inflammation and cancer in both GPR43-dependent and independent manners. The beneficial effect of GPR43 was not mediated by altered microbiota but by host tissue cells and hematopoietic cells to a lesser degree. We found that inability to suppress commensal bacterial invasion into the colonic tissue is associated with the increased chronic Th17-driven inflammation and carcinogenesis in the intestine of GPR43-deficient mice. In sum, our results reveal the beneficial function of the SCFA-GPR43 axis in suppressing bacterial invasion and associated chronic inflammation and carcinogenesis in the colon.

Regulation of humoral immunity by gut microbial products.

The intestinal tract provides ideal niches for several different microbial species, which are collectively called the gut microbiota. A key host immune effector that controls the microbiota and prevents mucosal infection is IgA. Gut microbiota-derived factors are largely classified into molecular pattern recognition receptor ligands and nutrient-derived metabolites including short-chain fatty acids and adenosine triphosphate. Along with host-derived factors such as retinoic acid, various cytokines and cytokine-like molecules, gut microbial products profoundly shape B cell responses. Gut microbial products can directly regulate B cell activation and differentiation. They can also indirectly affect B cells through epithelial cells, T cells, and myeloid cell subsets. We highlight the various direct and indirect mechanisms by which microbial products regulate humoral immunity.

Prognostic Significance of Hemodynamic and Clinical Stages in the Prediction of Hepatocellular Carcinoma.

BACKGROUND & GOALS: Early identification of hepatocellular carcinoma (HCC) is associated with improved survival for patients with chronic liver disease (CLD). We evaluated the prognostic significance of hemodynamic stage (HS) and clinical stage (CS) in predicting HCC in CLD patients. METHODS: Between January 2006 and May 2014, 801 patients with CLD who underwent hepatic venous pressure gradient (HVPG) measurement were prospectively enrolled. HS was classified by HVPG (mm Hg) as follows: HS-1 (HVPG≤6), HS-2 (612 mm Hg (P=0.033, OR=2.17), CS>2 (P=0.039, OR=2.36), and alpha-fetoprotein (AFP; P=0.017, OR=1.01) were significant predictors of HCC development in all patients. For patients with cirrhosis, ascites aggravation (OR=2.51), HVPG >12 mm Hg (OR=2.46), and CS >2 (OR=2.62) were correlated with HCC development. Areas under receiver operating characteristic curves of the prediction-model, CS, HVPG score, and AFP were 0.797, 0.707, 0.701, and 0.653, respectively. CONCLUSIONS: HCC development correlates with advancing liver fibrosis or disease as measured by HS and CS. In addition, ascites aggravation and elevated AFP appears to be associated with increased incidence of HCC.

Authentic GITR Signaling Fails To Induce Tumor Regression unless Foxp3+ Regulatory T Cells Are Depleted.

The glucocorticoid-induced TNFR family-related protein (GITR, TNFRSF18, CD357) is expressed on effector and regulatory T (Treg) cells. Previous studies demonstrated that GITR triggering by anti-GITR mAb enhanced T and B cell-mediated immune responses. GITR-deficient T cells, however, also proliferate more than normal T cells, and this effect is unexplained. Because the activities of mAbs are controlled by their Fc regions, the true effect of GITR signaling needs to be determined by examining its interaction with authentic ligand. Therefore, we generated a pentamerized form of the GITRL extracellular domain (pGITRL) for ligation to GITR and compared its effect on T cells with that of anti-GITR mAb. The pGITRL was more effective than anti-GITR mAb in enhancing the proliferation of effector and regulatory cells in vitro and in vivo. Nonetheless, the growth of MC38 adenocarcinoma cells in vivo was only suppressed for initial 15 d by pGITRL, whereas it was suppressed indefinitely by anti-GITR mAb. Detailed analysis revealed that pGITRL induced extensive proliferation of Foxp3(+)CD4(+) Treg cells and led to the accumulation of activated Treg cells in tumor tissue and draining lymph nodes. Because GITR signaling could not neutralize the suppressive activity of activated Treg cells, pGITRL seems to lose its adjuvant effect when sufficient activated Treg cells have accumulated in the lymph nodes and tumor tissue. Indeed, the antitumor effects of pGITRL were markedly enhanced by depleting CD4(+) cells. These results suggest that GITR signaling has stimulatory effects on effector T cells and inhibitory effects through Treg cells.

Trends and Disparities in Cardiovascular Mortality Among Survivors of Hodgkin Lymphoma.

BACKGROUND: Over the past decades, survival of patients with Hodgkin lymphoma (HL) has increased but remains curtailed by cardiovascular mortality (CVM). HL survivors at greatest risk for cardiovascular death have not been clearly identified. We sought to report trends of CVM identify HL survivors at highest risk. METHODS: The Surveillance, Epidemiology, and End Results (SEER) database was queried for all adult patients diagnosed with HL (age 20-49 years) between 1990 and 2011. The trend of CVM and disparities are presented. RESULTS: Of 19,781 HL patients, 53% were male and 83% were white; patients had a mean age of 33 ± 8.3 years at diagnosis. Eighteen percent had stage I disease, 45% stage II, 18% stage III, and 15% stage IV. The risk for CVM was higher in blacks (adjusted hazard ratio [HR], 1.97; P = .002), men (adjusted HR, 2.2; P < .001), and patients with older age at diagnosis (adjusted HR, 1.073 per year; P < .001). CVM has decreased, with 5-year cumulative incidence decreasing from 1.17% in 1990 to 0.18% in 2006, averaging 7% per year (adjusted HR, 0.927; P < .001). This trend was seen only in patients with early disease (P < .001) but not with advanced disease (P = NS). CVM as a proportion of all-cause mortality increases sharply at 50 years of age, constituting more than 30% of all causes of death. CONCLUSION: Despite an overall decrease in CVM in HL survivors over the last decades, older patients, black patients, and men, especially those who have advanced-stage disease at diagnosis, are at the highest risk of cardiovascular death. Cardiovascular screening and risk modification should be intensified in HL patients with these characteristics.

Human Tfh and Tfr cells: identification and assessment of their migration potential.

The ability of follicular T cells to migrate into B-cell follicles is central for them to participate in germinal center responses. The chemokine receptor CXCR5 is expressed by both Tfh and Tfr cells and is the defining marker for follicular T cells. In addition, Tfh and Tfr cells express additional chemokine receptors to enable them to interact with B cells and other cell types. CXCR5(+) Tfh and Tfr cells are divided into CCR7(+) perifollicular cells and CCR7(-) follicular cells. Most of the CXCR5(+) CCR7(-) Tfh cells reside in germinal centers and are called GC T cells. The methods to identify human Tfh and Tfr cell subsets based on chemokine receptors and other antigens and assess their migration potential are provided in this article.

A functional relay from progesterone to vitamin D in the immune system.

Progesterone is a steroid hormone that promotes and maintains pregnancy. Vitamin D (vit. D), another steroid hormone, regulates calcium levels and bone health among many of its functions. The two hormones play important roles also in regulating the immune system. Recently, we discovered that the vitamin D receptor (VDR) is induced in T cells by progesterone. This finding connects the function of progesterone to that of vit. D and suggests that the two steroid hormones cooperate with each other for sequential and effective regulation of the immune system. Potential implications of the regulation in health and disease are discussed.

Cutting edge: progesterone directly upregulates vitamin d receptor gene expression for efficient regulation of T cells by calcitriol.

The two nuclear hormone receptor ligands progesterone and vitamin D (vit.D) play important roles in regulating T cells. The mechanism that connects these two hormones in regulating T cells has not been established. In this study, we report that progesterone is a novel inducer of vit.D receptor (VDR) in T cells and makes T cells highly sensitive to calcitriol. At the molecular level, the induction by progesterone is mediated by two progesterone receptor-binding elements in the intron region after the first noncoding exon of the human VDR gene. Increased expression of VDR by progesterone allows highly sensitive regulation of T cells by vit.D even when vit.D levels are suboptimal. This novel regulatory pathway allows enhanced induction of regulatory T cells but suppression of Th1 and Th17 cells by the two nuclear hormones. The results have significant ramifications in effective regulation of T cells to prevent adverse immune responses during pregnancy.