Epithelial Nlrp10 inflammasome mediates protection against intestinal autoinflammation.

Unlike other nucleotide oligomerization domain-like receptors, Nlrp10 lacks a canonical leucine-rich repeat domain, suggesting that it is incapable of signal sensing and inflammasome formation. Here we show that mouse Nlrp10 is expressed in distal colonic intestinal epithelial cells (IECs) and modulated by the intestinal microbiome. In vitro, Nlrp10 forms an Apoptosis-associated speck-like protein containing a caspase-recruitment domain (ASC)-dependent, m-3M3FBS-activated, polyinosinic:polycytidylic acid-modulated inflammasome driving interleukin-1ß and interleukin-18 secretion. In vivo, Nlrp10 signaling is dispensable during steady state but becomes functional during autoinflammation in antagonizing mucosal damage. Importantly, whole-body or conditional IEC Nlrp10 depletion leads to reduced IEC caspase-1 activation, coupled with enhanced susceptibility to dextran sodium sulfate-induced colitis, mediated by altered inflammatory and healing programs. Collectively, understanding Nlrp10 inflammasome-dependent and independent activity, regulation and possible human relevance might facilitate the development of new innate immune anti-inflammatory interventions.

Regulatory T cell-derived interleukin-15 promotes the diversity of immunological memory.

While the immunosuppressive function of regulatory T (Treg) cells has been extensively studied, their immune-supportive roles have been less well investigated. Using a lymphocytic choriomeningitis virus (LCMV) Armstrong infection mouse model, we found that Treg cell-derived interleukin (IL)-15 is required for long-term maintenance of the KLRG1+ IL-7Rα- CD62L- terminal effector memory CD8+ T (tTEM) cell subset, but dispensable for the suppressive function of Treg cells themselves. In contrast, deletion of Il15 from other sources, including myeloid cells and muscles, did not affect the composition of the memory CD8+ T cell pool. Our findings identify Treg cells as an essential IL-15 source maintaining tTEM cells and suggest that Treg cells promote the diversity of immunological memory.

Rgs16 promotes antitumor CD8+ T cell exhaustion.

T cells become functionally exhausted in tumors, limiting T cell-based immunotherapies. Although several transcription factors regulating the exhausted T (Tex) cell differentiation are known, comparatively little is known about the regulators of Tex cell survival. Here, we reported that the regulator of G protein signaling 16 (Rgs-16) suppressed Tex cell survival in tumors. By performing lineage tracing using reporter mice in which mCherry marked Rgs16-expressing cells, we identified that Rgs16+CD8+ tumor-infiltrating lymphocytes (TILs) were terminally differentiated, expressed low levels of T cell factor 1 (Tcf1), and underwent apoptosis as early as 6 days after the onset of Rgs16 expression. Rgs16 deficiency inhibited CD8+ T cell apoptosis and promoted antitumor effector functions of CD8+ T cells. Furthermore, Rgs16 deficiency synergized with programmed cell death protein 1 (PD-1) blockade to enhance antitumor CD8+ T cell responses. Proteomics revealed that Rgs16 interacted with the scaffold protein IQGAP1, suppressed the recruitment of Ras and B-Raf, and inhibited Erk1 activation. Rgs16 deficiency enhanced antitumor CD8+ TIL survival in an Erk1-dependent manner. Loss of function of Erk1 decreased antitumor functions of Rgs16-deficient CD8+ T cells. RGS16 mRNA expression levels in CD8+ TILs of patients with melanoma negatively correlated with genes associated with T cell stemness, such as SELL, TCF7, and IL7R, and predicted low responses to PD-1 blockade. This study uncovers Rgs16 as an inhibitor of Tex cell survival in tumors and has implications for improving T cell-based immunotherapies.

Decannulation and Functional Outcome After Tracheostomy in Patients with Severe Stroke (DECAST): A Prospective Observational Study.

BACKGROUND: Tracheostomy is performed in ventilated stroke patients affected by persisting severe dysphagia, reduced level of consciousness, or prolonged mechanical ventilation. The study aim was to determine the frequency and predictors of successful decannulation and long-term functional outcome in tracheotomized stroke patients. METHODS: A prospective single-center observational study recruited ventilated patients with ischemic stroke, intracerebral hemorrhage, and subarachnoid hemorrhage. Follow-up visits were performed at hospital discharge, 3, and 12 months. Competing risk analyses were performed to identify predictors of decannulation. RESULTS: We included 53 ventilated stroke patients who had tracheostomy. One year after tracheostomy, 19 patients were decannulated (median [IQR] time to decannulation 74 [58-117] days), 13 patients were permanently cannulated, and 21 patients died without prior removal of the cannula. Independent predictors for decannulation in our cohort were patient age (HR 0.95 [95% CI: 0.92-0.99] per one year increase, p = 0.003) and absence of sepsis (HR 4.44 [95% CI: 1.33-14.80], p = 0.008). Compared to surviving patients without cannula removal, decannulated patients had an improved functional outcome after one year (median modified Rankin Scale score 4 vs. 5 [p < 0.001]; median Barthel index 35 vs. 5 [p < 0.001]). CONCLUSIONS: Decannulation was achieved in 59.4% of stroke patients surviving the first 12 months after tracheostomy and was associated with better functional outcome compared to patients without decannulation. Further prospective studies with larger sample sizes are needed to confirm our results.