Sepsis remains one of the leading causes of death in burn patients who survive the initial insult of injury. Disruption of the intestinal epithelial barrier has been shown after burn injury; this can ...lead to the translocation of bacteria or their products (e.g., endotoxin) from the intestinal lumen to the circulation, thereby increasing the risk for sepsis in immunocompromised individuals. Since the maintenance of the epithelial barrier is largely dependent on the intestinal microbiota, we examined the diversity of the intestinal microbiome of severely burned patients and a controlled mouse model of burn injury. We show that burn injury induces a dramatic dysbiosis of the intestinal microbiome of both humans and mice and allows for similar overgrowths of Gram-negative aerobic bacteria. Furthermore, we show that the bacteria increasing in abundance have the potential to translocate to extra-intestinal sites. This study provides an insight into how the diversity of the intestinal microbiome changes after burn injury and some of the consequences these gut bacteria can have in the host.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1)-blockade immunotherapies have limited efficacy in the treatment of bladder cancer. Here, we show that NKG2A associates with ...improved survival and responsiveness to PD-L1 blockade immunotherapy in bladder tumors that have high abundance of CD8
T cells. In bladder tumors, NKG2A is acquired on CD8
T cells later than PD-1 as well as other well-established immune checkpoints. NKG2A
PD-1
CD8
T cells diverge from classically defined exhausted T cells through their ability to react to human leukocyte antigen (HLA) class I-deficient tumors using T cell receptor (TCR)-independent innate-like mechanisms. HLA-ABC expression by bladder tumors is progressively diminished as disease progresses, framing the importance of targeting TCR-independent anti-tumor functions. Notably, NKG2A
CD8
T cells are inhibited when HLA-E is expressed by tumors and partly restored upon NKG2A blockade in an HLA-E-dependent manner. Overall, our study provides a framework for subsequent clinical trials combining NKG2A blockade with other T cell-targeted immunotherapies, where tumors express higher levels of HLA-E.
ABSTRACTThe purpose of this investigation was to determine maximal strength and jump performance outcomes of heavy squat training on a low-amplitude (<1.0 mm peak-to-peak) vibration platform (VP). ...Nineteen recreationally resistance-trained college-aged men (22.3 ± 1.66 years) completed the 6-week study. Participants were randomly assigned to one of two training groupsSQT (n = 10) performed conventional back squats on the floor; SQTV (n = 9) performed back squats on the VP. Supervised training took place over 12 sessions (2 days/week) which utilized an aggressive strength development protocol (85-95 % 1-RM), which was identically followed by both groups. After the intervention, both groups showed (via t-test) a marked increase (p < 0.001) in 1-RM squat strength (SQT = 34.5 kg vs SQTV = 36.2 kg), but there was no significant difference (via mixed ANOVA) between groups (p = 0.875). Standing broad jump performance increased by an average of 5-6 cm, but was not significantly changed in either group (SQT; p = 0.199, SQTV; p = 0.087). In conclusion, squats performed with whole body vibration (WBV) were not superior to conventional squats with respect to maximal strength and jump performance outcomes. It appears that there was no additive effect of superimposed WBV training in strength beyond that caused by strength training alone. This study can help strength conditioning professionals and athletes make an informed decision on whether to invest in a VP and use WBV as an alternative or a complementary mode of training.
6-Formylindolo (3, 2-b) Carbazole (FICZ) is a ligand of aryl hydrocarbon receptor (AHR) which regulates Th17 release of IL-17 and IL-22 production. Earlier, we showed that ethanol combined with burn ...injury suppresses Th17 responses and disrupts intestinal barrier leading to increased gut bacterial growth and translocation. Since IL-22 is known for its role in intestinal barrier maintenance, we determined whether treatment of mice with FICZ restores T cell IL-22 release and protects intestine barrier following ethanol and burn injury. Wildtype and Rag1−/− mice were gavaged with ~2.9 g/kg ethanol or water, and given a ~12.5% total body surface area burn. Mice were given FICZ (5 μg) in resuscitation fluid. FICZ treatment of wildtype mice normalized IL-22 and IL-17 in lamina propria and spleen T cells, as well as increased CYP1A1 expression in spleen T cells. This was accompanied by improved gut motility, decreased copy number of small intestine total bacteria and Enterobacteriaceae, attenuation of intestinal tissue levels of IL-6, KC, IL-18, decreased apoptosis, and prevention of gut leakiness following ethanol and burn injury. However, FICZ treatment of Rag1−/− mice did not improve any of the parameters listed after ethanol and burn injury. Additional data generated using mice treated with recombinant IL-22 alone or in combination with anti-IL-18 antibody suggest that full protection of gut barrier integrity requires both IL-18 inhibition and IL-22 restoration following ethanol and burn injury. Together our findings suggest that AHR ligand FICZ may have better therapeutic potential for maintenance of gut barrier function after ethanol and burn injury.
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•Ethanol and burn injury suppresses T cell release of IL-17 and IL-22 and disrupts intestine barrier integrity.•FICZ protects intestine barrier by enhancing T cell release of IL-17 and IL-22 and decreasing IL-18 in small intestine.•FICZ-mediated protection is diminished in Rag1 knockout mice.
ABSTRACTIntestine barrier disruption and bacterial translocation can contribute to sepsis and multiple organ failure, leading causes of mortality in burn-injured patients. In addition, findings ...suggest that ethanol (alcohol) intoxication at the time of injury worsens symptoms associated with burn injury. We have previously shown that interleukin-22 (IL-22) protects from intestinal leakiness and prevents overgrowth of gram-negative bacteria following ethanol and burn injury, but how IL-22 mediates these effects has not been established. Here, utilizing a mouse model of ethanol and burn injury, we show that the combined insult results in a significant loss of proliferating cells within small intestine crypts and increases Enterobacteriaceae copies, despite elevated levels of the antimicrobial peptide lipocalin-2. IL-22 administration restored numbers of proliferating cells within crypts, significantly increased Reg3β, Reg3γ, lipocalin-2 AMP transcript levels in intestine epithelial cells, and resulted in complete reduction of Enterobacteriaceae in the small intestine. Knockout of signal transducer and activator of transcription factor-3 (STAT3) in intestine epithelial cells resulted in complete loss of IL-22 protection, demonstrating that STAT3 is required for intestine barrier protection following ethanol combined with injury. Together, these findings suggest that IL-22/STAT3 signaling is critical to gut barrier integrity and targeting this pathway may be of beneficial clinical relevance following burn injury.
Over 1.4 million Americans have been diagnosed with inflammatory bowel disease (IBD), and ulcerative colitis (UC) makes up approximately half of those diagnoses. As a disease, UC cycles between ...periods of remission and flare, which is characterized by intense abdominal pain, increased weight loss, intestinal inflammation, rectal bleeding, and dehydration. Interestingly, a widespread recommendation to IBD patients for avoidance of a flare period is “Don't Drink Alcohol” as recent work correlated alcohol consumption with increased GI symptoms in patients with IBD. Alcohol alone not only induces a systemic pro‐inflammatory response, but can also be directly harmful to gut barrier integrity. However, how alcohol could result in the exacerbation of UC in both patients and murine models of colitis has yet to be elucidated. Therefore, we conducted a retrospective analysis of patients admitted for IBD with a documented history of alcohol use in conjunction with a newly developed mouse model of binge alcohol consumption following dextran sulfate sodium (DSS)‐induced colitis. We found that alcohol negatively impacts clinical outcomes of patients with IBD, specifically increased intestinal infections, antibiotic injections, abdomen CT scans, and large intestine biopsies. Furthermore, in our mouse model of binge alcohol consumption following an induced colitis flare, we found alcohol exacerbates weight loss, clinical scores, colonic shortening and inflammation, and propensity to infection. These findings highlight alcohol's ability to potentiate symptoms and susceptibility to infection in UC and suggest alcohol as an underlying factor in perpetuating symptoms of IBD.
This study builds on previous findings that alcohol has adverse effects in IBD and establishes these effects in a mouse model of colitis.
IL‐6 and TGF‐β do not appear to influence IL‐23‐mediated restoration of Th17 effector cytokines after ethanol and burn injury.
T cells play a critical role in host defense against intestinal ...bacteria. We have shown that ethanol combined with burn injury suppresses Peyer's patch (PP) Th17 cytokines 1 d after injury. We assessed the mechanism of suppressed Th17 effector functions. Mice were gavaged with ethanol 4 h before burn injury and euthanized 1, 3, and 7 d after injury. Mesenteric lymph nodes (MLNs), PPs, and spleen Th1 and Th17 cytokines were assessed. A significant decrease in IL‐17, IL‐22, IL‐2, and IFN‐γ were observed in all 3 lymphoid organs 1 and 3 d after injury. We used splenic cells to study the role of IL‐6, IL‐23, TGF‐β, and aryl hydrocarbon receptor (AHR) in suppressing Th17 cytokines. We also assessed whether the AHR agonist 6‐formylindolo (3, 2‐b) carbazole (FICZ) modulates Th17 cytokines. We found a significant decrease in IL‐6 and TGF‐β after ethanol and burn; IL‐23 was undetectable. The reconstitution of IL‐23 in culture medium increased IL‐17 by 2‐fold and IL‐22 by 20‐fold in cells from burn ethanol mice. The restoration of IL‐6 and TGF‐β combined did not influence the release of Th17 cytokines. We observed that AHR was necessary for IL‐23 restoration of IL‐22 after ethanol and burn injury. The AHR agonist FICZ enhanced IL‐22, but not IL‐17. None of these treatments influenced the release of Th1 cytokines. Together, these results suggest that IL‐23 plays a critical role in regulation of Th17 cytokines. Furthermore, IL‐6 and TGF‐β do not appear to influence IL‐23‐mediated restoration of Th17 cytokines after ethanol and burn injury.
Ethanol exposure at the time of burn injury is a major contributor to post-burn pathogenesis. Many of the adverse effects associated with ethanol and burn injury are linked to an impaired intestinal ...barrier. The combined insult causes intestinal inflammation, resulting in tissue damage, altered tight junction expression, and increased intestinal permeability. MicroRNAs play a critical role in maintaining intestinal homeostasis including intestinal inflammation and barrier function. Specifically, miR-150 regulates inflammatory mediators which can contribute to gut barrier disruption. The present study examined whether ethanol and burn injury alter expression of microRNA processing enzymes (Drosha, Dicer, and Argonaute-2) and miR-150 in the small intestine. Male mice were gavaged with ethanol (~2.9g/kg) 4h prior to receiving a ~12.5% total body surface area full thickness burn. One or three days after injury, mice were euthanized and small intestinal epithelial cells (IECs) were isolated and analyzed for expression of microRNA biogenesis components and miR-150. Dicer mRNA and protein levels were not changed following the combined insult. Drosha and Argonaute-2 mRNA and protein levels were significantly reduced in IECs one day after injury; which accompanied reduced miR-150 expression. To further determine the role of miR-150 in intestinal inflammation, young adult mouse colonocytes were transfected with a miR-150 plasmid and stimulated with LPS (100ng/ml). miR-150 overexpression significantly reduced IL-6 and KC protein levels compared to vector control cells challenged with LPS. These results suggest that altered microRNA biogenesis and associated decrease in miR-150 likely contribute to increased intestinal inflammation following ethanol and burn injury.
•Ethanol and burn injury decreases microRNA biogenesis components Drosha and Argonaute-2 in small intestine.•Ethanol and burn injury results in diminished expression of miR-150 in the small intestine.•Overexpression of miR-150 in YAMCs suppresses IL-6 and KC suggesting that miR-150 may have a role in inflammation following ethanol and burn injury.
ABSTRACTTraumatic injury remains one of the most prevalent reasons for patients to be hospitalized. Burn injury accounts for 40,000 hospitalizations in the United States annually, resulting in a ...large burden on both the health and economic system and costing millions of dollars every year. The complications associated with postburn care can quickly cause life-threatening conditions including sepsis and multiple organ dysfunction and failure. In addition, alcohol intoxication at the time of burn injury has been shown to exacerbate these problems. One of the biggest reasons for the onset of these complications is the global suppression of the host immune system and increased susceptibility to infection. It has been hypothesized that infections after burn and other traumatic injury may stem from pathogenic bacteria from within the host’s gastrointestinal tract. The intestine is the major reservoir of bacteria within the host, and many studies have demonstrated perturbations of the intestinal barrier after burn injury. This article reviews the findings of these studies as they pertain to changes in the intestinal immune system after alcohol and burn injury.
ABSTRACTAlcohol intoxication at the time of burn injury exacerbates postburn pathogenesis. Recent findings suggest gut barrier integrity is compromised after combined alcohol and burn insult, which ...could contribute to these complications. Tight junction proteins and mucins play critical roles in keeping the gut barrier intact. Therefore, the goal of this study was to examine the effects of alcohol and burn injury on claudin and mucin expression in the intestines. We also evaluated if the combined insult differentially influences their expression in the small and large intestines. Male C57BL/6 mice were given a single dose of 2.9 g/kg ethanol before an approximately 12.5% body area burn. One and three days after injury, we profiled expression of several tight junction proteins, mucin, and bacterial 16S rRNA genes in the small and large intestines, using qPCR. We observed >50% decrease in claudin-4 and claudin-8 genes in both ileal and colonic epithelial cells 1 day after injury. Claudin-2 was significantly upregulated, and occludin was downregulated in the small intestine 1 day after injury. Mucin-3 expression was substantially elevated (>50%) in the small intestine, whereas mucin-2 and mucin-4 were considerably diminished in the colon (>50%) 1 day after injury. Most of the parameters were normalized to sham levels on day 3, except for mucin-3 and claudin-8, which remained decreased in the large intestine. Neither alcohol nor burn alone resulted in changes in junction or mucin gene expression compared to shams. This was accompanied with increases in the family of Gram-negative bacteria, Enterobacteriaceae, in both the small and the large intestines 1 day after injury. These findings suggest that alcohol and burn injury disrupts the normal gut microbiota and alters tight junction and mucin expression in the small and large intestines.
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