Background: Intestinal barrier defect is an essential inflammatory bowel disease (IBD) pathogenesis. Mitochondrial dysfunction results in energy deficiency and oxidative stress, which contribute to the pathogenesis of IBD. β-arrestin1 (ARRB1) is a negative regulator that promotes G protein-coupled receptors desensitization, endocytosis, and degradation. However, its role in maintaining the intestinal barrier remains unclear.
Methods: Dextran sulfate sodium-induced colitis was performed in ARRB1 knockout and wild-type mice. Intestinal permeability and tight junction proteins were measured to evaluate the intestinal barrier. Mitochondria function and mitophagic flux in mice and cell lines were detected. Finally, the interaction between ARRB1 and mitofusin 2 was investigated by co-immunoprecipitation and dual luciferase assay.
Results: We identified that ARRB1 protected the intestinal tight junction barrier against experimental colitis in vivo. ARRB1 deficiency was accompanied by abnormal mitochondrial morphology, lower adenosine triphosphate (ATP) production, and severe oxidative stress. In vitro, the knockdown of ARRB1 reduced ATP levels and mitochondrial membrane potential while increasing reactive oxygen species levels and oxidative stress. Upon ARRB1 ablation, mitophagy was inhibited, accompanied by decreased LC3BII, phosphatase and tension homologue-induced protein kinase1 (PINK1), and parkin, but increased p62 expression. Mitophagy inhibition via PINK1 siRNA or mitochondrial division inhibitor 1 impaired ARRB1-mediated tight junction protection. The interaction of ARRB1 with E2F1 activated mitophagy by enhancing the transcription of mitofusin 2.
Conclusions: Our results suggest that ARRB1 is critical to maintaining the intestinal tight junction barrier by promoting mitophagy. These results reveal a novel link between ARRB1 and the intestinal tight junction barrier, which provides theoretical support for colitis treatment.
Microorganisms play an important role in the pathogenesis of inflammatory bowel disease (IBD). The oral cavity, the second-largest microbial niche, is connected to the gastro-intestinal tract. Ectopic gut colonization by oral microbes is a signature of IBD. Current studies suggest that patients with IBD often report more oral manifestations and these oral issues are closely linked with disease activity. Murine studies have indicated that several oral microbes exacerbate intestinal inflammation. Moreover, intestinal inflammation can promote oral microbial dysbiosis and the migration of oral microbes to the gastro-intestinal tract. The reciprocal consequences of oral microbial dysbiosis and IBD, specifically through metabolic alterations, have not yet been elucidated. In this review, we summarize the relationship between oral bacteria and IBD from multiple perspectives, including clinical manifestations, microbial dysbiosis, and metabolic alterations, and find that oral pathogens increase anti-inflammatory metabolites and decrease inflammation-related metabolites.
Chronic liver disease (CLD) is a significant contributor to global mortality. For people who are living with CLD, however, there is a substantial and often overlooked burden of physical and psychological symptoms that significantly affect health-related quality of life. CLD frequently presents with a multitude of interrelated and intricate symptoms, including fatigue, pruritus, muscle cramps, sexual dysfunction, and falls. Increasingly, there is interest in studying and developing interventional strategies to provide a more global approach to managing these complex patients. Moreover, in addition to established guidelines for the management of conventional complications, such as ascites and hepatic encephalopathy, there have been efforts in developing evidence-based guidance for the treatment of the more subjective yet still problematic elements. This review will address the management of these less "classical" but nonetheless important symptoms.
Cirrhosis with complications of liver decompensation and hepatocellular carcinoma (HCC) constitute a leading cause of morbidity and mortality worldwide. Portal hypertension is central to the progression of liver disease and decompensation. The most recent Baveno VII guidance included revision of the nomenclature for chronic liver disease, termed compensated advanced chronic liver disease, and leveraged the use of liver stiffness measurement to categorize the degree of portal hypertension. Additionally, non-selective beta blockers, especially carvedilol, can improve portal hypertension and may even have a survival benefit. Procedural techniques with interventional radiology have become more advanced in the management of refractory ascites and variceal bleeding, leading to improved prognosis in patients with decompensated liver disease. While lactulose and rifaximin are the preferred treatments for hepatic encephalopathy, many alternative treatment options may be used in refractory cases and even procedural interventions such as shunt embolization may be of benefit. The approval of terlipressin for the treatment of hepatorenal syndrome (HRS) in the USA has improved the way in which HRS is managed and will be discussed in detail. Malnutrition, frailty, and sarcopenia lead to poorer outcomes in patients with decompensated liver disease and should be addressed in this patient population. Palliative care interventions can lead to improved quality of life and clinical outcomes. Lastly, the investigation of systemic therapies, in particular immunotherapy, has revolutionized the management of HCC. These topics will be discussed in detail in this review.