PPARγ: The Central Mucus Barrier Coordinator in Ulcerative Colitis

Author(s):  
Jian Fang ◽  
Hui Wang ◽  
Zhe Xue ◽  
Yinyin Cheng ◽  
Xiaohong Zhang

Abstract Ulcerative colitis (UC) is an idiopathic, long-term inflammatory disorder of the colon, characterized by a continuous remitting and relapsing course. The intestinal mucus barrier is the first line at the interface between the host and microbiota and acts to protect intestinal epithelial cells from invasion. Data from patients and animal studies have shown that an impaired mucus barrier is closely related to the severity of UC. Depletion of the mucus barrier is not just the strongest but is also the only independent risk factor predicting relapse in patients with UC. Peroxisome proliferator-activated receptor gamma (PPARγ), a nuclear transcription regulator, is involved in the regulation of inflammatory cytokine expression. It is also known to promote mucus secretion under pathological conditions to expel pathogenic bacteria or toxins. More important, PPARγ has been shown to affect host-microbiota interactions by modulating the energy metabolism of colonocytes and the oxygen availability of the intestinal microbiome. It is well known that gut microbiota homeostasis is essential for butyrate generation by the commensal bacteria to supply energy resources for colonocytes. Therefore, it can be speculated that PPARγ, as a central coordinator of the mucus barrier, may be a promising target for the development of effective agents to combat UC.

Author(s):  
Yuvaraj S ◽  
B R Prashantha Kumar

: Peroxisome proliferator activated receptors (PPARs) are group of nuclear receptors and the ligand-activated intracellular transcription factors that are known to play a key role in physiological processes such as cell metabolism, proliferation, differentiation, tissue remodeling, inflammation, and atherosclerosis. However, in the past two decades, many reports claim that PPARs also play an imperious role as a tumor suppressor. PPAR- gamma (PPARγ), one of the best-known from the family of PPARs, is known to express in colon, breast, bladder, lung, and prostate cancer cells. Its function in tumour cells includes the modulation of several pathways involved in multiplication and apoptosis. The ligands of PPARγ act by PPARγ dependent as well as independent pathways and are also found to regulate different inflammatory mediators and transcription factors in systemic inflammation and in tumor microenvironment. Both synthetic and natural ligands that are known to activate PPARγ, suppress the tumor cell growth and multiplication through the regulation of inflammatory pathways, as found out from different functional assays and animal studies. Cancer and inflammation are interconnected process that are now being targeted to achieve tumor suppression by decreasing the risks and burden posed by cancer cells. Therefore, PPARγ can serve as a promising target for development of clinical drug molecule attenuating the proliferation of cancer cells. In this perspective, this mini review highlights the PPARγ as a potential target for drug development aiming for anti-inflammatory and thereby suppressing tumors.


2021 ◽  
Vol 22 (2) ◽  
pp. 934
Author(s):  
Woon-Man Kung ◽  
Muh-Shi Lin

Proinflammatory response and mitochondrial dysfunction are related to the pathogenesis of neurodegenerative diseases (NDs). Nuclear factor κB (NFκB) activation has been shown to exaggerate proinflammation and mitochondrial dysfunction, which underlies NDs. CDGSH iron-sulfur domain 2 (CISD2) has been shown to be associated with peroxisome proliferator-activated receptor-β (PPAR-β) to compete for NFκB and antagonize the two aforementioned NFκB-provoked pathogeneses. Therefore, CISD2-based strategies hold promise in the treatment of NDs. CISD2 protein belongs to the human NEET protein family and is encoded by the CISD2 gene (located at 4q24 in humans). In CISD2, the [2Fe-2S] cluster, through coordinates of 3-cysteine-1-histidine on the CDGSH domain, acts as a homeostasis regulator under environmental stress through the transfer of electrons or iron-sulfur clusters. Here, we have summarized the features of CISD2 in genetics and clinics, briefly outlined the role of CISD2 as a key physiological regulator, and presented modalities to increase CISD2 activity, including biomedical engineering or pharmacological management. Strategies to increase CISD2 activity can be beneficial for the prevention of inflammation and mitochondrial dysfunction, and thus, they can be applied in the management of NDs.


Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Noriyuki Naya ◽  
Keita Fukao ◽  
Akemi Nakamura ◽  
Kohji Nomura ◽  
Seijiro Hara ◽  
...  

PPARδ is one of the transcription factors that regulate lipid metabolism. Recently, PPARδ agonists have been reported to induce the elevation of plasma HDL-C levels in obese mice, rhesus monkeys as well as humans, indicating their potentials as a new class of HDL-C raising agent. In addition, anti-atherosclerotic effects of PPARδ agonists were reported in LDLR-KO and ApoE-KO mice. In these mice, however, the lipoprotein profiles are greatly different from those in humans in terms of the deficiency in CETP and ApoB100, and thus the anti-inflammatory effects were regarded as a main anti-atherosclerotic mechanism of PPARδ agonists. It has been reported that human ApoB100/CETP transgenic (hApoB100/CETP-Tg) mice have similar lipoprotein profiles with humans. In this study, we used hApoB100/CETP-Tg mice placed under a western diet for evaluation of GW501516, one of the most potent and selective PPARδ agonists, in order to investigate the linkage between HDL-C elevation and anti-atherosclerotic potency. For evaluation of plasma HDL-C levels, the hApoB100/CETP-Tg mice were orally treated with GW501516 for 1 week and its potency was compared with fenofibrate, a PPARα agonist used in the clinic. For evaluation of the anti-atherosclerotic effect, the mice were orally treated with GW501516 for 18 weeks and atherosclerosis at the aortic valves was determined by cross-sectional lesion analysis. Serum lipoprotein parameters were periodically monitored and lipoprotein profiles were analyzed by FPLC method. Treatment with GW501516 resulted in significant elevation of plasma HDL-C levels with more potency compared to fenofibrate (24% and 15% elevation at 10mg/kg, respectively). Serum apoA-I was also increased by the similar ratio as HDL-C, and the particle size of HDL was not changed, suggesting that the numbers of HDL particle are increased by GW501516. Long term treatment of GW501516 (3 and 10 mg/kg) resulted in dose-dependent suppression of atherosclerosis (42 and 57% inhibition, respectively) with a strong correlation with HDL-C elevation (p<0.001). By using hApoB100/CETP-Tg mice, PPARδ was confirmed as a promising target of anti-atherosclerotic therapy as a new class of HDL-C raising agent.


2021 ◽  
Vol 12 ◽  
Author(s):  
Shanshan Guo ◽  
Wenye Geng ◽  
Shan Chen ◽  
Li Wang ◽  
Xuli Rong ◽  
...  

The effects of ginger on gastrointestinal disorders such as ulcerative colitis have been widely investigated using experimental models; however, the mechanisms underlying its therapeutic actions are still unknown. In this study, we investigated the correlation between the therapeutic effects of ginger and the regulation of the gut microbiota. We used dextran sulfate sodium (DSS) to induce colitis and found that ginger alleviated colitis-associated pathological changes and decreased the mRNA expression levels of interleukin-6 and inducible nitric oxide synthase in mice. 16s rRNA sequencing analysis of the feces samples showed that mice with colitis had an intestinal flora imbalance with lower species diversity and richness. At the phylum level, a higher abundance of pathogenic bacteria, Proteobacteria and firmicutes, were observed; at the genus level, most samples in the model group showed an increase in Lachnospiraceae_NK4A136_group. The overall analysis illustrated an increase in the relative abundance of Lactobacillus_murinus, Lachnospiraceae_bacterium_615, and Ruminiclostridium_sp._KB18. These increased pathogenic bacteria in model mice were decreased when treated with ginger. DSS-treated mice showed a lower abundance of Muribaculaceae, and ginger corrected this disorder. The bacterial community structure of the ginger group analyzed with Alpha and Beta indices was similar to that of the control group. The results also illustrated that altered intestinal microbiomes affected physiological functions and adjusted key metabolic pathways in mice. In conclusion, this research presented that ginger reduced DSS-induced colitis severity and positively regulated the intestinal microbiome. Based on the series of data in this study, we hypothesize that ginger can improve diseases by restoring the diversity and functions of the gut microbiota.


Cells ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 2234 ◽  
Author(s):  
Joseph M. Chambers ◽  
Rebecca A. Wingert

Peroxisome proliferator-activated receptor gamma co-activator 1 alpha (PGC-1α) is perhaps best known as a master regulator of mitochondrial biogenesis and function. However, by virtue of its interactions as a coactivator for numerous nuclear receptors and transcription factors, PGC-1α also regulates many tissue-specific tasks that include adipogenesis, angiogenesis, gluconeogenesis, heme biosynthesis, thermogenesis, and cellular protection against degeneration. Knowledge about these functions continue to be discovered with ongoing research. Unsurprisingly, alterations in PGC-1α expression lead to a range of deleterious outcomes. In this review, we provide a brief background on the PGC-1 family with an overview of PGC-1α’s roles as an adaptive link to meet cellular needs and its pathological consequences in several organ contexts. Among the latter, kidney health is especially reliant on PGC-1α. Thus, we discuss here at length how changes in PGC-1α function impact the states of renal cancer, acute kidney injury (AKI) and chronic kidney disease (CKD), as well as emerging data that illuminate pivotal roles for PGC-1α during renal development. We survey a new intriguing association of PGC-1α function with ciliogenesis and polycystic kidney disease (PKD), where recent animal studies revealed that embryonic renal cyst formation can occur in the context of PGC-1α deficiency. Finally, we explore future prospects for PGC-1α research and therapeutic implications for this multifaceted coactivator.


2021 ◽  
Vol 12 ◽  
Author(s):  
Shuting Wen ◽  
Long He ◽  
Zhuotai Zhong ◽  
Runyuan Zhao ◽  
Senhui Weng ◽  
...  

Inflammatory bowel disease (IBD) is a chronic inflammatory disorder with gut microbiota disequilibrium and regulatory T (Treg)/T helper 17 (Th17) immune imbalance. Stigmasterol, a plant-derived sterol, has shown anti-inflammatory effects. Our study aimed to identify the effects of stigmasterol on experimental colitis and the related mechanisms. Stigmasterol treatment restored the Treg/Th17 balance and altered the gut microbiota in a dextran sodium sulfate (DSS)-induced colitis model. Transplantation of the faecal microbiota of stigmasterol-treated mice significantly alleviated inflammation. Additionally, stigmasterol treatment enhanced the production of gut microbiota-derived short-chain fatty acids (SCFAs), particularly butyrate. Next, human naïve CD4+ T cells sorted from IBD patients were cultured under Treg- or Th17-polarizing conditions; butyrate supplementation increased the differentiation of Tregs and decreased Th17 cell differentiation. Mechanistically, butyrate activated peroxisome proliferator-activated receptor gamma (PPARγ) and reprogrammed energy metabolism, thereby promoting Treg differentiation and inhibiting Th17 differentiation. Our results demonstrate that butyrate-mediated PPARγ activation restores the balance of Treg/Th17 cells, and this may be a possible mechanism, by which stigmasterol attenuates IBD.


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