Psyllium seed husk regulates the gut microbiota and improves mucosal barrier injury in the colon to attenuate renal injury in 5/6 nephrectomy rats.

Chronic kidney disease (CKD) can cause gut microbiota dysbiosis and thus impair intestinal barrier function. Disruption of intestinal homeostasis facilitates the production of enterogenic toxins, which exacerbate CKD-induced uremic toxicity and inflammation. Dietary fiber, by targeting the gut-kidney axis, could be used for CKD treatment. Psyllium seed husk (PSH) extracted from the seeds of Plantago ovata contains highly branched, gel-forming arabinoxylan. Positive effects of PSH on host physiology have been demonstrated but whether it also acts on the microbial ecosystem in CKD patients is unknown. In this study, the effects of dietary PSH on the gut microbiota, intestinal barrier function, systemic inflammation, uremic toxins, and renal injury were investigated in 5/6 nephrectomy (5/6Nx) CKD rats. Blood, feces, and kidney and colon tissues were collected from PSH-treated and control rats and subjected to biochemical and histological analyses, enzyme-linked immunosorbent assays, and 16SrRNA sequencing. PSH supplementation reduced serum creatinine and blood urea nitrogen levels, and attenuated renal tubular interstitial injury, in 5/6Nx rats. 16SrRNA sequencing showed that PSH improved the gut microbiota and intestinal barrier function in addition to down-regulating serum interleukin (IL)-1, IL-6, and indoxyl sulfate levels. Together, these results demonstrate the potential of PSH supplementation for treating CKD, including by improving intestinal microecology, reducing uremic toxin levels and systemic inflammation, and delaying disease progression.

Tryptophan intake, not always the more the better.

Objectives: To investigate the effects of excessive tryptophan intake on the body and the effects of tryptophan metabolism-related aryl hydrocarbon receptor (AhR) pathway in healthy rats and chronic kidney disease rats, to study the adverse effects of excess tryptophan. Design: In Part I Experiment, the healthy rats were fed with diet containing 0.6, 1.2 and 1.8% tryptophan for 12 weeks. After the intervention, the blood and kidney tissues were collected. Serum creatinine and blood urea nitrogen were detected. Hematoxylin-eosin (H&E) staining was used to observe renal pathological changes. Enzyme-linked immunosorbent assay was used to detect serum kynurenic acid and AhR levels. The kidney levels of AhR, CyP1A1 and CyP1B1 were detected by western-blot. In Part II Experiment, the chronic kidney disease (CKD) model was induced by intra-gastric gavage with adenine for 4 weeks. Then the CKD rats were given tryptophan at a dose of 100 mg/kg or 500 mg/kg for eight weeks. Rat survival curve, renal function, renal tissue pathology and serum AhR were detected. Tryptophan-targeted ultra-high-performance liquid chromatography coupled with multiple reaction monitoring mass spectrometry (UHPLC-MRM-MS) was employed to quantitatively access the tryptophan-targeted metabolites in two parts experiments. Results: In part I experiment, high tryptophan diet can increase the level of blood urea nitrogen (BUN) in healthy rats and induce focal renal tubulointerstitial injury. Tryptophan-targeted analyzes showed that high tryptophan diet feeding can significantly increase the concentration of kynurenine and indole metabolites. The serum AhR level and kidney AhR, CyP1A1 and CyP1B1 were also significantly increased in high tryptophan diet rats. In part II experiment, high tryptophan intervention induced a significant increase in mortality, serum creatinine, urea nitrogen levels, and renal pathological damage in CKD rats. The levels of tryptophan-targeted metabolites, kynurenine, xanthurenate, picolinic acid, 5-hydroxyindole-3-acetic acid, indole-3-lactic acid, indoleacetate and indoxyl sulfate, showed an upward trend in the high-dose tryptophan group (Ade + Trp-H) compared with the adenine group. The serum AhR of Ade + Trp-H rats was significantly higher than those of adenine rats. Conclusion: Moderate tryptophan intake may be beneficial, but excessive tryptophan can lead to accumulation of kynurenine and indole metabolites, activate AhR pathway and induce kidney injury.

Astragaloside IV attenuates indoxyl sulfate-induced injury of renal tubular epithelial cells by inhibiting the aryl hydrocarbon receptor pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Astragalus membranaceus Fisch. ex Bunge has long been used to treat chronic kidney disease (CKD) in China. However, the mechanism of action requires further study. Indoxyl sulfate accumulation is the key cause of CKD progression. The aryl hydrocarbon receptor (AhR) plays an essential role in the renal tubular injury induced by indoxyl sulfate (IS). AIM: We explored the effects of Astragaloside IV (AS-IV), a minor component of the flowering perennial Astragalus membranaceus Fisch. ex Bunge, on AhR activity during IS-induced injury of renal tubular epithelial cells. METHODS: C57BL/6 mice fed a 0.2% adenine diet (adenine + IS) and intraperitoneally injected with IS were used to study the protective effects of AS-IV, and specifically the effect on the AhR. In addition, apoptosis (annexin/PI), oxidative stress and the AhR pathway were investigated in IS-stimulated HK-2 cells treated with AS-IV. The binding of AS-IV to the AhR was assessed in a molecular docking analysis. AhR knockdown using AhR siRNA allowed determination of the effects of AS-IV in IS-stimulated HK-2 cells. RESULTS: AS-IV inhibited tubulointerstitial injury in adenine + IS mice. While AS-IV did not reduce serum IS levels, it did inhibit AhR expression in the kidney. In IS-stimulated HK-2 cells, AS-IV also dramatically reduced apoptosis, decreased oxidative stress responses and inhibited the expression of the AhR pathway. The molecular docking analysis showed surface binding of AS-IV to the AhR. Following AhR knockdown in HK-2 cells, IS-induced apoptosis was reduced and could not be further reduced by AS-IV. CONCLUSION: By targeting the AhR, AS-IV may alleviate IS-induced renal tubular injury, thus offering a novel therapeutic approach to the treatment of chronic renal failure.

Erythrocyte membrane with CLIPPKF as biomimetic nanodecoy traps merozoites and attaches to infected red blood cells to prevent Plasmodium infection.

BACKGROUND: Malaria remains a serious threat to global public health. With poor efficacies of vaccines and the emergence of drug resistance, novel strategies to control malaria are urgently needed. RESULTS: We developed erythrocyte membrane-camouflaged nanoparticles loaded with artemether based on the growth characteristics of Plasmodium. The nanoparticles could capture the merozoites to inhibit them from repeatedly infecting normal erythrocytes, owing to the interactions between merozoites and heparin-like molecules on the erythrocyte membrane. Modification with a phosphatidylserine-targeting peptide (CLIPPKF) improved the drug accumulation in infected red blood cells (iRBCs) from the externalized phosphatidylserine induced by Plasmodium infection. In Plasmodium berghei ANKA strain (pbANKA)-infected C57BL/6 mice, the nanoparticles significantly attenuated Plasmodium-induced inflammation, apoptosis, and anemia. We observed reduced weight variation and prolonged survival time in pbANKA-challenged mice, and the nanoparticles showed good biocompatibility and negligible cytotoxicity. CONCLUSION: Erythrocyte membrane-camouflaged nanoparticles loaded with artemether were shown to provide safe and effective protection against Plasmodium infection.

Impact on Carbon Intensity of Carbon Emission Trading-Evidence from a Pilot Program in 281 Cities in China.

China's carbon emissions trading scheme (ETS) is an institutional arrangement that China intends to explore as a means of energy conservation and emission reduction. It is the core of China's goal of achieving carbon peaking and carbon neutrality. This paper regards the introduction of pilot carbon emission trading policies as a quasi-natural experiment. Propensity Score Matching (PSM), Differences-in-Differences (DID), and spatial Durbin methods were used to evaluate the policy effects of pilot carbon emission trading policies on the carbon intensity of Chinese cities. We empirically tested the impact mechanism using the panel data of 281 cities at the prefecture level and above in China from 2006 to 2019. The results show that (1) the pilot policy of carbon emission trading has significantly reduced the carbon intensity of Chinese cities and shows characteristics of heterogeneity; (2) the dynamic effect test shows that the mitigation effect of the pilot carbon emission trading policy has increased gradually with time; (3) the mediation effect shows that the pilot carbon emission trading policy alleviates urban pollution in the region by improving the level of environmental governance and jointly reduces urban carbon intensity by increasing the level of green technology innovation; (4) the Durbin test suggests that pilot carbon emissions trading policy enforcement can significantly improve the carbon intensity of the area surrounding the city. In summary, the national carbon emissions trading market appears to be a successful experiment that also can contribute to China's sustainable development. Its promise in achieving the "double carbon" target provides important policy implications.

Chinese Medicine Formula PSORI-CM02 Alleviates Psoriatic Dermatitis via M-MDSCs and Th17 Crosstalk.

Psoriasis is a chronic inflammatory skin disease that is associated with multiple coexisting conditions. Extensive literature suggests that psoriasis is a T-cell-mediated condition, and its pathogenesis is related to dysfunction of the immune system. Myeloid-derived suppressor cells (MDSCs) are a group of heterogeneous myeloid cells that have suppressive effects on T cells. MDSCs are present at very low levels in healthy individuals but can substantially expand in tumours or inflammatory conditions. PSORI-CM02, a Chinese medical formula designed based on the Chinese medicine theory (Blood Stasis), has been prescribed extensively for psoriasis therapy and shows a stable clinical effect and safety. This study discusses the mechanisms of MDSCs involved in disease development and therapeutic progress. Our data provides evidence that monocytic myeloid-derived suppressor cells (M-MDSCs) play a role in IMQ-induced psoriatic dermatitis. Functional characterization and correlation analysis indicated that MDSCs are positively correlated with Th17 cells. PSORI-CM02 alleviated IMQ-induced psoriatic dermatitis and suppressed the proliferation of Th17 cells via M-MDSC-induced Arg1 upregulation, suggesting M-MDSCs could be a novel therapeutic target for psoriasis, and PSORI-CM02 exerted its effects via the perturbation of M-MDSCs and Th17 cell crosstalk.

PSORI-CM02 alleviates IMQ-induced mouse dermatitis via differentially regulating pro- and anti-inflammatory cytokines targeting of Th2 specific transcript factor GATA3.

The IL-17-producing CD4+ T cell and γδT cells play critical roles in the pathogenesis of psoriasis (PS). PSORI-CM02 is a representative herbal formula for the treatment for PS in South China. It was confirmed to improve PS without obvious side effects in the clinic. Here we sought to clarify whether and how PSORI-CM02 regulates T cell differentiation and functions in IMQ-induced psoriasis-like BALB/c mouse model. Mice pre-treated 3 days with PSORI-CM02 significantly alleviated skin inflammation, as reduced in PASI score and classic psoriatic characteristics in pathological sections. CD3 and CD4 positive T cells were also fewer in the skin lesions of PSORI-CM02 groups, comparing to control group. PSORI-CM02 also decreased pro-inflammatory IFNγ mRNA and IL-17 A mRNA, while increased IL-4 mRNA in mouse skin lesions. In skin draining lymph nodes (DLN), PSORI-CM02 reduced the ratio of γδT cells and inhibited their function of producing IL-17 A. Nevertheless PSORI-CM02 had no effects on the ratio of total TCRß+T cells and CD4 + T cells. But it regulated CD4 + T helper cells differentiation, and resulted in the decreasing percentage of IFNγ producing Th1 cells and IL-17 A producing Th17 cells, while increasing the ratio of IL-4 producing Th2 cells in DLN. Further data showed that PSORI-CM02 promote expression of Th2 specific transcript factor GATA3, but had no effects on T-bet and RORγ. Thus, we tentatively interpret that PSORI-CM02 impairs IMQ-induced psoriasis by promoting Th2 cell response targeting of GATA3.

Effects of Cigarette Smoking on Transplant Survival: Extending or Shortening It?

Cigarette smoking (CS) regulates both innate and adaptive immunity and causes numerous diseases, including cardiovascular, respiratory, and autoimmune diseases, allergies, cancers, and transplant rejection. Therefore, smoking poses a serious challenge to the healthcare system worldwide. Epidemiological studies have always shown that CS is one of the major risk factors for transplant rejection, even though smoking plays redundant roles in regulating immune responses. The complex roles for smoking in immunoregulation are likely due to molecular and functional diversities of cigarette smoke components, including carbon monoxide (CO) and nicotine. Especially, CO has been shown to induce immune tolerance. Although CS has been shown to impact transplantation by causing complications and subsequent rejection, it is overlooked whether CS interferes with transplant tolerance. We have previously demonstrated that cigarette smoke exposure reverses long-term allograft survival induced by costimulatory blockade. Given that CS impacts both adaptive and innate immunity and that it hinders long-term transplant survival, our perspective is that CS impacts transplant tolerance. Here, we review impacts of CS on major immune cells that are critical for transplant outcomes and propose the cellular and molecular mechanisms underlying its effects on alloimmunity and transplant survival. Further investigations are warranted to fully understand why CS exerts deleterious rather than beneficial effects on transplant survival even if some of its components are immunosuppressive.

Can active components of licorice, glycyrrhizin and glycyrrhetinic acid, lick rheumatoid arthritis?

OBJECTIVES: This review stated the possible application of the active components of licorice, glycyrrhizin (GL) and glycyrrhetinic acid (GA), in rheumatoid arthritis (RA) treatment based on the cyclooxygenase (COX)-2/thromboxane A2 (TxA2) pathway. METHODS: The extensive literature from inception to July 2015 was searched in PubMed central, and relevant reports were identified according to the purpose of this study. RESULTS: The active components of licorice GL and GA exert the potential anti-inflammatory effects through, at least in part, suppressing COX-2 and its downstream product TxA2. Additionally, the COX-2/TxA2 pathway, an auto-regulatory feedback loop, has been recently found to be a crucial mechanism underlying the pathogenesis of RA. However, TxA2 is neither the pharmacological target of non-steroidal anti-inflammatory drugs (NSAIDs) nor the target of disease modifying anti-rheumatic drugs (DMARDs), and the limitations and side effects of those drugs may be, at least in part, attributable to lack of the effects on the COX-2/TxA2 pathway. Therefore, GL and GA capable of targeting this pathway hold the potential as a novel add-on therapy in therapeutic strategy, which is supported by several bench experiments. CONCLUSIONS: The active components of licorice, GL and GA, could not only potentiate the therapeutic effects but also decrease the adverse effects of NSAIDs or DMARDs through suppressing the COX-2/TxA2 pathway during treatment course of RA.

Determination of role of thromboxane A2 in rheumatoid arthritis.

INTRODUCTION: To date, the etiology of rheumatoid arthritis (RA) remains largely unknown, and the therapies are still unsatisfactory. The biosynthesis of thromboxane A2 (TxA2) is increased in RA patients, suggesting a role of TxA2 in RA pathology. METHODS: RA patients were divided into two groups, DMARDs and non-DMARDs, according to their use of disease-modifying antirheumatic drugs (DMARDs). Sera from RA patients and healthy controls were extracted and subjected to enzyme immunoassays for measurement of the thromboxane B2 (TxB2) level. The statistical correlations between serum TxB2 levels and disease activity score of 28 joints (DAS28), C-reactive protein (CRP), or erythrocyte sedimentation rate (ESR) were calculated. Moreover, the effects of dual TxA2 modulator BM567 on cell proliferation as well as protein expression of α-actinin and NF-κB2 in RA fibroblast-like synovial (FLS) cells MH7A were determined by MTS assays and Western blot analysis, respectively. The effects of BM567 on mRNA expression of cyclooxygenase (COX)-2, a downstream product of NF-κB2 and an upstream enzyme of TxA2, was examined by real-time quantitative PCR experiments. RESULTS: Serum TxB2 level was significantly higher in RA patients as compared to healthy controls. Both DAS28 score and serum TxB2 levels were slightly lower in the DMARDs group than the non-DMARDs group, without statistical significance, and there was positive correlation between these two factors. BM567 significantly suppressed cell proliferation as well as expression of α-actinin, NF-κB2, p52, and COX-2 in MH7A. CONCLUSION: TxA2 plays an important role in RA pathology, synovial cell proliferation in particular, through an auto-regulatory feedback loop. Thus, targeting TxA2 may represent a promising add-on therapy in the treatment of RA.