Sweet taste receptors play roles in artificial sweetener-induced enhanced urine output in mice.

Sweet taste receptors found in oral and extra oral tissues play important roles in the regulation of many physiological functions. Studies have shown that urine volume increases during the lifetime exposure to artificial sweeteners. However, the detailed molecular mechanism and the general effects of different artificial sweeteners exposure on urine volume remain unclear. In this study, we investigated the relationship between urinary excretion and the sweet taste receptor expression in mice after three artificial sweeteners exposure in a higher or lower concentration via animal behavioral studies, western blotting, and real-time quantitative PCR experiment in rodent model. Our results showed that high dose of acesulfame potassium and saccharin can significantly enhance the urine output and there was a positive correlation between K+ and urination volume. The acesulfame potassium administration assay of T1R3 knockout mice showed that artificial sweeteners may affect the urine output directly through the sweet taste signaling pathway. The expression of T1R3 encoding gene can be up-regulated specifically in bladder but not in kidney or other organs we tested. Through our study, the sweet taste receptors, distributing in many tissues as bladder, were indicated to function in the enhanced urine output. Different effects of long-term exposure to the three artificial sweeteners were shown and acesulfame potassium increased urine output even at a very low concentration.

Sucralose regulates postprandial blood glucose in mice through intestinal sweet taste receptors Tas1r2/Tas1r3.

BACKGROUND: Non-nutritive sweeteners (such as sucralose) bind to sweet receptors Tas1r2/Tas1r3 on intestinal endocrine L cells after diets to upregulate blood glucose. However, the mechanism by which sucralose regulates postprandial blood glucose (PBG) has not been clarified to date. We hypothesized that the gut sweet taste receptor was one of the targets for sucralose to regulate PBG. The aim of this study was to examine the effect of sucralose on PBG based on the gut sweet taste receptor signaling pathway and to explore the mechanism. Therefore, we examined PBG, genes, and proteins associated with the gut sweet receptor pathway in sucralose-exposed mice. RESULTS: The results showed that after 12 weeks of sucralose exposure the PBG of mice increased significantly, and the expression of intestinal sweet taste receptors increased correspondingly. Within the concentration range of this experiment, a significant increase of PBG was observed in mice fed on sucralose with a concentration equal to or higher than 0.33 g L-1 . CONCLUSION: Long-term consumption of sucralose may increase body weight and the risk of elevated PBG, resulting in overexpression of sweetness receptors and glucose transporters. The mechanism of these effects might be the result of non-nutritive sweeteners binding to sweetness receptors Tas1r2/Tas1r3 in gut endocrine cells and upregulating Slc5a1 and Slc2a2. But we cannot rule out that the rise in PBG is the result of a combination of sweet receptors and gut microbes. Therefore, the effect of gut microbes on PBG needs to be studied further. © 2023 Society of Chemical Industry.

Meeting report: Xenotransplantation Development Conference in Neijiang, China.

A conference on progress in the development of xenotransplantation in China was held in Neijiang, Sichuan, in May 2023, and was attended by approximately 100 established researchers and trainees. Progress in xenotransplantation research was reviewed by both Chinese and foreign experts. The topics discussed ranged from genetic engineering of pigs and the results of pig-to-nonhuman primate organ transplantation to the requirements for designated pathogen-free (DPF) pig facilities and regulation of xenotransplantation. This conference served as an opportunity to collectively advance the development of xenotransplantation in China and pave the way for its clinical application.

Bonding Behavior of Cement Mortar Retrofitting for Adobe Masonry Wallette with Groove, Wire Mesh, Shear Dowel, and Sticky Rice Paste.

Damaged adobe masonry is essential to retrofit not only for continued use by less developed populations but also for historical preservation and vernacular landmark maintenance. Coating mortar on adobe can greatly improve the static load-carrying capacity of adobe masonry Wallette. Four retrofitting methods are carried out to enhance the cooperation of mortar and adobe; these four methods focus on the factors of roughness, shear dowel, and mesh size and a novel biological and traditional Chinese binder, sticky rice pulp. The mortar coating with the four bonding enhancement methods can greatly increase both the compressive and lateral load-carrying capacities, with a maximum improvement of 177 and 743%, respectively. The bonding strength has a negative effect on the compressive load-carrying capacity; on the other hand, it has a positive effect on the lateral load-carrying capacity. A range analysis is also carried out, which shows that the shear dowel depth has the greatest effect on both load situations, followed by the wire mesh size.

Advantages of the retroperitoneal retrocolic space as the transplant site for encapsulated xenogeneic islets.

OBJECTIVE: Islet allotransplantation has demonstrated improved clinical outcomes using the hepatic portal vein as the standard infusion method. However, the current implantation site is not ideal due to the short-term thrombotic and long-term immune destruction. Meanwhile, the shortage of human organ donors further limits its application. To find a new strategy, we tested a new polymer combination for islet encapsulation and transplantation. Meanwhile, we explored a new site for xenogeneic islet transplantation in mice. METHOD: We synthesized a hydrogel combining alginate plus poly-ethylene-imine (Alg/PEI) for the encapsulation of rat, neonatal porcine, and human islets. Transplantation was performed into the retroperitoneal retro-colic space of diabetic mice. Control mice received free islets under the kidney capsule or encapsulated islets into the peritoneum. The biochemical indexes were measured, and the transplanted islets were harvested for immunohistochemical staining of insulin and glucagon. RESULTS: Mice receiving encapsulated rat, porcine and human islets transplanted into the retroperitoneal space maintained normoglycemia for a median of 275, 145.5, and 146 days, respectively. In contrast, encapsulated xenogeneic islets transplanted into the peritoneum, maintained function for a median of 61, 95.5, and 82 days, respectively. Meanwhile, xenogeneic islets transplanted free into the kidney capsule lost their function within 3 days after transplantation. Immunohistochemical staining of encapsulated rat, porcine and human islets, retrieved from the retroperitoneal space, allowed to distinguish morphological normal insulin expressing ß- and glucagon expressing α-cells at 70, 60, and 100 days post-transplant, respectively. CONCLUSION: Transplantation of Alg/PEI encapsulated xenogeneic islets into the retroperitoneal space provides a valuable new implantation strategy for the treatment of type 1 diabetes.

Hsa_circ_0017728 as an oncogene in gastric cancer by sponging miR-149 and modulating the IL-6/STAT3 pathway.

Introduction: Circular RNAs (circRNAs) have been identified as competing endogenous RNAs (ceRNAs) to mediate gene expression participating in the progression of multiple cancers, including gastric carcinoma (GC). However, the underlying molecular mechanisms by which circRNAs-modulated cell proliferation and apoptosis in GC had not been completely clarified. In our study, hsa_circ_0017728 as a potential oncogene competing endogenous RNA (ceRNA) was investigated in the progression and development of gastric carcinogenesis. Material and methods: High-throughput sequencing was used to determine differentially expressed circRNAs in GC tissues and corresponding non-cancerous tissues. The CCK-8 assay and Annexin V-fluorescein isothiocyanate/polyimide (Annexin V-FITC/PI) staining were performed to detect the cell viability and apoptosis in GC cells. In addition, gene expression and protein levels in GC tissues and cell lines were measured using RT-qPCR and western blotting, respectively. Results: Our results demonstrated that the hsa_circ_0017728 expression level was up-regulated in GC tissues and cell lines and closely associated with poor overall survival and pathological differentiation, higher TNM stage and lymph node metastasis. Knockdown of hsa_circ_0017728 had the ability to cause inhibition of cell proliferation and migration and elevate the cell apoptosis rate in GC cells. We also discovered that hsa_circ_0017728 might serve as a ceRNA to sponge miR-149 and indirectly regulated the IL-6/STAT3 signaling pathway in GC cell proliferation and apoptosis. Conclusions: The regulatory network of hsa_circ_0017728/miR-149/IL-6/STAT3 cascade signaling might provide a better understanding of gastric carcinogenesis and progression.

In vivo induction of regulatory T cells by anti-CD45RB antibody causes transferable tolerance to discordant human xenogenic islets.

BACKGROUND: The treatment of diabetes by islet cell transplantation has become an accepted therapy, with transplantation of xenogeneic islet cells an attractive alternative to the problem. Previous studies in mice have demonstrated that anti-CD45RB induce immune tolerance in human pancreatic islet cells. The current study was to define the mechanism of action of anti-CD45RB induced nonspecific immune tolerance to heteroantigens. METHODS: A total of 1500 IEQ human islets were transplanted to diabetic B6µMT-/- mice, B6 mice, and µMT-/- diabetic mice undergoing thymectomy. These mice were treated short-term with doses of anti-CD45RB. CD4+Foxp3+Tregs were detected in the blood, peripheral lymphatic organs by flow cytometry, and immunohistochemistry. In addition, anti-CD25 mAb was administered to tolerant human islet cells B6µMT-/-mice. Mice then were transplanted with other human islet cells and received CD4+CD25+Tregs isolated from tolerant human islets mice to observe islet destruction. RESULTS: Anti-CD45RB treatment-induced tolerance to islets in both immunocompetent and B-cell-deficient mice (µMT-/- mice) by processes that were dependent on CD25+ Tregs, but not B cells. Anti-CD45RB treatment increased the number of CD4+Foxp3+Tregs cells. Anti-CD45RB treatment-induced immune tolerance that was antigen nonspecific, with Tregs playing an important role. Anti-CD45RB treatment-induced tolerance generated Tregs that could be transferred to another individual to manifest nonspecific immune tolerance. CONCLUSION: The results of the experiment suggest that anti-CD45RB induced tolerance to human islet xenografts is mediated by the proliferation of Tregs. These tolerogenic Tregs can be transferred to other mice and induce nonspecific immune tolerance.

Current status of xenotransplantation research and the strategies for preventing xenograft rejection.

Transplantation is often the last resort for end-stage organ failures, e.g., kidney, liver, heart, lung, and pancreas. The shortage of donor organs is the main limiting factor for successful transplantation in humans. Except living donations, other alternatives are needed, e.g., xenotransplantation of pig organs. However, immune rejection remains the major challenge to overcome in xenotransplantation. There are three different xenogeneic types of rejections, based on the responses and mechanisms involved. It includes hyperacute rejection (HAR), delayed xenograft rejection (DXR) and chronic rejection. DXR, sometimes involves acute humoral xenograft rejection (AHR) and cellular xenograft rejection (CXR), which cannot be strictly distinguished from each other in pathological process. In this review, we comprehensively discussed the mechanism of these immunological rejections and summarized the strategies for preventing them, such as generation of gene knock out donors by different genome editing tools and the use of immunosuppressive regimens. We also addressed organ-specific barriers and challenges needed to pave the way for clinical xenotransplantation. Taken together, this information will benefit the current immunological research in the field of xenotransplantation.

Anti-rheumatic drug-induced hepatitis B virus reactivation and preventive strategies for hepatocellular carcinoma.

To date, an estimated 300 million people worldwide have been infected with chronic hepatitis B virus (HBV). Although anti-HBV therapies have improved the long-term survival profile of chronic carriers, viral reactivation still poses a significant challenge for preventing HBV-related hepatitis, hepatocellular carcinoma (HCC), and death. Immuno-modulating drugs, which are widely applied in managing rheumatic conditions, are commonly associated with HBV reactivation (HBVr) as a result of drug-induced immune suppression. However, there are few reports on the risk of HBVr and the medication management plan for HBV carriers, especially rheumatic patients. In this review, we summarize immuno-modulating drug-induced HBVr during rheumatoid therapy and its preventive strategies for HBVr-induced liver diseases, especially cirrhosis and HCC. These findings will assist with developing treatments for rheumatic patients, and prevent HBV-related cirrhosis and HCC.

International Human Xenotransplantation Inventory: A 10-year Follow-up.

BACKGROUND: Following the recommendations by a panel of experts gathered by the World Health Organization in 2005, an inventory was established to collect practices of human xenotransplantation worldwide ( www.humanxenotransplant.org ). The website was activated in October 2006, in collaboration with the International Xenotransplantation Association, the University Hospital Geneva, and the World Health Organization. A first report on the collected xenotransplantation activities was published in 2010 in the journal Transplantation . In 2020, the website was redesigned, and its hosting and management were transferred to the Sichuan Provincial People's Hospital. METHODS: We collected information from publications in scientific journals, presentations at international congresses, the internet, and declarations of International Xenotransplantation Association members on xenotransplantation procedures in humans performed over the past 10 y. RESULTS: A total of 5 new applications of human xenotransplantation were identified, with pig as source animal in all applications. The procedures involved transplantation of islets of Langerhans, skin, cornea, and choroid plexus cells. The treatments were performed in China, United States, New Zealand, and Argentina. No major complications or deaths were reported. CONCLUSIONS: Several clinical applications of cell or tissue xenotransplantation are ongoing around the world. Compared with the previous reported period (1995-2010, with 29 activities, mostly without governmental regulation), the recent number of clinical activities was reduced, and all were officially approved. This information should be used to inform healthcare officials, staff, and the public with the objective of encouraging good practices based on internationally harmonized guidelines driven by initiatives such as the Changsha Communiqué.

Modifying strategies for SDF-1/CXCR4 interaction during mesenchymal stem cell transplantation.

Mesenchymal stem cell (MSC) transplantation is regarded as a promising candidate for the treatment of ischaemic heart disease. The major hurdles for successful clinical translation of MSC therapy are poor survival, retention, and engraftment in the infarcted heart. Stromal cell-derived factor-1/chemokine receptor 4 (SDF-1/CXCR4) constitutes one of the most efficient chemokine/chemokine receptor pairs regarding cell homing. In this review, we mainly focused on previous studies on how to regulate the SDF-1/CXCR4 interaction through various priming strategies to maximize the efficacy of mesenchymal stem cell transplantation on ischaemic hearts or to facilitate the required effects. The strengthened measures for enhancing the therapeutic efficacy of the SDF-1/CXCR4 interaction for mesenchymal stem cell transplantation included the combination of chemokines and cytokines, hormones and drugs, biomaterials, gene engineering, and hypoxia. The priming strategies on recipients for stem cell transplantation included ischaemic conditioning and device techniques.

Deficiency of ASGR1 in pigs recapitulates reduced risk factor for cardiovascular disease in humans.

Genetic variants in the asialoglycoprotein receptor 1 (ASGR1) are associated with a reduced risk of cardiovascular disease (CVD) in humans. However, the underlying molecular mechanism remains elusive. Given the cardiovascular similarities between pigs and humans, we generated ASGR1-deficient pigs using the CRISPR/Cas9 system. These pigs show age-dependent low levels of non-HDL-C under standard diet. When received an atherogenic diet for 6 months, ASGR1-deficient pigs show lower levels of non-HDL-C and less atherosclerotic lesions than that of controls. Furthermore, by analysis of hepatic transcriptome and in vivo cholesterol metabolism, we show that ASGR1 deficiency reduces hepatic de novo cholesterol synthesis by downregulating 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), and increases cholesterol clearance by upregulating the hepatic low-density lipoprotein receptor (LDLR), which together contribute to the low levels of non-HDL-C. Despite the cardioprotective effect, we unexpectedly observed mild to moderate hepatic injury in ASGR1-deficient pigs, which has not been documented in humans with ASGR1 variants. Thus, targeting ASGR1 might be an effective strategy to reduce hypercholesterolemia and atherosclerosis, whereas further clinical evidence is required to assess its hepatic impact.

An Unbiased Machine Learning Exploration Reveals Gene Sets Predictive of Allograft Tolerance After Kidney Transplantation.

Efforts at finding potential biomarkers of tolerance after kidney transplantation have been hindered by limited sample size, as well as the complicated mechanisms underlying tolerance and the potential risk of rejection after immunosuppressant withdrawal. In this work, three different publicly available genome-wide expression data sets of peripheral blood lymphocyte (PBL) from 63 tolerant patients were used to compare 14 different machine learning models for their ability to predict spontaneous kidney graft tolerance. We found that the Best Subset Selection (BSS) regression approach was the most powerful with a sensitivity of 91.7% and a specificity of 93.8% in the test group, and a specificity of 86.1% and a sensitivity of 80% in the validation group. A feature set with five genes (HLA-DOA, TCL1A, EBF1, CD79B, and PNOC) was identified using the BSS model. EBF1 downregulation was also an independent factor predictive of graft rejection and graft loss. An AUC value of 84.4% was achieved using the two-gene signature (EBF1 and HLA-DOA) as an input to our classifier. Overall, our systematic machine learning exploration suggests novel biological targets that might affect tolerance to renal allografts, and provides clinical insights that can potentially guide patient selection for immunosuppressant withdrawal.

Properties of regulatory B cells regulating B cell targets.

Regulatory B cells (Bregs) have shown promise as anti-rejection therapy applied to organ transplantation. However, less is known about their effect on other B cell populations that are involved in chronic graft rejection. We recently uncovered that naïve B cells, stimulated by TLR ligand agonists, converted into B cells with regulatory properties (Bregs-TLR) that prevented allograft rejection. Here, we examine the granular phenotype and regulatory properties of Breg-TLR cells suppressing B cells. Cocultures of Bregs-TLR with LPS-activated B cells showed a dose-dependent suppression of targeted B cell proliferation. Adoptive transfers of Bregs-TLR induced a decline in antibody responses to antigenically disparate skin grafts. The role of Breg BCR specificity in regulation was assessed using B cell-deficient mice replenished with transgenic BCR (OB1) and TCR (OT-II) lymphocytes of matching antigenic specificity. Results indicated that proliferation of OB1 B cells, mediated through help from CD4+ OT-II cells, was suppressed by OB1 Bregs of similar specificity. Transcriptomic analyses indicated that Bregs-TLR suppression is associated with a block in targeted B cell differentiation controlled by PRDM1 (Blimp1). This work uncovered the regulatory properties of a new brand of Breg cells and provided mechanistic insights into potential applications of Breg therapy in transplantation.

TGF-ß-secreting regulatory B cells: unsung players in immune regulation.

Regulatory B cells contribute to the regulation of immune responses in cancer, autoimmune disorders, allergic conditions and inflammatory diseases. Although most studies focus on regulatory B lymphocytes expressing interleukin-10, there is growing evidence that B cells producing transforming growth factor ß (TGF-ß) can also regulate T-cell immunity in inflammatory diseases and promote the emergence of regulatory T cells that contribute to the induction and maintenance of natural and induced immune tolerance. Most research on TGF-ß+ regulatory B cells has been conducted in models of allergy, cancer and autoimmune diseases, but there has, as yet, been limited scrutiny of their role in the transplant setting. Herein, we review recent investigations seeking to understand how TGF-ß-producing B cells direct the immune response in various inflammatory diseases and whether these regulatory cells may have a role in fostering tolerance in transplantation.

Sweet Taste Receptor Expression and Its Activation by Sucralose to Regulate Glucose Absorption in Mouse Duodenum.

Sucralose (SUC) has been used in the food industry for nearly 30 years since it was first allowed as an artificial sweetener at the end of the 20th century. However, its effects on the body remain not incontrovertible. This work aimed to investigate the influence of SUC exposure on sweetness receptors and glucose absorption and to explore the relationship between them. Mice were exposed with different concentration of SUC (from 0.27 to 0.47 g/L) for 12 weeks. Long-term treatment with SUC resulted in impaired glucose metabolism, manifested in the decrease of glucose tolerance and the increase of sweet taste receptors, glucose transporters, and glucose absorption. This study also provides a method to quantify the glucose absorptivity. In detail, with increasing concentration of SUC, the glucose absorptivities in the dodecadactylon of mice were added 1.48, 1.56, 1.71, and 1.71 times, respectively, showing wide interindividual variation compared with the control group. PRACTICAL APPLICATION: The artificial sweetener, sucralose, has physiological influences of changing glucose metabolism. The small bowel is the main location for glucose metabolism and absorbs the ingested proteins and carbohydrates. And, this study provides a method to quantify the glucose absorptivity of intestine.

Transplant Islets Into the Pinna of the Ear: A Mouse Islet Transplant Model.

BACKGROUND: Islets transplanted under the ear skin would allow easy observation of the graft response and survival in vivo. This research was designed to establish an efficient mouse islet transplant model to probe the dynamic cellular interplay in vivo. METHODS: Green fluorescent protein transgenic mice and BALB/c mice were used as donors and recipients. All recipients were divided into 6 groups of 6 mice each. First, we treated the transplant recipients, including diabetes induction, autologous epididymal fat pad, and MATRIGEL transplant to the ears. Then, 1. we transplanted isolated islets to the ear/ear with fat/ear with MATRIGEL; and 2. transplanted islets with collagen + basic fibroblast growth factor or islets with collagen + vascular endothelial growth factor. Mice in the control group received a sham transplantation with phosphate buffer saline. All recipients were then observed for 30 days with blood glucose (BG) monitoring. Finally, ears were removed with graft on day 28 for histologic examination. RESULTS: It was suggested that transplant of islets alone could not correct hyperglycemia. Fat, MATRIGEL, collagen, and growth factors have the similar function to form a microenvironment conducive to islet survival. The effect of islet transplantation for correcting hyperglycemia of the fat modification group was better than other groups (P < .05). BG could be normalized, and living islets were detected by anti-insulin immunohistochemistry. CONCLUSIONS: Transplant islets into the ear with transplanted autologous fat is the optimal way which can be used to analyze the allograft response in vivo and track cell population and migration using labels by confocal microscopy.