Insulin-Like Growth Factor Binding Proteins in Autoimmune Diseases

Insulin-like growth factor binding proteins (IGFBPs) are a family of proteins binding to Insulin-like growth factors (IGFs), generally including IGFBP1, IGFBP2, IGFBP3, IGFBP4, IGFBP5, and IGFBP6. The biological functions of IGFBPs can be classified as IGFs-dependent actions and IGFs-independent effects. In this review, we will discuss the structure and function of various IGFBPs, particularly IGFBPs as potential emerging biomarkers and therapeutic targets in various autoimmune diseases, and the possible mechanisms by which IGFBPs act on the pathogenesis of autoimmune diseases

Identification of Renal Long Non-coding RNA RP11-2B6.2 as a Positive Regulator of Type I Interferon Signaling Pathway in Lupus Nephritis

Objective: Lupus nephritis (LN) is one of the most serious complications of systemic lupus erythematosus (SLE). Type I interferon (IFN-I) is associated with the pathogenesis of LN. Long non-coding RNAs (lncRNAs) have been implicated in the pathogenesis of SLE, however, the roles of lncRNAs in LN are still poorly understood. Here, we identified and investigated the function of LN-associated lncRNA RP11-2B6.2 in regulating IFN-I signaling pathway.Methods: RNA sequencing was used to analyze the expression of lncRNAs in kidney biopsies from LN patients and controls. Antisense oligonucleotides and CRISPRi system or overexpression plasmids and CRISPRa system were used to perform loss or gain of function experiments. In situ hybridization, imaging flow cytometry, dual-luciferase reporter assay, and ATAC sequencing were used to study the functions of lncRNA RP11-2B6.2. RT-qPCR, ELISA, and western blotting were done to detect RNA and protein levels of specific genes.Results: Elevated lncRNA RP11-2B6.2 was observed in kidney biopsies from LN patients and positively correlated with disease activity and IFN scores. Knockdown of lncRNA RP11-2B6.2 in renal cells inhibited the expression of IFN stimulated genes (ISGs), while overexpression of lncRNA RP11-2B6.2 enhanced ISG expression. Knockdown of LncRNA RP11-2B6.2 inhibited the phosphorylation of JAK1, TYK2, and STAT1 in IFN-I pathway, while promoted the chromatin accessibility and the transcription of SOCS1.Conclusion: The expression of lncRNAs is abnormal in the kidney of LN. LncRNA RP11-2B6.2 is a novel positive regulator of IFN-I pathway through epigenetic inhibition of SOCS1, which provides a new therapeutic target to alleviate over-activated IFN-I signaling in LN

TLR7 gain-of-function genetic variation causes human lupus

Although circumstantial evidence supports enhanced Toll-like receptor 7 (TLR7) signalling as a mechanism of human systemic autoimmune disease evidence of lupus-causing TLR7 gene variants is lacking. Here we describe human systemic lupus erythematosus caused by a TLR7 gain-of-function variant. TLR7 is a sensor of viral RNA and binds to guanosine. We identified a de novo, previously undescribed missense TLR7Y264H variant in a child with severe lupus and additional variants in other patients with lupus. The TLR7Y264H variant selectively increased sensing of guanosine and 2',3'-cGMP1 and was sufficient to cause lupus when introduced into mice. We show that enhanced TLR7 signalling drives aberrant survival of B cell receptor (BCR)-activated B cells, and in a cell-intrinsic manner, accumulation of CD11c+ age-associated B cells and germinal centre B cells. Follicular and extrafollicular helper T cells were also increased but these phenotypes were cell-extrinsic. Deficiency of MyD88 (an adaptor protein downstream of TLR7) rescued autoimmunity, aberrant B cell survival, and all cellular and serological phenotypes. Despite prominent spontaneous germinal-centre formation in Tlr7Y264H mice, autoimmunity was not ameliorated by germinal-centre deficiency, suggesting an extrafollicular origin of pathogenic B cells. We establish the importance of TLR7 and guanosine-containing self-ligands for human lupus pathogenesis, which paves the way for therapeutic TLR7 or MyD88 inhibition

The utility of urinary biomarker panel in predicting renal pathology and treatment response in Chinese lupus nephritis patients.

Given the urgent need for non-invasive biomarkers of LN, we aim to identify novel urinary biomarkers that facilitate diagnosis, assessment of disease activity and prediction of treatment response in a retrospective SLE cohort. A total of 154 SLE patients and 55 healthy controls were enrolled, among whom 73 were active LN patients. We measured renal activity by renal SLEDAI. The treatment response of the active LN patients who finished 6-month induction therapy was assessed based on the American College of Rheumatology response criteria. The expression levels of 10 urinary biomarkers (UBMs): β2-MG, calbindin D, cystatin C, IL-18, KIM-1, MCP-1, nephrin, NGAL, VCAM-1, and VDBP were tested using Luminex high-throughput proteomics technology. All but urinary nephrin levels were significantly increased in active LN compared to healthy controls. uCystatinC, uMCP-1, uKIM-1 levels were significantly higher in active LN group compared to inactive LN group. Correlation analysis revealed positive correlation between uCystatinC, uKIM-1, uMCP-1, uNGAL, uVDBP and RSLEDAI score. In renal pathology, uCystatinC, uKIM-1, uVCAM-1, and uVDBP positively correlated with activity index (AI) while uVCAM-1 positively correlated with chronicity index (CI). Moreover, the combination of uVCAM-1, uCystatinC, uKIM-1 discriminated proliferative LN from membranous LN with an AUC of 0.80 (95%CI: 0.69-0.90). Most importantly, baseline uNGAL demonstrated good prediction ability to discriminate responders from non-responders in active LN patients after 6-month induction therapy. Using a multiplex bead technique, we have identified the combination of uVCAM-1, uCystatinC, uKIM-1 as a biomarker panel to reflect renal pathology and NGAL as a promising urinary biomarker to both reflect disease activity and predict treatment response

Low Dose Epigallocatechin Gallate Alleviates Experimental Colitis by Subduing Inflammatory Cells and Cytokines, and Improving Intestinal Permeability

Background: In this study, we investigate the impact of epigallocatechin gallate (EGCG), the most abundant and potent catechin in green tea, on a mouse model of inflammatory bowel disease (IBD) and the underlying mechanisms of action. Methods: C57BL/6J mice were subjected to dextran sulfate sodium (DSS)-induced IBD-like disease and then randomly divided into three groups: Model group (MD), low-dose EGCG group (LE, 20 mg/kg/d), and high-dose EGCG group (HE, 50 mg/kg/d). DSS-induced clinical and macroscopic changes were monitored daily. Intestinal permeability was assessed by FITC-Dextran assay. Results: Both high- and low-dose EGCG treatment alleviated clinical manifestations including body weight loss and disease activity index (DAI) of DSS-induced colitis. The DAI score was significantly improved after two days of EGCG treatment. At the end of the study, the macroscopic severity score (MSS) of HE and LE treatment groups were 2.4 ± 1.2, and 2.2 ± 1.0, respectively, significantly lower than that of the controls (5.0 ± 2.1). EGCG treatment also prevented colon shortening, and improved intestinal permeability and histopathological changes. In addition, EGCG treatment attenuated colon inflammation by suppressing colonic levels of pro-inflammatory cytokines IL-6, MCP-1, and TNF-alpha, and inhibited CD3+ T cell and CD68+ macrophage infiltration. Conclusion: EGCG is effective in inflammatory colitis because it reduces cellular and molecular inflammation, and reduces intestinal permeability

HGF and BFGF Secretion by Human Adipose-Derived Stem Cells Improves Ovarian Function During Natural Aging via Activation of the SIRT1/FOXO1 Signaling Pathway

Background/Aims: Human adipose-derived stem cells (hADSCs) are a potential therapeutic option for clinical applications because of their ability to produce cytokines and their capacity for trilineage differentiation. To date, few researchers have investigated the effects of hADSCs on natural ovarian aging (NOA). Methods: An NOA mouse model and human ovarian granule cells (hGCs) collected from individuals with NOA were prepared to assess the therapeutic effects and illuminate the mechanism of hADSCs in curing NOA. Enzyme-linked immunosorbent assay was used to detect the serum levels of sex hormones and antioxidative enzymes. The proliferation rate and marker expression level of hGCs were measured by flow cytometry (FACS). Cytokines were measured by a protein antibody array methodology. Western blot assays were used to determine the protein expression levels of SIRT1 and FOXO1. Results: Our results showed that hADSCs displayed therapeutic activity against ovarian function in an NOA mouse model, increasing the proliferation rate and marker expression level of hGCs. Furthermore, the yields of hADSC-secreted HGF and bFGF were higher than those of other growth factors. FACS showed that combination treatment with the growth factors HGF and bFGF more strongly promoted proliferation and inhibited apoptosis in hGCs than HGF or bFGF treatment alone. FACS and ELISA revealed that the combination treatment with both growth factors inhibited oxidative stress more forcefully than treatments with only one of these growth factors. In addition, protein assays demonstrated that combination treatment with both growth factors suppressed oxidative stress by up-regulating the expression of SIRT1 and FOXO1. Conclusion: These findings demonstrate for the first time the molecular cascade and related cell biology events involved in the mechanism by which HGF and bFGF derived from hADSCs improved ovarian function during natural aging via reduction of oxidative stress by activating the SIRT1/FOXO1 signaling pathway

Bradykinin 1 receptor blockade subdues systemic autoimmunity, renal inflammation, and blood pressure in murine lupus nephritis

Abstract Objective The goal of this study was to explore the role of bradykinins and bradykinin 1 receptor (B1R) in murine lupus nephritis. Methods C57BL/6 and MRL/lpr mice were compared for renal expression of B1R and B2R by western blot and immunohistochemistry. MRL/lpr lupus-prone mice were administered the B1R antagonist, SSR240612 for 12 weeks, and monitored for blood pressure, proteinuria, renal function, and serum autoantibodies. Results Renal B1R:B2R ratios were significantly upregulated in MRL/lpr mice compared with B6 controls. B1R blockade ameliorated renal pathology lesions, proteinuria, and blood pressure, accompanied by lower serum IgG and anti-dsDNA autoantibody levels, reduced splenic marginal zone B cells and CD4+ T cells, and renal infiltrating CD4+ T cells, macrophages, and neutrophils. Both urine and renal CCL2 and CCL5 chemokines were also decreased in the B1R blocked MRL/lpr mice. Conclusion Bradykinin receptor B1R blockade ameliorates both systemic immunity and renal inflammation possibly by inhibiting multiple chemokines and renal immune cell infiltration. B1R blockade may be particularly attractive in subjects with concomitant lupus nephritis and hypertension

Synthesis of (R)-Mellein by a partially reducing iterative polyketide synthase

Mellein and the related 3,4-dihydroisocoumarins are a family of natural products with interesting biological properties. The mechanisms of dihydroisocoumarin biosynthesis remain largely speculative today. Here we report the synthesis of mellein by a partially reducing iterative polyketide synthase (PR-PKS) as a pentaketide product. Remarkably, despite the head-to-tail homology shared with several fungal and bacterial PR-PKSs, the mellein synthase exhibits a distinct keto reduction pattern in the synthesis of the pentaketide. We present evidence to show that the ketoreductase (KR) domain alone is able to recognize and differentiate the polyketide intermediates, which provides a mechanistic explanation for the programmed keto reduction in these PR-PKSs

Single-Cell Sequencing Reveals an Intrinsic Heterogeneity of the Preovulatory Follicular Microenvironment

The follicular microenvironment, including intra-follicular granulosa cells (GCs), is responsible for oocyte maturation and subsequent ovulation. However, the functions of GCs and cellular components of the follicular microenvironment in preovulatory follicles have not been extensively explored. Here, we surveyed the single-cell transcriptome of the follicular microenvironment around MII oocytes in six human preovulatory follicles in in vitro fertilization. There were six different cell types in the preovulatory follicles, including GCs and various immune cells. In GCs, we identified nine different functional clusters with different functional transcriptomic profiles, including specific clusters involved in inflammatory responses and adhesive function. Follicular macrophages are involved in immune responses, extracellular matrix remoulding and assist GCs in promoting the oocyte meiotic resumption. Interestingly, we observed that the specific terminal state subcluster of GCs with high levels of adhesive-related molecules should result in macrophage recruitment and residence, further contributing to an obvious heterogeneity of the immune cell proportion in preovulatory follicles from different patients. Our results provide a comprehensive understanding of the transcriptomic landscape of the preovulatory follicular microenvironment at the single-cell level. It provides valuable insights into understanding the regulation of the oocyte maturation and ovulation process, offering potential clues for the diagnosis and treatment of oocyte-maturation-related and ovulation-related diseases