IL-21 promoting angiogenesis contributes to the development of psoriasis.

BACKGROUND: Elevated IL-21 expression which can effectively induce Th17 cell differentiation has been implicated in the pathogenesis of psoriasis, but its role in angiogenesis remains poorly understood. METHODS: PASI and PSI score assessment was applied to evaluate the severity of psoriatic lesions. The expression of IL-21, IL-21 receptor (IL-21R), CD31, VEGFA, MMP-9, and ICAM-1 in skin was determined by immunohistochemistry or quantitative real-time polymerase chain reaction. The serum level of IL-21 was measured by enzyme-linked immunosorbent assay (ELISA). Then, their correlation was analyzed statistically. Human umbilical vein endothelial cells (HUVECs) cocultured with conditional medium from normal human epidermal keratinocytes (NHEKs) were treated with IL-21 and/or M5 cocktail (mixture of IL-1α, IL-17A, IL-22, TNF-α, and oncostatin M). The migration and tube formation of HUVECs were detected, and the levels of VEGFA, MMP-9, and ICAM-1 in NHEKs were measured by Western blotting or ELISA. RESULTS: Increased IL-21 and IL-21R expression was observed in psoriatic sera or skin specimens, with IL-21R mainly locating in keratinocytes and IL-21 in immune cells. Pearson analysis showed significantly positive correlation between IL-21/IL-21R and erythema scores/microvessel density in psoriatic lesions. Moreover, the expression of proangiogenic genes, VEGFA, ICAM-1, and MMP-9 was upregulated in skins of psoriasis. Additionally, in M5 microenvironment, migration and tube formation could be magnified in HUVECs using IL-21 pre-treated NHEK medium. Mechanically, the co-stimulation of IL-21 and M5 to NEHKs increased the expression of ICAM-1. CONCLUSION: IL-21 could regulate keratinocytes to secrete ICAM-1, thereby promoting angiogenesis in psoriasis.

CD11b + CD43 hi Ly6C lo splenocyte-derived macrophages exacerbate liver fibrosis via spleen-liver axis.

BACKGROUND AND AIMS: Monocyte-derived macrophages (MoMFs), a dominant population of hepatic macrophages under inflammation, play a crucial role in liver fibrosis progression. The spleen serves as an extra monocyte reservoir in inflammatory conditions; however, the precise mechanisms of involvement of the spleen in the pathogenesis of liver fibrosis remain unclear. APPROACH AND RESULTS: By splenectomy and splenocyte transfusion, it was observed that splenic CD11b + cells accumulated intrahepatically as Ly6C lo MoMFs to exacerbate CCl 4 -induced liver fibrosis. The splenocyte migration into the fibrotic liver was further directly visualized by spleen-specific photoconversion with KikGR mice and confirmed by CD45.1 + /CD45.2 + spleen transplantation. Spleen-derived CD11b + cells purified from fibrotic livers were then annotated by single-cell RNA sequencing, and a subtype of CD11b + CD43 hi Ly6C lo splenic monocytes (sM-1s) was identified, which was markedly expanded in both spleens and livers of mice with liver fibrosis. sM-1s exhibited mature feature with high expressions of F4/80, produced much ROS, and manifested preferential migration into livers. Once recruited, sM-1s underwent sequential transformation to sM-2s (highly expressed Mif , Msr1 , Clec4d , and Cstb ) and then to spleen-derived macrophages (sMφs) with macrophage features of higher expressions of CX 3 CR1, F4/80, MHC class II, and CD64 in the fibrotic hepatic milieu. Furthermore, sM-2s and sMφs were demonstrated capable of activating hepatic stellate cells and thus exacerbating liver fibrosis. CONCLUSIONS: CD11b + CD43 hi Ly6C lo splenic monocytes migrate into the liver and shift to macrophages, which account for the exacerbation of liver fibrosis. These findings reveal precise mechanisms of spleen-liver axis in hepatic pathogenesis and shed light on the potential of sM-1 as candidate target for controlling liver diseases.

Protein folding dependence on selenoprotein M contributes to steady cartilage extracellular matrix repressing ferroptosis via PERK/ATF4/CHAC1 axis.

OBJECTIVE: Initiation of endoplasmic reticulum (ER) stress is pivotal to the advancement of osteoarthritis (OA). We aimed to explore the function of ER-resident selenoprotein M (SELM) in cartilage-forming chondrocytes, investigating how SELM participates in cartilage extracellular matrix (ECM) metabolism and ER stress modulation. METHODS: Articular cartilage samples with knee OA undergoing total knee arthroplasty were categorised into OA-smooth and OA-damaged groups, with primary chondrocytes extracted from smooth areas. Destabilization of the medial meniscus was induced in male C57BL6/J mice, with sham operations on the left knee as controls. After 8 weeks, knee joint tissues were collected for analysis. Histology and immunohistochemistry examined cartilage damage. Molecular biology techniques investigated how SELM affects ECM metabolism and ER stress regulation. RNA sequencing revealed the pathway changes after SELM intervention. AlphaFold demonstrated how SELM interacts with other molecules. Cultured cartilage explants helped determine the effects of SELM supplementation. RESULTS: SELM expression was reduced in the damaged cartilage. Increasing SELM levels positively impacted ECM equilibrium. Decreasing SELM expression activated genes linked to degenerative ailments and impaired the cellular response to misfolded proteins, initiating the PERK/P-EIF2A/ATF4 pathway and exacerbating GSH/GSSG imbalance via the ATF4/CHAC1 axis. SELM likely participated in protein folding and modification by leveraging its thioredoxin domains. In vitro SELM supplementation mitigated IL-1ß effects on damaged cartilage explants and suppressed beneficial chondrocyte phenotypes. CONCLUSIONS: Our results confirm the involvement of SELM in ER stress-induced cartilage damage as well as protein folding, pointing to new directions in molecular therapy for degenerative diseases.

LNCHC directly binds and regulates YBX1 stability to ameliorate metabolic dysfunction-associated steatotic liver disease progression.

BACKGROUND AND AIMS: Metabolic dysfunction-associated steatotic liver disease (MASLD) represents the foremost cause of chronic liver disease, yet its underlying mechanisms remain elusive. Our group previously discovered a novel long non-coding RNA (lncRNA) in rats, termed lncHC and its human counterpart, LNCHC. This study aimed to explore the role of LNCHC in the progression of MASLD. METHODS: RNA-binding proteins bound to LNCHC were searched by mass spectrometry. The target genes of LNCHC and Y-Box binding protein 1 (YBX1) were identified by RNA-seq. MASLD animal models were utilised to examine the roles of LNCHC, YBX1 and patatin-like phospholipase domain containing 3 (PNPLA3) in MASLD progression. RESULTS: Here, we identified LNCHC as a native restrainer during MASLD development. Notably, LNCHC directly binds YBX1 and prevents protein ubiquitination. Up-regulation of YBX1 then stabilises PNPLA3 mRNA to alleviate lipid accumulation in hepatocytes. Furthermore, both cell and animal studies demonstrate that LNCHC, YBX1 and PNPLA3 function to improve hepatocyte lipid accumulation and exacerbate metabolic dysfunction-associated steatohepatitis development. CONCLUSIONS: In summary, our findings unveil a novel LNCHC functionality in regulating YBX1 and PNPLA3 mRNA stability during MASLD development, providing new avenues in MASLD treatment.

Modulating the m6A Modified Transcription Factor GATA6 Impacts Epithelial Cytokines in Acute Lung Injury.

The methylation of m6A (N6-position of adenosine) has been found to be associated with inflammatory response. We hypothesize that m6A modification plays a role in the inflammation of airway epithelial cells during lung inflammation. However, the precise changes and functions of m6A modification in airway epithelial cells in acute lung injury (ALI) are not well understood. Here we report that METTL3 (methyltransferase-like 3)-mediated m6A of GATA6 (GATA-binding factor 6) mRNA inhibits ALI and the secretion of proinflammatory cytokines in airway epithelial cells. The expression of METTL3 and m6A levels decrease in lung tissues of mice with ALI. In cocultures, peripheral blood monocytes secreted TNF-α, which reduces METTL3 and m6A levels in the human bronchial epithelial cell line BEAS-2B. Knockdown of METTL3 promotes IL-6 and TNF-α release in BEAS-2B cells. Conversely, overexpression of METTL3 increases total RNA m6A level and reduces the levels of proinflammatory cytokines TNF-α, transforming growth factor-ß, and thymic stromal lymphopoietin. Increasing METTL3 in mouse lungs prevented LPS-induced ALI and reduced the synthesis of proinflammatory cytokines. Mechanistically, sequencing and functional analysis show that METTL3 catalyzes m6A in the 3' untranslated region of GATA6 read by YTH N6-Methyladenosine RNA Binding Protein 2 and triggers mRNA degradation. GATA6 knockdown rescues TNF-α-induced inflammatory cytokine secretion of epithelial cells, indicating that GATA6 is a main substrate of METTL3 in airway epithelial cells. Overall, this study provides evidence of a novel role for METTL3 in the inflammatory cytokine release of epithelial cells and provides an innovative therapeutic target for ALI.

SLC38A6 expression in macrophages exacerbates pulmonary inflammation.

Pulmonary inflammation involves complex changes of the immune cells, in which macrophages play important roles and their function might be influenced by metabolism. Slc38a6 acts as a carrier of nutrient for macrophages (Mφ) to exert the function. In this study, pneumonia patient blood was found up-regulated SLC38A6 expression, which correlated with monocytes number and white blood cell number. The similar result was also shown in LPS induced sepsis mice. To reveal the key role of Slc38a6, we used systemic and conditional knock-out mice. Either systemic or LyzCRE specific knock-out could alleviate the severity of sepsis mice, reduce the proinflammatory cytokine TNF-α and IL-1ß expression in serum and decrease the monocytes number in bronchial alveolar lavage and peritoneal lavage via flow cytometry. In order to reveal the signal of up-regulated Slc38a6, the Tlr4 signal inhibitor TAK242 and TLR4 knock-out mice were used. By blocking Tlr4 signal in macrophages via TAK242, the expression of Slc38a6 was down-regulated synchronously, and the same results were also found in Tlr4 knock-out macrophages. However, in the overexpressed Slc38a6 macrophages, blocking Tlr4 signal via TAK242, 20% of the mRNA expression of IL-1ß still could be expressed, indicating that up-regulated Slc38a6 participates in IL-1ß expression process. Collectively, it is the first time showed that an amino acid transporter SLC38A6 up-regulated in monocytes/macrophages promotes activation in pulmonary inflammation. SLC38A6 might be a promising target molecule for pulmonary inflammation treatment.

PRMT1 Modulates Processing of Asthma-Related Primary MicroRNAs (Pri-miRNAs) into Mature miRNAs in Lung Epithelial Cells.

Protein arginine methyltransferase-1 (PRMT1) is an important epigenetic regulator of cell function and contributes to inflammation and remodeling in asthma in a cell type-specific manner. Disease-specific expression patterns of microRNAs (miRNA) are associated with chronic inflammatory lung diseases, including asthma. The de novo synthesis of miRNA depends on the transcription of primary miRNA (pri-miRNA) transcript. This study assessed the role of PRMT1 on pri-miRNA to mature miRNA process in lung epithelial cells. Human airway epithelial cells, BEAS-2B, were transfected with the PRMT1 expression plasmid pcDNA3.1-PRMT1 for 48 h. Expression profiles of miRNA were determined by small RNA deep sequencing. Comparing these miRNAs with datasets of microarrays from five asthma patients (Gene Expression Omnibus dataset), 12 miRNAs were identified that related to PRMT1 overexpression and to asthma. The overexpression or knockdown of PRMT1 modulated the expression of the asthma-related miRNAs and their pri-miRNAs. Coimmunoprecipitation showed that PRMT1 formed a complex with STAT1 or RUNX1 and thus acted as a coactivator, stimulating the transcription of pri-miRNAs. Stimulation with TGF-ß1 promoted the interaction of PRMT1 with STAT1 or RUNX1, thereby upregulating the transcription of two miRNAs: let-7i and miR-423. Subsequent chromatin immunoprecipitation assays revealed that the binding of the PRMT1/STAT1 or PRMT1/RUNX1 coactivators to primary let-7i (pri-let-7i) and primary miR (pri-miR) 423 promoter was critical for pri-let-7i and pri-miR-423 transcription. This study describes a novel role of PRMT1 as a coactivator for STAT1 or RUNX1, which is essential for the transcription of pri-let-7i and pri-miR-423 in epithelial cells and might be relevant to epithelium dysfunction in asthma.

LncRNA WDR11-AS1 Promotes Extracellular Matrix Synthesis in Osteoarthritis by Directly Interacting with RNA-Binding Protein PABPC1 to Stabilize SOX9 Expression.

Osteoarthritis (OA) is a degenerative disease of articular cartilage that is mainly characterized by chronic and mild inflammation of the joints. Recently, many studies have reported the crucial roles of long noncoding RNAs (lncRNAs) in OA as gene transcriptional regulatory factors, diagnostic biomarkers, or therapeutic targets. However, the exact mechanisms of lncRNAs in the regulation of OA progression remain unclear. In the present study, the lncRNA WDR11 divergent transcript (lncRNA WDR11-AS1) was shown to be downregulated in osteoarthritic cartilage tissues from patients, and to promote extracellular matrix (ECM) synthesis in osteoarthritic chondrocytes with knockdown and overexpression experiments. This function of lncRNA WDR11-AS1 was linked to its ability to interact with the polyadenylate-binding protein cytoplasmic 1 (PABPC1), which was screened by RNA pulldown and mass spectrometry analyses. PABPC1 was discovered to bind ECM-related mRNAs such as SOX9, and the inhibition of PABPC1 improved the mRNA stability of SOX9 to mitigate OA progression. Our results suggest that lncRNA WDR11-AS1 has a promising inhibitory effect on inflammation-induced ECM degradation in OA by directly binding PABPC1, thereby establishing lncRNA WDR11-AS1 and PABPC1 as potential therapeutic targets in the treatment of OA.

SLC7A5 expression is up-regulated in peripheral blood T and B lymphocytes of systemic lupus erythematosus patients, associating with renal damage.

Metabolic reprogramming of immune cells has been proven to be important for systemic lupus erythematosus (SLE). This study aims to understand the role of SLC7A5, an amino acid transporter, in SLE. We analyzed SLC7A5 mRNA expression of SLE patients compared to healthy controls using GEO database, and found that it was increased in CD4+ T cells and CD19+ B cells. We then confirmed the expression up-regulation using flow cytometry and found that the proportion of SLC7A5+ cells and its expression were increased in peripheral blood T and B cells from SLE patients. Importantly, SLC7A5 expression in T and B cells was positively correlated with blood urea nitrogen and serum creatinine. Therefore, we conclude that SLC7A5, up-regulating in circulating T and B cells, correlates with kidney function, suggesting its potential role in mediating renal damage in SLE, which provides novel insight into SLE pathogenesis and provides a potential biomarker for disease.

Loss of microRNA-147 function alleviates synovial inflammation through ZNF148 in rheumatoid and experimental arthritis.

MicroRNA-147 (miR-147) had been previously found induced in synoviocytes by inflammatory stimuli derived from T cells in experimental arthritis. This study was designed to verify whether loss of its function might alleviate inflammatory events in joints of experimental and rheumatoid arthritis (RA). Dark Agouti (DA) rats were injected intradermally with pristane to induce arthritis, and rno-miR-147 antagomir was locally administrated into individual ankle compared with negative control or rno-miR-155-5p antagomir (potential positive control). Arthritis onset, macroscopic severity, and pathological changes were monitored. While in vitro, gain or loss function of hsa-miR-147b-3p/hsa-miR-155-5p and ZNF148 was achieved in human synovial fibroblast cell line SW982 and RA synovial fibroblasts (RASF). The expression of miRNAs and mRNAs was detected by using RT-quantitative PCR, and protein expression was detected by using Western blotting. Anti-miR-147 therapy could alleviate the severity, especially for the synovitis and joint destruction in experimental arthritis. Gain of hsa-miR-147b-3p/hsa-miR-155-5p function in TNF-α stimulated SW982 and RASF cells could upregulate, in contrast, loss of hsa-miR-147b-3p/hsa-miR-155-5p function could downregulate the gene expression of TNF-α, IL-6, MMP3, and MMP13. Hence, such alteration could participate in synovial inflammation and joint destruction. RNAi of ZNF148, a miR-147's target, increased gene expression of TNF-α, IL-6, MMP3, and MMP13 in SW982 and RASF cells. Also, mRNA sequencing data showed that hsa-miR-147b-3p mimic and ZNF148 siRNA commonly regulated the gene expression of CCL3 and DEPTOR as well as some arthritis and inflammation-related pathways. Taken together, miR-147b-3p contributes to synovial inflammation through repressing ZNF148 in RA and experimental arthritis.

Selenium-sensitive histone deacetylase 2 is required for forkhead box O3A and regulates extracellular matrix metabolism in cartilage.

INTRODUCTION: Selenium (Se) as well as selenoproteins are vital for osteochondral system development. Se deficiency (SeD) has a definite impact on the expression and activity of histone deacetylases (HDACs). Abnormal expression of some HDACs affects cartilage development. This current study aims to explore the relationship between differentially expressed HDACs and cartilage development, especially extracellular matrix (ECM) homeostasis maintenance, under SeD conditions. MATERIALS AND METHODS: Dark Agouti rats and C28/I2 cell line under SeD states were used to detect the differently expressed HDAC by RT-qPCR, western blotting and IHC staining. Meanwhile, the biological roles of the above HDAC in cartilage development and homeostasis maintenance were confirmed by siRNA transfection, western blotting, RNA sequence and inhibitor treatment experiments. RESULTS: HDAC2 exhibited lower expression at protein level in both animals and chondrocytes during SeD condition. The results of cell-level experiments indicated that forkhead box O3A (FOXO3A), which was required to maintain metabolic homeostasis of cartilage matrix, was reduced by HDAC2 knockdown. Meanwhile, induced HDAC2 was positively associated with FOXO3A in rat SeD model. Meanwhile, knockdown of HDAC2 and FOXO3A led to an increase of intracellular ROS level, which activated NF-κB pathway. Se supplementary significantly inhibited the activation of NF-κB pathway with IL-1ß treatment. CONCLUSION: Our results suggested that low expression of HDAC2 under SeD condition increased ROS content by decreasing FOXO3A in chondrocytes, which led to the activation of NF-κB pathway and ECM homeostasis imbalance.

Identification of benzamides derivatives of norfloxacin as promising microRNA-21 inhibitors via repressing its transcription.

MicroRNA-21 is a carcinogenic microRNA, whose overexpression arises in a variety of tumor tissues. Hence, microRNA-21 a prospective target for cancer treatment, and regulation of microRNA-21 by small molecule inhibitors is deemed as a promising approach for tumor therapy. In this work, to discover potent microRNA-21 inhibitor, series of 4-(N-norfloxacin-acyl)aminobenzamides were designed and synthesized, and their inhibitory effects were appraised by utilizing dual luciferase reporter assays. The results indicated that compound A7 was the most efficient microRNA-21 small molecule inhibitor. What's more, A7 suppressed the migration of Hela cells and the colony formation of Hela and HCT-116 cells as well as promoted apoptosis of Hela cells. In the mechanism study, results of RT-qPCR certified that A7 could reduce the level of mature microRNA-21 via disrupting its expression at the transcriptional level of its primary form "pri-miR-21", which was distinct from most previous inhibitors directly binding with pre-miR-21. Noticeably, Western blotting and RT-qPCR uncovered A7 could upregulate the expression PTEN, EGR1 and SLIT2, which are the downstream functional targets of microRNA-21. These findings demonstrated that A7 was a promising microRNA-21 small molecule inhibitor and 4-(N-norfloxacin-acyl) aminobenzamide can serve as a new scaffold for discovery of potent microRNA-21 inhibitor.

Upregulated PKM2 in Macrophages Exacerbates Experimental Arthritis via STAT1 Signaling.

Recent studies indicate that glucose metabolism is altered in rheumatoid arthritis. We hypothesize that Pkm2, as a key regulatory enzyme of glycolysis pathway, triggers the activation of macrophages (Mφ), which results in proinflammatory cytokine production during the arthritis progress. In this study, Pkm2 was found to be overexpressed in ED1-positive Mφ in spleens and synovial tissues from arthritic rats via immunofluorescence, Western blotting, and quantitative RT-PCR. To reveal the role of Pkm2, Dark Agouti rats were treated with either Pkm2 enzyme inhibitor shikonin or the RNA interference plasmids of Pkm2 and negative control plasmids, respectively, via i.p. injection. Pkm2 intervention could alleviate the severity of pristane-induced arthritis in aspects of the macroscopic arthritis score, perimeter changes of midpaw, and the synovitis and destruction of the bone and cartilage as well as reduce the ED1 and p-Stat1-positive cell population in rat synovial tissues. Silencing Pkm2 by RNA interference in classical activated rat and mouse Mφ resulted in less Tnf-α, Il-1ß production via Stat1 signaling. Collectively, Pkm2 is highly expressed in ED1-positive Mφ of spleens and synovial tissues from arthritic rats and promotes Mφ activation via Stat1 signaling. Pkm2 might be a promising selective metabolic target molecule for rheumatoid arthritis treatment.

Pristane promotes anaerobic glycolysis to facilitate proinflammatory activation of macrophages and development of arthritis.

Pristane-induced arthritis (PIA) could be adoptively transferred by splenic T cells in rats, and innate immunity should play critical roles in T cell activation. However, in pre-clinical stage, the activation mechanism of innate cells like macrophages remains unclear. Here we found that PIA was dependent on macrophages since cell depletion alleviated disease severity. Splenic macrophages of PIA rats showed M1 phenotypic shifting. The quantitative proteomics analysis suggested that macrophages initiated metabolic reprogramming with the conversion of aerobic oxidation to glycolysis in response to pristane in vivo. Notably, macrophages treated with pristane showed mitochondrial dysregulation and increased glycolysis flux and enzyme activity. Additionally, TNFα production, strongly associating with the glycolysis enzyme Ldha/Ldhb, could be reduced as glycolysis was inhibited or be enhanced as citrate cycle was blocked. This work provides detailed insights into the molecular mechanisms of pristane-mediated metabolic reprogramming in macrophages and suggests a new therapeutic strategy for arthritic disorders.

Topical Treatment of Colquhounia Root Relieves Skin Inflammation and Itch in Imiquimod-Induced Psoriasiform Dermatitis in Mice.

Itch is one of the major clinical manifestations of psoriasis, which is closely related with neurogenic inflammation and difficult to control. Colquhounia Root (CR) is a Chinese herb exhibiting broad bioactivities on anti-inflammation. This study was designed to explore the antipsoriatic and anti-itch potential of CR and its underlying mechanisms. Mice in a model of imiquimod-induced psoriasiform dermatitis were treated topically with CR for 7 days, and the severity of skin lesions and itch was significantly ameliorated. CR reduced the inflammatory cell infiltration, as well as mast cells in skins. Particularly, the expression of inflammatory cytokines and chemokine including Il17a, Il22, and Ccl20 and itch-related molecules such as SP, CGRP, and NGF in lesions were decreased in diseased mice upon application with CR. The normal human epidermal keratinocytes were stimulated with the M5 cytokine cocktail, the mixture of IL-17A, IL-22, Oncostatin M, IL-1α, and TNF-α, and cell viability and mRNA expression levels of inflammatory factors and itch-related molecules were measured after being treated with CR. We found that CR inhibited both cell hyperproliferation and overexpression of inflammatory cytokines and itch-related molecules in vitro. Altogether, we conclude that CR relieves psoriatic lesions and itch via controlling immunological and neurogenic inflammation.

Induction of PDCD4 by albumin in proximal tubule epithelial cells potentiates proteinuria-induced dysfunctional autophagy by negatively targeting Atg5.

Autophagy dysfunction is a hallmark of type 1 diabetes. However, the precise molecular mechanism of proteinuria-induced dysfunctional autophagy remains unclear. Herein, we investigated the role of programmed cell death 4 (PDCD4) in the regulation of autophagy in the pathogenesis of diabetic kidney disease (DKD) in vivo and in vitro. RT-qPCR, immunohistochemistry (IHC), and western blotting demonstrated an upregulation of Pdcd4 mRNA and protein in streptozotocin (STZ)-induced DKD rats, as compared to the control. In addition, IHC and western blotting of a unilateral ureteral obstruction mouse model showed an upregulation of PDCD4 in the disease group, as compared to their respective controls. IHC analysis of kidney biopsy samples of human DKD patients showed an upregulation of PDCD4 compared to the control. Western blotting of the STZ-induced DKD rat tissues displayed a low microtubule-associated protein 1A/1B-light chain 3 (LC3)-II, as compared to the control. It was found that albumin overload in cultured PTECs upregulated the expression of PDCD4 and p62 and decreased the expression of LC3-II and autophagy-related 5 (Atg5) proteins. The knockout of Pdcd4 in cultured PTECs could reduce albumin-induced dysfunctional autophagy, as evidenced by the recovery of Atg5 and LC3-II protein. The forced expression of PDCD4 could further suppress the expression of the crucial autophagy-related gene Atg5. Evidence suggests that endogenous PDCD4 promotes proteinuria-induced dysfunctional autophagy by negatively regulating Atg5. Therefore, PDCD4 may be a potential therapeutic target in DKD.

TGF-ß Upregulated Mitochondria Mass through the SMAD2/3→C/EBPß→PRMT1 Signal Pathway in Primary Human Lung Fibroblasts.

Tissue remodeling of subepithelial mesenchymal cells is a major pathologic condition of chronic obstructive pulmonary disease and asthma. Fibroblasts contribute to fibrotic events and inflammation in both airway diseases. Recent mechanistic studies established a link between mitochondrial dysfunction or aberrant biogenesis leading to tissue remodeling of the airway wall in asthma. Protein arginine methyltransferase-1 (PRMT1) participated in airway wall remodeling in pulmonary inflammation. This study investigated the mechanism by which PRMT1 regulates mitochondrial mass in primary human airway wall fibroblasts. Fibroblasts from control or asthma patients were stimulated with TGF-ß for up to 48 h, and the signaling pathways controlling PRMT1 expression and mitochondrial mass were analyzed. PRMT1 activity was suppressed by the pan-PRMT inhibitor AMI-1. The SMAD2/3 pathway was blocked by SB203580 and C/EBPß by small interference RNA treatment. The data obtained from unstimulated cells showed a significantly higher basal expression of PRMT1 and mitochondrial markers in asthmatic compared with control fibroblasts. In all cells, TGF-ß significantly increased the expression of PRMT1 through SMAD2/3 and C/EBPß. Subsequently, PRMT1 upregulated the expression of the mitochondria regulators PGC-1α and heat shock protein 60. Both the inhibition of the SAMD2/3 pathway or PRMT1 attenuated TGF-ß-induced mitochondrial mass and C/EBPß and α-SMA expression. These findings suggest that the signaling sequence controlling mitochondria in primary human lung fibroblasts is as follows: TGF-ß→SMAD2/3→C/EBPß→PRMT1→PGC-1α. Therefore, PRMT1 and C/EBPß present a novel therapeutic and diagnostic target for airway wall remodeling in chronic lung diseases.

Elevated IL-22 in psoriasis plays an anti-apoptotic role in keratinocytes through mediating Bcl-xL/Bax.

IL-22 is known to mediate inflammation in psoriasis, while IL-22 binding protein (IL-22BP) binds IL-22 to suppress IL-22 signaling. However, the function of IL-22 in regulating apoptosis in psoriasis remains poorly understood. In this study, we found that IL-22/IL-22R1 in lesional skin and IL-22 in serum from psoriatic patients were highly upregulated compared with healthy controls, while IL-22BP was not changed. Correlations between IL-22/IL-22R1 levels and the thickness of psoriatic lesions suggested that IL-22 might positively regulate abnormal hyperplasia in psoriasis. Apoptotic keratinocytes were increased only in stratum corneum, but not in spinous and basal layers of psoriasis. Moreover, IL-22 promoted cell viability in human epidermal keratinocytes (HEKs). The apoptosis induced by TNF-α and IFN-γ was inhibited in HEKs treated with IL-22, since that IL-22 upregulated Bcl-xL and downregulated Bax production in HEKs in the presence of TNF-α and IFN-γ. In addition, IL-22BP could counteract the anti-apoptotic effect of IL-22. Our finding demonstrates that IL-22 might play an anti-apoptosis role on keratinocytes to balance cell proliferation and apoptosis in psoriatic epidermis.

Up-regulated DERL3 in fibroblast-like synoviocytes exacerbates inflammation of rheumatoid arthritis.

Endoplasmic reticulum (ER) stress associated proteins contribute to the pathogenesis of rheumatoid arthritis (RA) through affecting synoviocyte proliferation and proinflammatory cytokine production. The role of DERL3, an ER-associated degradation component, in joint inflammation of RA was explored. Synovial tissues from RA and osteoarthritis (OA) patients were collected, and in RA synovial tissue, DERL3 showed up-regulation and significantly positive correlation with the expression of tumor necrosis factor alpha (TNF-α), interleukin (IL)-6 and matrix metalloproteinase (MMP)-1. Immunofluorescence result suggested DERL3 was located in fibroblast-like synoviocytes (FLS). Among different inflammatory stimuli, DERL3 could be up-regulated by TNF-α stimulation in FLS. Under TNF-α stimulation, knocking down DERL3, the expression of IL-6, IL-8, MMP-1, MMP-13 was reduced and the activation of nuclear factor kappa B (NF-κB) signaling pathway was inhibited. In pristane-induced arthritis (PIA) rat model, Derl3 was up-regulated in synovial tissue and disease was attenuated after intraarticular injection of siDerl3. Overall, we conclude that TNF-α inducing DERL3 expression promotes the inflammation of FLS through activation of NF-κB signaling pathway, suggesting DERL3 plays important roles in the pathogenesis of RA and is a promising therapeutic target.

W941, a new PI3K inhibitor, exhibits preferable anti-proliferative activities against nonsmall cell lung cancer with autophagy inhibitors.

The PI3K pathway is aberrantly activated in many cancers and plays a critical role in tumour cell proliferation and survival, making it a rational therapeutic target. In the present study, the effects and the underlying mechanism of a new PI3K inhibitor, W941, were investigated in non-small-cell lung cancer (NSCLC). The results of this study showed that W941 inhibited the growth of A549 and Hcc827 cells with IC50 values of 0.12 and 0.23 µM, respectively, and that W941 markedly inhibited the growth of A549 xenograft tumours in a nude mouse model without decreasing body weight. Western blotting assays showed that W941 inhibited the phosphorylation of downstream proteins in the PI3K pathway (AKT, mTOR, p70S6K and 4EBP1) in both A549 and Hcc827 cells. In addition, after W941 treatment, a dose-dependent increase in the ratio of the LC3-II/I ratio was observed. When cells were pre-treated with chloroquine or bafilomycin A1, W941 increased the LC3-II/I ratio, suggesting that W941 acted as an autophagy inducer. Moreover, autophagy blockers enhanced apoptosis after W941 treatment, indicating that W941-induced autophagy actually protected the cells against its cytotoxicity. Our findings suggest that the combination of a PI3K inhibitor with an autophagy inhibitor might be a novel option for NSCLC treatment.