Spatial CRISPR genomics identifies regulators of the tumor microenvironment.

While CRISPR screens are helping uncover genes regulating many cell-intrinsic processes, existing approaches are suboptimal for identifying extracellular gene functions, particularly in the tissue context. Here, we developed an approach for spatial functional genomics called Perturb-map. We applied Perturb-map to knock out dozens of genes in parallel in a mouse model of lung cancer and simultaneously assessed how each knockout influenced tumor growth, histopathology, and immune composition. Moreover, we paired Perturb-map and spatial transcriptomics for unbiased analysis of CRISPR-edited tumors. We found that in Tgfbr2 knockout tumors, the tumor microenvironment (TME) was converted to a fibro-mucinous state, and T cells excluded, concomitant with upregulated TGFß and TGFß-mediated fibroblast activation, indicating that TGFß-receptor loss on cancer cells increased TGFß bioavailability and its immunosuppressive effects on the TME. These studies establish Perturb-map for functional genomics within the tissue at single-cell resolution with spatial architecture preserved and provide insight into how TGFß responsiveness of cancer cells can affect the TME.

The expression of SOCS1 is regulated by promoter DNA methylation and is associated with mitochondria-mediated apoptosis of T-2 induced chondrocytes.

At present, the function of SOCS1 in Kashin-Beck disease (KBD) has not been reported. This study aims to explore the expression and mechanism of SOCS1 in KBD, and provide theoretical basis for the prevention and treatment of KBD. The expression of SOCS1 were measured by qRT-PCR and Western blot. ELISA was used to detect the content of SOCS1 in serum and synovial fluid. CCK-8 kits were selected to measure the cell viability. Methylation Specific PCR (MSP) assay is used to detect the methylation level of SOCS1 in chondrocytes. Flow cytometry was used to analyze the apoptosis rate of chondrocytes in different groups. The expression of apoptosis related proteins (caspase-3 and caspase-9) and Cytochrome c were detected using Western blot. The mitochondrial ROS, ATP and the activity of mitochondrial respiratory chain complexes were detected using commercial kits. The results showed that the expression of SOCS1 significantly increases in KBD patients and T-2 induced chondrocytes. Further research has found that the methylation levels of SOCS1 were significantly reduced in KBD patients and T-2 induced chondrocytes. Functional studies have found that SOCS1 silencing inhibited chondrocyte apoptosis and mitochondrial dysfunction. More importantly, SOCS1 regulated mitochondrial mediated chondrocyte apoptosis through the IGF-1/IGF-1R/FAK/Drp1 pathway. In conclusion, SOCS1 expression is increased and methylation levels are decreased in KBD, and is involved in regulating mitochondrial mediated apoptosis in T-2 induced chondrocytes through IGF-1/IGF-1R/FAK/Drp1 signaling. This study provides new theoretical basis for the treatment and prevention of KBD in clinical practice.

Downregulation of lncRNA CDKN2B-AS1 attenuates inflammatory response in mice with allergic rhinitis by regulating miR-98-5p/SOCS1 axis.

Long non-coding RNA cyclin-dependent kinase inhibitor 2B antisense RNA 1 (CDKN2B-AS1) in various diseases has been verified. However, the underlying mechanism of CDKN2B-AS1 contributes to the development of allergic rhinitis (AR) remains unknown. To evaluate the impact of CDKN2B-AS1 on AR, BALB/c mice were sensitized by intraperitoneal injection of normal saline containing ovalbumin (OVA) and calmogastrin to establish an AR model. Nasal rubbing and sneezing were documented after the final OVA treatment. The concentrations of IgE, IgG1, and inflammatory elements were quantified using ELISA. Hematoxylin and eosin (H&E) staining and immunofluorescence were used to assess histopathological variations and tryptase expression, respectively. StarBase, TargetScan and luciferase reporter assays were applied to predict and confirm the interactions among CDKN2B-AS1, miR-98-5p, and SOCS1. CDKN2B-AS1, miR-98-5p, and SOCS1 levels were assessed by quantitative real-time PCR (qRT-PCR) or western blotting. Our results revealed that CDKN2B-AS1 was obviously over-expressed in the nasal mucosa of AR patients and AR mice. Down-regulation of CDKN2B-AS1 significantly decreased nasal rubbing and sneezing frequencies, IgE and IgG1 concentrations, and cytokine levels. Furthermore, down-regulation of CDKN2B-AS1 also relieved the pathological changes in the nasal mucosa, and the infiltration of eosinophils and mast cells. Importantly, these results were reversed by the miR-98-5p inhibitor, whereas miR-98-5p directly targeted CDKN2B-AS1, and miR-98-5p negatively regulated SOCS1 level. Our findings demonstrate that down-regulation of CDKN2B-AS1 improves allergic inflammation and symptoms in a murine model of AR through the miR-98-5p/SOCS1 axis, which provides new insights into the latent functions of CDKN2B-AS1 in AR treatment.

RNF123 Mediates Ubiquitination and Degradation of SOCS1 To Regulate Type I Interferon Production during Duck Tembusu Virus Infection.

Many RING domain E3 ubiquitin ligases play critical roles in fine-tuning the innate immune response, yet little is known about their regulatory role in flavivirus-induced innate immunity. In previous studies, we found that the suppressor of cytokine signaling 1 (SOCS1) protein mainly undergoes lysine 48 (K48)-linked ubiquitination. However, the E3 ubiquitin ligase that promotes the K48-linked ubiquitination of SOCS1 is unknown. In the present study, we found that RING finger protein 123 (RNF123) binds to the SH2 domain of SOCS1 through its RING domain and facilitates the K48-linked ubiquitination of the K114 and K137 residues of SOCS1. Further studies found that RNF123 promoted the proteasomal degradation of SOCS1 and promoted Toll-like receptor 3 (TLR3)- and interferon (IFN) regulatory factor 7 (IRF7)-mediated type I IFN production during duck Tembusu virus (DTMUV) infection through SOCS1, ultimately inhibiting DTMUV replication. Overall, these findings demonstrate a novel mechanism by which RNF123 regulates type I IFN signaling during DTMUV infection by targeting SOCS1 degradation. IMPORTANCE In recent years, posttranslational modification (PTM) has gradually become a research hot spot in the field of innate immunity regulation, and ubiquitination is one of the critical PTMs. DTMUV has seriously endangered the development of the waterfowl industry in Southeast Asian countries since its outbreak in 2009. Previous studies have shown that SOCS1 is modified by K48-linked ubiquitination during DTMUV infection, but E3 ubiquitin ligase catalyzing the ubiquitination of SOCS1 has not been reported. Here, we identify for the first time that RNF123 acts as an E3 ubiquitin ligase that regulates TLR3- and IRF7-induced type I IFN signaling during DTMUV infection by targeting the K48-linked ubiquitination of the K114 and K137 residues of SOCS1 and the proteasomal degradation of SOCS1.

Long Noncoding RNA Metastasis-Associated Lung Adenocarcinoma Transcript 1 Promotes HIV-1 Replication through Modulating microRNAs in Macrophages.

Macrophages can serve as a reservoir for human immunodeficiency-1 (HIV-1) virus in host cells, constituting a barrier to eradication, even in patients who are receiving antiretroviral therapy. Although many noncoding RNAs have been characterized as regulators in HIV-1/AIDS-induced immune response and pathogenesis, only a few long noncoding RNAs (lncRNAs) have demonstrated a close association with HIV-1 replication, and the molecular mechanisms remain unknown. In this study, we investigated how lncRNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), related microRNAs, and key inflammatory genes alter HIV-1 replication in macrophages. Our data show that HIV-1 infection modulates the expression of miR-155 and miR-150-5p in a time-dependent manner, which is regulated by MALAT1. MALAT1 induced suppressor of cytokine signaling 1 (SOCS1) expression by sponging miR-150-5p in HIV-1-infected macrophages and stimulated inflammatory mediators triggering receptor expressed on myeloid cells/cold inducible RNA binding protein (TREM 1/CIRP) ligand/receptor. The RNA immunoprecipitation (RIP) assay validated the direct interaction within the MALAT1/miR-150-5p/SOCS1 axis. HIV-1 infection-mediated upregulation of MALAT1, SOCS1, and HIV-1 Gag was attenuated by SN50 (an NF-кB p50 inhibitor). MALAT1 antisense oligonucleotides (ASOs) suppressed HIV-1 p24 production and HIV-1 Gag gene expression and decreased expression of miR-155 and SOCS1, as well as the production of proinflammatory cytokines by HIV-1-infected macrophages. In conclusion, HIV-1 infection induces MALAT1, which attenuates miR-150-5p expression and increases SOCS1 expression, promoting HIV-1 replication and reactivation. These data provide new insights into how MALAT1 alters the macrophage microenvironment and subsequently promotes viral replication and suggest a potential role for targeting MALAT1 as a therapeutic approach to eliminate HIV-1 reservoirs. IMPORTANCE Viral reservoirs constitute an obstacle to curing HIV-1 diseases, despite antiretroviral therapy. Macrophages serve as viral reservoirs in HIV infection by promoting long-term replication and latency. Recent studies have shown that lncRNAs can modulate virus-host interactions, but the underlying mechanisms are not fully understood. In this study, we demonstrate how lncRNA MALAT1 contributes to HIV-1 replication through modulation of the miR-150/SOCS1 axis in human macrophages. Our findings have the potential to identify new therapies for eliminating HIV-1 reservoirs in immune cells.

EP300 improves endothelial injury and mitochondrial dysfunction in coronary artery disease by regulating histone acetylation of SOCS1 promoter via inhibiting JAK/STAT pathway.

Endothelial cell injury and mitochondrial dysfunction are crucial events during coronary artery disease (CAD). Suppressor of cytokine signaling-1 (SOCS1) is a negative mediator for inflammation, but there are few reports regarding histone acetylation of SOCS1 in CAD. The aim of the current study is to examine the impact of SOCS1 in CAD patients and human umbilical vein endothelial cells (HUVECs). We enrolled patients with CAD and healthy volunteers. HUVECs treated with ox-LDL were used as in vitro model. This study showed that SOCS1 expression was decreased in patients with CAD and ox-LDL-stimulated HUVECs. Overexpressing SOCS1 ameliorated endothelial cell injury and mitochondrial dysfunction induced by ox-LDL in vitro. Moreover, EP300 promoted SOCS1 transcription through increasing the acetylation of SOCS1 and recruiting H3K27ac to the SOCS1 gene promoter in HUVECs induced by ox-LDL. Additionally, SOCS1 repressed JAK/STAT cascade in ox-LDL-stimulated HUVECs. Silencing of EP300 reversed endothelial cell injury and mitochondrial dysfunction ameliorated by overexpression of SOCS1 in ox-LDL-induced HUVECs. In summary, SOCS1 alleviated endothelial injury and mitochondrial dysfunction via enhancing H3K27ac acetylation by recruiting EP300 to promoter region and inhibiting JAK/STAT pathway. These results contribute to discover underlying diagnostic biomarkers and therapeutic targets for CAD.

Targeted silencing of SOCS1 by DNMT1 promotes stemness of human liver cancer stem-like cells.

BACKGROUND: Human liver cancer stem-like cells (HLCSLCs) are widely acknowledged as significant factors in the recurrence and eradication of hepatocellular carcinoma (HCC). The sustenance of HLCSLCs' stemness is hypothesized to be intricately linked to the epigenetic process of DNA methylation modification of genes associated with anticancer properties. The present study aimed to elucidate the stemness-maintaining mechanism of HLCSLCs and provide a novel idea for the clearance of HLCSLCs. METHODS: The clinical relevance of DNMT1 and SOCS1 in hepatocellular carcinoma (HCC) patients was evaluated through the GEO and TCGA databases. Cellular immunofluorescence assay, methylation-specific PCR, chromatin immunoprecipitation were conducted to explore the expression of DNMT1 and SOCS1 and the regulatory relationship between them in HLCSLCs. Spheroid formation, soft agar colony formation, expression of stemness-associated molecules, and tumorigenicity of xenograft in nude mice were used to evaluate the stemness of HLCSLCs. RESULTS: The current analysis revealed a significant upregulation of DNMT1 and downregulation of SOCS1 in HCC tumor tissues compared to adjacent normal liver tissues. Furthermore, patients exhibiting an elevated DNMT1 expression or a reduced SOCS1 expression had low survival. This study illustrated the pronounced expression and activity of DNMT1 in HLCSLCs, which effectively targeted the promoter region of SOCS1 and induced hypermethylation, consequently suppressing the expression of SOCS1. Notably, the stemness of HLCSLCs was reduced upon treatment with DNMT1 inhibitors in a concentration-dependent manner. Additionally, the overexpression of SOCS1 in HLCSLCs significantly mitigated their stemness. The knockdown of SOCS1 expression reversed the effect of DNMT1 inhibitor on the stemness of HLCSLCs. DNMT1 directly binds to the SOCS1 promoter. In vivo, DNMT1 inhibitors suppressed SOCS1 expression and inhibited the growth of xenograft. CONCLUSION: DNMT1 targets the promoter region of SOCS1, induces hypermethylation of its CpG islands, and silences its expression, thereby promoting the stemness of HLCSLCs.

Tumor-derived miR-6794-5p enhances cancer growth by promoting M2 macrophage polarization.

BACKGROUND: Solid tumors promote tumor malignancy through interaction with the tumor microenvironment, resulting in difficulties in tumor treatment. Therefore, it is necessary to understand the communication between cells in the tumor and the surrounding microenvironment. Our previous study revealed the cancer malignancy mechanism of Bcl-w overexpressed in solid tumors, but no study was conducted on its relationship with immune cells in the tumor microenvironment. In this study, we sought to discover key factors in exosomes secreted from tumors overexpressing Bcl-w and analyze the interaction with the surrounding tumor microenvironment to identify the causes of tumor malignancy. METHODS: To analyze factors affecting the tumor microenvironment, a miRNA array was performed using exosomes derived from cancer cells overexpressing Bcl-w. The discovered miRNA, miR-6794-5p, was overexpressed and the tumorigenicity mechanism was confirmed using qRT-PCR, Western blot, invasion, wound healing, and sphere formation ability analysis. In addition, luciferase activity and Ago2-RNA immunoprecipitation assays were used to study the mechanism between miR-6794-5p and its target gene SOCS1. To confirm the interaction between macrophages and tumor-derived miR-6794-5p, co-culture was performed using conditioned media. Additionally, immunohistochemical (IHC) staining and flow cytometry were performed to analyze macrophages in the tumor tissues of experimental animals. RESULTS: MiR-6794-5p, which is highly expressed in exosomes secreted from Bcl-w-overexpressing cells, was selected, and it was shown that the overexpression of miR-6794-5p increased migratory ability, invasiveness, and stemness maintenance by suppressing the expression of the tumor suppressor SOCS1. Additionally, tumor-derived miR-6794-5p was delivered to THP-1-derived macrophages and induced M2 polarization by activating the JAK1/STAT3 pathway. Moreover, IL-10 secreted from M2 macrophages increased tumorigenicity by creating an immunosuppressive environment. The in vitro results were reconfirmed by confirming an increase in M2 macrophages and a decrease in M1 macrophages and CD8+ T cells when overexpressing miR-6794-5p in an animal model. CONCLUSIONS: In this study, we identified changes in the tumor microenvironment caused by miR-6794-5p. Our study indicates that tumor-derived miR-6794-5p promotes tumor aggressiveness by inducing an immunosuppressive environment through interaction with macrophage.

The Role of JAK-STAT-SOCS1 Axis in Tumorigenesis, Malignant Progression and Lymphatic Metastasis of Penile Cancer.

Background: To uncover the potential significance of JAK-STAT-SOCS1 axis in penile cancer, our study was the pioneer in exploring the altered expression processes of JAK-STAT-SOCS1 axis in tumorigenesis, malignant progression and lymphatic metastasis of penile cancer. Methods: In current study, the comprehensive analysis of JAK-STAT-SOCS1 axis in penile cancer was analyzed via multiple analysis approaches based on GSE196978 data, single-cell data (6 cancer samples) and bulk RNA data (7 cancer samples and 7 metastasis lymph nodes). Results: Our study observed an altered molecular expression of JAK-STAT-SOCS1 axis during three different stages of penile cancer, from tumorigenesis to malignant progression to lymphatic metastasis. STAT4 was an important dominant molecule in penile cancer, which mediated the immunosuppressive tumor microenvironment by driving the apoptosis of cytotoxic T cell and was also a valuable biomarker of immune checkpoint inhibitor treatment response. Conclusions: Our findings revealed that the complexity of JAK-STAT-SOCS1 axis and the predominant role of STAT4 in penile cancer, which can mediate tumorigenesis, malignant progression, and lymphatic metastasis. This insight provided valuable information for developing precise treatment strategies for patients with penile cancer.

TRIM8 Promotes Proliferation, Invasion, and Migration of Cervical Cancer Cells by Ubiquitinating and Degrading SOCS1.

Cervical cancer (CC) is a malignant tumor primarily caused by the persistent infection with high-risk strains of human papillomavirus. This study investigates the aberrant expression of Tripartite Motif Containing 8 (TRIM8) in CC and its impact on cell proliferation, invasion, and migration. Expression levels of TRIM8, Proliferating Cell Nuclear Antigen, and Suppressor of Cytokine Signaling 1 (SOCS1) were assessed in CC cell lines. CC cells were transfected with si-TRIM8, followed by cell counting kit-8 (CCK-8) assay, colony formation assay, and Transwell assay. Protein immunoprecipitation assay was employed to examine TRIM8's binding with SOCS1, and the ubiquitination level of SOCS1 was determined after MG132 treatment. Rescue experiments were conducted using si-SOCS1 and si-TRIM8 in combination. Results indicate upregulation of TRIM8 in CC cells. Inhibition of TRIM8 suppressed cell viability, proliferation, invasion, and migration. TRIM8 promoted CC cell proliferation, invasion, and migration of CC cells through ubiquitination-mediated degradation of SOCS1. Inhibition of SOCS1 partially reversed the inhibitory effects of si-TRIM8 on the proliferation, invasion, and migration of CC cells. In conclusion, TRIM8 enhances CC cell proliferation, invasion, and migration via ubiquitination-mediated degradation of SOCS1.

Annona squamosa Fruit Extract Ameliorates Lead Acetate-Induced Testicular Injury by Modulating JAK-1/STAT-3/SOCS-1 Signaling in Male Rats.

Lead (Pb) is a common pollutant that is not biodegradable and gravely endangers the environment and human health. Annona squamosa fruit has a wide range of medicinal uses owing to its phytochemical constituents. This study evaluated the effect of treatment with A. squamosa fruit extract (ASFE) on testicular toxicity induced in male rats by lead acetate. The metal-chelating capacity and phytochemical composition of ASFE were determined. The LD50 of ASFE was evaluated by probit analysis. Molecular docking simulations were performed using Auto Dock Vina. Forty male Sprague Dawley rats were equally divided into the following groups: Gp1, a negative control group; Gp2, given ASFE (350 mg/kg body weight (b. wt.)) (1/10 of LD50); Gp3, given lead acetate (PbAc) solution (100 mg/kg b. wt.); and Gp4, given PbAc as in Gp3 and ASFE as in Gp2. All treatments were given by oro-gastric intubation daily for 30 days. Body weight changes, spermatological parameters, reproductive hormone levels, oxidative stress parameters, and inflammatory biomarkers were evaluated, and molecular and histopathological investigations were performed. The results showed that ASFE had promising metal-chelating activity and phytochemical composition. The LD50 of ASFE was 3500 mg/kg b. wt. The docking analysis showed that quercetin demonstrated a high binding affinity for JAK-1 and STAT-3 proteins, and this could make it a more promising candidate for targeting the JAK-1/STAT-3 pathway than others. The rats given lead acetate had defective testicular tissues, with altered molecular, biochemical, and histological features, as well as impaired spermatological characteristics. Treatment with ASFE led to a significant mitigation of these dysfunctions and modulated the JAK-1/STAT-3/SOCS-1 axis in the rats.

Identification and validation of SOCS1/2/3/4 as potential prognostic biomarkers and correlate with immune infiltration in glioblastoma.

Suppressor of cytokine signalling (SOCS) 1/2/3/4 are involved in the occurrence and progression of multiple malignancies; however, their prognostic and developmental value in patients with glioblastoma (GBM) remains unclear. The present study used TCGA, ONCOMINE, SangerBox3.0, UALCAN, TIMER2.0, GENEMANIA, TISDB, The Human Protein Atlas (HPA) and other databases to analyse the expression profile, clinical value and prognosis of SOCS1/2/3/4 in GBM, and to explore the potential development mechanism of action of SOCS1/2/3/4 in GBM. The majority of analyses showed that SOCS1/2/3/4 transcription and translation levels in GBM tissues were significantly higher than those in normal tissues. qRT-PCR, western blotting (WB) and immunohistochemical staining were used to verify that SOCS3 was expressed at higher mRNA and protein levels in GBM than in normal tissues or cells. High SOCS1/2/3/4 mRNA expression was associated with poor prognosis in patients with GBM, especially SOCS3. SOCS1/2/3/4 were highly contraindicated, which had few mutations, and were not associated with clinical prognosis. Furthermore, SOCS1/2/3/4 were associated with the infiltration of specific immune cell types. In addition, SOCS3 may affect the prognosis of patients with GBM through JAK/STAT signalling pathway. Analysis of the GBM-specific protein interaction (PPI) network showed that SOCS1/2/3/4 were involved in multiple potential carcinogenic mechanisms of GBM. In addition, colony formation, Transwell, wound healing and western blotting assays revealed that inhibition of SOCS3 decreased the proliferation, migration and invasion of GBM cells. In conclusion, the present study elucidated the expression profile and prognostic value of SOCS1/2/3/4 in GBM, which may provide potential prognostic biomarkers and therapeutic targets for GBM, especially SOCS3.

SOCS1 as a Biomarker Candidate for HPV Infection and Prognosis of Head and Neck Squamous Cell Carcinomas.

The pathogenesis of head and neck squamous cell carcinoma (HNSCC) is associated with human papillomavirus (HPV) infection. However, the molecular mechanisms underlying the interactions between HNSCC and HPV remain unclear. Bioinformatics was used to analyze the gene expression dataset of HPV-associated HNSCC based on the Cancer Genome Atlas (TCGA) database. Differentially expressed genes (DEGs) in HPV-positive and HPV-negative HNSCC were screened. Gene function enrichment, protein-protein interactions (PPI), survival analysis, and immune cell infiltration of DEGs were performed. Furthermore, the clinical data of HNSCC tissue samples were analyzed using immunohistochemistry. In total, 194 DEGs were identified. A PPI network was constructed and 10 hub genes (EREG, PLCG1, ERBB4, HBEGF, ZFP42, CBX6, NFKBIA, SOCS1, ATP2B2, and CEND1) were identified. Survival analysis indicated that low expression of SOCS1 was associated with worse overall survival. Immunohistochemistry demonstrated that SOCS1 expression was higher in HPV-negative HNSCC than in HPV-positive HNSCC, and there was a positive correlation between SOCS1 expression and patient survival. This study provides new information on biological targets that may be relevant to the molecular mechanisms underpinning the occurrence and development of HNSCC. SOCS1 may play an important role in the interaction between HPV and HNSCC and serve as a potential biomarker for future therapeutic targets.

Insights into the expanding intestinal phenotypic spectrum of SOCS1 haploinsufficiency and therapeutic options.

PURPOSE: Hyper activation of the JAK-STAT signaling underlies the pathophysiology of many human immune-mediated diseases. Herein, the study of 2 adult patients with SOCS1 haploinsufficiency illustrates the severe and pleomorphic consequences of its impaired regulation in the intestinal tract. METHODS: Two unrelated adult patients presented with gastrointestinal manifestations, one with Crohn's disease-like ileo-colic inflammation refractory to anti-TNF and the other with lymphocytic leiomyositis causing severe chronic intestinal pseudo-occlusion. Next-generation sequencing was used to identify the underlying monogenic defect. One patient received anti-IL-12/IL-23 treatment while the other received the JAK1 inhibitor, ruxolitinib. Peripheral blood, intestinal tissues, and serum samples were analyzed before-and-after JAK1 inhibitor therapy using mass cytometry, histology, transcriptomic, and Olink assay. RESULTS: Novel germline loss-of-function variants in SOCS1 were identified in both patients. The patient with Crohn-like disease achieved clinical remission with anti-IL-12/IL-23 treatment. In the second patient with lymphocytic leiomyositis, ruxolitinib induced rapid resolution of the obstructive symptoms, significant decrease of the CD8+ T lymphocyte muscular infiltrate, and normalization of serum and intestinal cytokines. Decreased frequencies of circulating Treg cells, MAIT cells, and NK cells, with altered CD56bright:CD16lo:CD16hi NK subtype ratios were not modified by ruxolitinib. CONCLUSION: SOCS1 haploinsufficiency can result in a broad spectrum of intestinal manifestations and need to be considered as differential diagnosis in cases of severe treatment-refractory enteropathies, including the rare condition of lymphocytic leiomyositis. This provides the rationale for genetic screening and considering JAK inhibitors in such cases.

IL4Rα and IL17A Blockade Rescue Autoinflammation in SOCS1 Haploinsufficiency.

By inhibition of JAK-STAT signaling, SOCS1 acts as a master regulator of the cytokine response across numerous tissue types and cytokine pathways. Haploinsufficiency of SOCS1 has recently emerged as a monogenic immunodysregulatory disease with marked clinical variability. Here, we describe a patient with severe dermatitis, recurrent skin infections, and psoriatic arthritis that harbors a novel heterozygous mutation in SOCS1. The variant, c.202_203delAC, generates a frameshift in SOCS1, p.Thr68fsAla*49, which leads to complete loss of protein expression. Unlike WT SOCS1, Thr68fs SOCS1 fails to inhibit JAK-STAT signaling when expressed in vitro. The peripheral immune signature from this patient was marked by a redistribution of monocyte sub-populations and hyper-responsiveness to multiple cytokines. Despite this broad hyper-response across multiple cytokine pathways in SOCS1 haploinsufficiency, the patient's clinical disease was markedly responsive to targeted IL4Rα- and IL17-blocking therapy. In accordance, the mutant allele was unable to regulate IL4Rα signaling. Further, patient cells were unresponsive to IL4/IL13 while on monoclonal antibody therapy. Together, this study reports a novel SOCS1 mutation and suggests that IL4Rα blockade may serve as an unexpected, but fruitful therapeutic target for some patients with SOCS1 haploinsufficiency.

Duck Tembusu Virus Inhibits Type I Interferon Production through the JOSD1-SOCS1-IRF7 Negative-Feedback Regulation Pathway.

Duck Tembusu virus (DTMUV) is an emerging pathogenic flavivirus that mainly causes a decrease in egg production in infected waterfowl. Similar to other members of the Flaviviridae family, it can proliferate in most mammalian cells and may also pose a potential threat to nonavian animals. In previous studies, we found that DTMUV infection can upregulate suppressor of cytokine signaling 1 (SOCS1) to inhibit type I interferon (IFN) production and promote virus replication, but the specific mechanism is unclear. Furthermore, little is known about the regulatory role of ubiquitination during flavivirus infection. In this study, we found that activation of Toll-like receptor 3 (TLR3) signaling rather than type I IFN stimulation led to the upregulation of SOCS1 during DTMUV infection. Further studies revealed that JOSD1 stabilized SOCS1 expression by binding to the SH2 domain of SOCS1 and mediating its deubiquitination. In addition, JOSD1 also inhibited type I IFN production through SOCS1. Finally, SOCS1 acts as an E3 ubiquitin ligase that binds to IFN regulatory factor 7 (IRF7) through its SH2 domain and mediates K48-linked ubiquitination and proteasomal degradation of IRF7, ultimately inhibiting type I IFN production mediated by IRF7 and promoting viral proliferation. These results will enrich and deepen our understanding of the mechanism by which DTMUV antagonizes the host interferon system. IMPORTANCE DTMUV is a newly discovered flavivirus that seriously harms the poultry industry. In recent years, there have been numerous studies on the involvement of ubiquitination in the regulation of innate immunity. However, little is known about the involvement of ubiquitination in the regulation of flavivirus-induced type I IFN signaling. In this study, we found that SOCS1 was induced by TLR3 signaling during DTMUV infection. Furthermore, we found for the first time that duck SOCS1 protein was also modified by K48-linked polyubiquitination, whereas our previous study found that SOCS1 was upregulated during DTMUV infection. Further studies showed that JOSD1 stabilized SOCS1 expression by mediating the deubiquitination of SOCS1. While SOCS1 acts as a negative regulator of cytokines, we found that DTMUV utilized SOCS1 to mediate the ubiquitination and proteasomal degradation of IRF7 and ultimately inhibit type I IFN production, thereby promoting its proliferation.

In cis "benign" SOCS1 variants linked to enhanced interferon signaling and autoimmunity.

We aimed to characterize the genetic basis of disease in a family with multiple autoimmune manifestations, including systemic lupus erythematosus (SLE), immune thrombocytopenia, and autoimmune thyroiditis. Whole exome sequencing (WES) was conducted to identify candidate variants, which were analyzed by flow cytometry, immunoblotting, immunoprecipitation, and luciferase reporter assay in transfected 293T cells. Gene expression in peripheral blood mononuclear cells (PBMC) was profiled by bulk RNA sequencing and plasma cytokines were measured by proximity extension assay. In two siblings with early-onset SLE and immune thrombocytopenia, WES identified two maternally inherited in cis variants (p. Pro50Leu and p.Ala76Gly) in Suppressor of cytokine signaling 1 (SOCS1), flanking the kinase inhibitory domain that interacts with Janus kinases (JAK). Both variants were predicted to be benign by most in silico algorithms and neither alone affected the ability of SOCS1 to inhibit JAK-STAT1 signaling by functional studies. When both variants were expressed in cis, the mutant SOCS1 protein displayed decreased binding to JAK1 and reduced capacity to inhibit type I interferon (IFN-I) signaling by ∼20-30% compared to the wildtype protein. PBMC from the probands and their mother showed increased expression of interferon-inducible genes compared to healthy controls, supporting defective regulation of IFN-I signaling. Cells from all three subjects displayed heightened sensitivity to IFN-I stimulation, while response to IFN-γ, IL-4, and IL-6 was comparable to healthy controls. Our work illustrates the critical fine-tuning of IFN-I signaling by SOCS1 to prevent autoimmunity. We show that a combination of genetic variants that are individually benign may have deleterious consequences.

The SOCS1 KIR and SH2 domain are both required for suppression of cytokine signaling in vivo.

Suppressor Of Cytokine Signaling (SOCS) 1 is a critical negative regulator of cytokine signaling and required to protect against an excessive inflammatory response. Genetic deletion of Socs1 results in unrestrained cytokine signaling and neonatal lethality, characterised by an inflammatory immune infiltrate in multiple organs. Overexpression and structural studies have suggested that the SOCS1 kinase inhibitory region (KIR) and Src homology 2 (SH2) domain are important for interaction with and inhibition of the receptor-associated JAK1, JAK2 and TYK2 tyrosine kinases, which initiate downstream signaling. To investigate the role of the KIR and SH2 domain in SOCS1 function, we independently mutated key conserved residues in each domain and analysed the impact on cytokine signaling, and the in vivo impact on SOCS1 function. Mutation of the SOCS1-KIR or SH2 domain had no impact on the integrity of the SOCS box complex, however, mutation within the phosphotyrosine binding pocket of the SOCS1-SH2 domain specifically disrupted SOCS1 interaction with phosphorylated JAK1. In contrast, mutation of the KIR did not affect the interaction with JAK1, but did prevent SOCS1 inhibition of JAK1 autophosphorylation. In human and mouse cell lines, both mutants impacted the ability of SOCS1 to restrain cytokine signaling, and crucially, Socs1-R105A and Socs1-F59A mice displayed a neonatal lethality and excessive inflammatory phenotype similar to Socs1-null mice. This study defines a critical and non-redundant role for both the KIR and SH2 domain in endogenous SOCS1 function.

LncRNA CASC9 enhances the stability of SOCS-1 by combining with FUS to alleviate sepsis-induced liver injury.

BACKGROUND: Liver injury plays a major role in the development of sepsis. Liver damage after sepsis is an independent risk factor for multiple organ failure and death. Cancer susceptibility candidate 9 (CASC9) exerts a protective effect on sepsis-induced acute lung injury (ALI). However, the role and underlying mechanism haven't been fully evaluated. METHODS: Animal and cell models of sepsis were established in vivo and in vitro experiments. The histological and apoptosis analyses of liver tissues were tested by hematoxylin-eosin (HE) staining and terminal dUTP nick end labeling (TUNEL) assay, respectively. Serum levels of inflammatory cytokines were detected via using an enzyme-linked immunosorbent assay (ELISA). The expressions of CASC9, suppressor of cytokine signaling (SOCS)-1, Bcl-2, Bax, Bad, and caspase3 were measured by reverse-transcription quantitative polymerase chain reaction (RT-qPCR) and western blotting. Cell counting kit-8 (CCK-8) and flow cytometry were applied to examine cell viability and apoptosis, respectively. RNA immunoprecipitation (RIP) and RNA-pull down assay were used to verify the binding relationships among CASC9, SOCS-1 and FUS. RESULTS: CASC9 and SOCS-1 were lowly expressed in animal and cell models of sepsis liver injury. CASC9 or SOCS-1 overexpression could inhibit cell apoptosis upon lipopolysaccharide (LPS) induction. Meanwhile, the serum levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-1ß, IL-6 and IL-8 were reduced by CASC9 or SOCS-1 overexpression in LPS-induced LO2 cells. Mechanistically, CASC9 interacted with fused in sarcoma (FUS) to stabilize the mRNA of SOCS-1. SOCS-1 silencing antagonized the effects of CASC9 on improving sepsis liver injury. CONCLUSION: CASC9 overexpression ameliorated the sepsis-induced liver injury, and the probable underlying mechanism may be that CASC9 stabilized the SOCS-1 mRNA by interacting with FUS.

B lymphocytes ameliorate Alzheimer's disease-like neuropathology via interleukin-35.

Increasing evidence supports the involvement of the peripheral immune system in the pathogenesis of Alzheimer's disease (AD). In the present study, we found that B lymphocytes could mitigate beta-Amyloid (Aß) pathology and memory impairments in a transgenic AD mouse model. Specifically, in young 5 × FAD mice, we evidenced increased B cells in the frontal cortex and meningeal tissues; depletion of mature B cells aggravated these mice's Aß load and memory deficits. The increased B cells produced more interleukin-35 (IL-35) in the front cortex. We further found IL-35 neutralization exacerbated Aß pathology, while injecting IL-35 mitigated Aß load and cognitive dysfunction in 5 × FAD mice with or without mature B cell deficiency. Mechanistically, IL-35 inhibited neuronal BACE1 transcription through modulating the SOCS1/STAT1 pathway, and reduced Aß production accordingly. Reanalysis of the single-cell RNA sequencing data from blood samples of AD patients suggested an increased population of IL-35-producing B cells. Together, the present study revealed a novel effect of B lymphocyte-derived IL-35 on inhibiting Aß production in the frontal cortex, which may serve as a potential target for future AD treatment.