Genetics of Neonatal Lupus Erythematosus Risk and Specific Manifestations.

OBJECTIVE: Neonatal lupus erythematosus (NLE) is a passively acquired autoimmune disease of infants born to anti-Ro and/or La autoantibody positive mothers. Genetics may impact NLE risk. We analyzed the genetics of infants and anti-Ro antibody positive mothers, with NLE and NLE specific manifestations. METHODS: Infants and mothers from a tertiary care clinic underwent genotyping on the Global Screening Array. We created additive non-HLA and HLA polygenic risk scores (PRSs) for systemic lupus erythematosus (SLE), from one of the largest genome wide association studies. Outcomes were any NLE manifestations, cardiac NLE, and cutaneous NLE. We tested the association between SLE-PRSs in the infant, mother, and the PRS difference between the mother and infant with NLE outcomes, in logistic regression and generalized linear mixed models (Bonferroni P<0.02). We also performed HLA-wide analyses for the outcomes (P<5.00x10-8). RESULTS: The study included 332 infants, 270 anti-Ro antibody positive mothers, and 253 mother-infant pairs. A large proportion of mothers (40.3%) and infants (41.3%) were European, and 50.0% of infants were female. More than half of the infants had NLE (53.0%), including 7.2% with cardiac NLE and 11.7% with cutaneous NLE. We did not identify significant associations between infant, maternal, or maternal-infant PRSs and any NLE outcomes. HLA-wide analyses did not identify NLE risk alleles. CONCLUSION: In a multiethnic cohort of infants and anti-Ro antibody positive mothers, we did not identify a significant association between SLE genetics and risk of NLE outcomes.

Characterization and functional analysis of chicken CDK protein.

The family of cell cycle-dependent kinases (CDKs) serves as catalytic subunits within protein kinase complexes, playing a crucial role in cell cycle progression. While the function of CDK proteins in regulating mammalian innate immune responses and virus replication is well-documented, their role in chickens remains unclear. To address this, we cloned several chicken CDKs, specifically CDK6 through CDK10. We observed that CDK6 is widely expressed across various chicken tissues, with localization in the cytoplasm, nucleus, or both in DF-1 cells. In addition, we also found that multiple chicken CDKs negatively regulate IFN-ß signaling induced by chicken MAVS or chicken STING by targeting different steps. Moreover, during infection with infectious bursal disease virus (IBDV), various chicken CDKs, except CDK10, were recruited and co-localized with viral protein VP1. Interestingly, overexpression of CDK6 in chickens significantly enhanced IBDV replication. Conversely, knocking down CDK6 led to a marked increase in IFN-ß production, triggered by chMDA5. Furthermore, targeting endogenous CDK6 with RNA interference substantially reduced IBDV replication. These findings collectively suggest that chicken CDKs, particularly CDK6, act as suppressors of IFN-ß production and play a facilitative role in IBDV replication.

Enhanced pyroptosis induction with pore-forming gene delivery for osteosarcoma microenvironment reshaping.

Osteosarcoma is the most common malignant bone tumor without efficient management for improving 5-year event-free survival. Immunotherapy is also limited due to its highly immunosuppressive tumor microenvironment (TME). Pore-forming gasdermins (GSDMs)-mediated pyroptosis has gained increasing concern in reshaping TME, however, the expressions and relationships of GSDMs with osteosarcoma remain unclear. Herein, gasdermin E (GSDME) expression is found to be positively correlated with the prognosis and immune infiltration of osteosarcoma patients, and low GSDME expression was observed. A vector termed as LPAD contains abundant hydroxyl groups for hydrating layer formation was then prepared to deliver the GSDME gene to upregulate protein expression in osteosarcoma for efficient TME reshaping via enhanced pyroptosis induction. Atomistic molecular dynamics simulations analysis proved that the hydroxyl groups increased LPAD hydration abilities by enhancing coulombic interaction. The upregulated GSDME expression together with cleaved caspase-3 provided impressive pyroptosis induction. The pyroptosis further initiated proinflammatory cytokines release, increased immune cell infiltration, activated adaptive immune responses and create a favorable immunogenic hot TME. The study not only confirms the role of GSDME in the immune infiltration and prognosis of osteosarcoma, but also provides a promising strategy for the inhibition of osteosarcoma by pore-forming GSDME gene delivery induced enhanced pyroptosis to reshape the TME of osteosarcoma.

Temperature extremes nip invasive macrophyte Cabomba caroliniana A. Gray in the bud: potential geographic distributions and risk assessment based on future climate change and anthropogenic influences.

Cabomba caroliniana A. Gray, an ornamental submerged plant indigenous to tropical America, has been introduced to numerous countries in Europe, Asia, and Oceania, impacting native aquatic ecosystems. Given this species is a popular aquarium plant and widely traded, there is a high risk of introduction and invasion into other environments. In the current study the potential global geographic distribution of C. caroliniana was predicted under the effects of climate change and human influence in an optimised MaxEnt model. The model used rigorously screened occurrence records of C. caroliniana from hydro informatic datasets and 20 associated influencing factors. The findings indicate that temperature and human-mediated activities significantly influenced the distribution of C. caroliniana. At present, C. caroliniana covers an area of approximately 1531×104 km2 of appropriate habitat, especially in the south-eastern parts of South, central and North America, Southeast Asia, eastern Australia, and most of Europe. The suitable regions are anticipated to expand under future climate scenarios; however, the dynamics of the changes vary between different extents of climate change. For example, C. caroliniana is expected to expand to higher latitudes, following global temperature increases under SSP1-2.6 and SSP2-4.5 scenarios, however, intolerance to temperature extremes may mediate invasion at higher latitudes under future extreme climate scenarios, e.g., SSP5-8.5. Owing to the severe impacts its invasion causes, early warning and stringent border quarantine processes are required to guard against the introduction of C. caroliniana especially in the invasion hotspots such as, Peru, Italy, and South Korea.

Systematic profiling of Taxol resistance and sensitivity to tubulin missence mutations at molecular and cellular levels.

Taxol (paclitaxel) is the first approved microtubule-stabilizing agent (MSA) by binding stoichiometrically to tubulin, which is considered to be one of the most significant advances in first-line chemotherapy against diverse tumors. However, a large number of residue missence mutations harboring in the tubulin have been observed to cause acquired drug resistance, largely limiting the clinical application of Taxol and its analogs in chemotherapy. A systematic investigation of the intermolecular interactions between the Taxol and various tubulin mutants would help to establish a comprehensive picture of drug response to tubulin mutations in clinical treatment of cancer, and to design new MSA agents with high potency and selectivity to overcome drug resistance. In this study, we described an integration of in silico analysis and in vitro assay (iSiV) to profile Taxol against a panel of 149 clinically observed, cancer-associated missence mutations in ß-tubulin at molecular and cellular levels, aiming to a systematic understanding of molecular mechanism and biological implication underlying drug resistance and sensitivity conferring from tubulin mutations. It is revealed that the Taxol-resistant mutations can be classified into three types: (I) nonbonded interaction broken due to mutation, (II) steric hindrance caused by mutation, and (III) conformational change upon mutation. In addition, we identified three new Taxol-resistant mutations (C239Y, T274I, and R320P) that can largely reduce the binding affinity of Taxol to tubulin at molecular level, in which the T274I and R320P were observed to considerably impair the antitumor activity of Taxol at cellular level. Moreover, a novel drug-susceptible mutation (M363T) was also identified, which improves Taxol affinity by 2.6-fold and decreases Taxol antitumor EC50 values from 29.4 to 18.7 µM.

Isolation, genome analysis and comparison of a novel parainfluenza virus 5 from a Siberian tiger (Panthera tigris).

Paramyxoviruses are important pathogens affecting various animals, including mammals and humans. Parainfluenza virus 5 (PIV5)-a member of the family Paramyxoviridae-is a major threat to the health of mammals and humans. However, studies on terrestrial wild animals infected with PIV5 are scanty. In this study, we utilized reverse transcription PCR to detect PIV5 infection in the visceral organ tissues of a Siberian tiger (Panthera tigris ssp. altaica) with vomiting, diarrhea, and dyspnea before its death. A novel PIV5 (named SR strain) with a slowly progressive cytopathic effect was isolated in Vero cells and validated using a transmission electron microscope. Full-length sequencing and analysis revealed that the whole genome of the PIV5 SR strain contained 15,246 nucleotides (nt) and seven non-overlapping genes (3'-N-V/P-M-F-SH-HN-L-5') encoding eight proteins. Phylogenetic analysis of three PIV5 strains identified in the same zoo confirmed that PIV5 strains SR and ZJQ-221 shared the closest genetic relationship as they were clustered in the same branch, while the recently found Siberian tiger strain SZ2 kept a certain distance and formed a relatively unique branch. Furthermore, mutations of nt and amino acids (aa) between strains ZJQ-221, SR, and SZ2 were identified. In summary, we report the identification and genomic characterization of a novel PIV5 strain SR isolated in a Siberian tiger, which may help future research on interspecific transmission mechanisms.

The complete chloroplast genome sequence of an invasive plant, Tragopogon dubius Scopoli (asteraceae).

Tragopogon dubius Scopoli is native to Europe and western Asia and is considered an invasive plant in China. In this study, the complete chloroplast genome of T. dubius was obtained using high-throughput next-generation sequencing technology. The whole chloroplast genome was 153,017 bp long with a GC content of 38% and comprised 130 genes (86 protein-coding genes, 36 tRNA genes, and 8 rRNA genes). Phylogenetic analysis based on the concatenated chloroplast protein-coding sequences showed that T. dubius is most closely related to Tragopogon pratensis. This study provides valuable genetic data for further phylogenetic analysis and molecular identification of species in the genus Tragopogon.

Strategic Structural Control of Polyserotonin Nanoparticles and Their Application as pH-Responsive Nanomotors.

Serotonin-based nanomaterials have been positioned as promising contenders for constructing multifunctional biomedical nanoplatforms due to notable biocompatibility, advantageous charge properties, and chemical adaptability. The elaborately designed structure and morphology are significant for their applications as functional carriers. In this study, we fabricated anisotropic bowl-like mesoporous polyserotonin (PST) nanoparticles with a diameter of approximately 170 nm through nano-emulsion polymerization, employing P123/F127 as a dual-soft template and 1,3,5-trimethylbenzene (TMB) as both pore expander and emulsion template. Their formation can be attributed to the synchronized assembly of P123/F127/TMB, along with the concurrent manifestation of anisotropic nucleation and growth on the TMB emulsion droplet surface. Meanwhile, the morphology of PST nanoparticles can be regulated from sphere- to bowl-like, with a particle size distribution ranging from 432 nm to 100 nm, experiencing a transformation from a dendritic, cylindrical open mesoporous structure to an approximately non-porous structure by altering the reaction parameters. The well-defined mesopores, intrinsic asymmetry, and pH-dependent charge reversal characteristics enable the as-prepared mesoporous bowl-like PST nanoparticles' potential for constructing responsive biomedical nanomotors through incorporating some catalytic functional materials, 3.5 nm CeO2 nanoenzymes, as a demonstration. The constructed nanomotors demonstrate remarkable autonomous movement capabilities under physiological H2O2 concentrations, even at an extremely low concentration of 0.05 mM, showcasing the 51.58 body length/s velocity. Furthermore, they can also respond to physiological pH values ranging from 4.4 to 7.4, exhibiting reduced mobility with increasing pH. This charge reversal-based responsive nanomotor design utilizing PST nanoparticles holds great promise for advancing the application of nanomotors within complex biological systems.

FE-Net: Feature enhancement segmentation network.

Semantic segmentation is one of the directions in image research. It aims to obtain the contours of objects of interest, facilitating subsequent engineering tasks such as measurement and feature selection. However, existing segmentation methods still lack precision in class edge, particularly in multi-class mixed region. To this end, we present the Feature Enhancement Network (FE-Net), a novel approach that leverages edge label and pixel-wise weights to enhance segmentation performance in complex backgrounds. Firstly, we propose a Smart Edge Head (SE-Head) to process shallow-level information from the backbone network. It is combined with the FCN-Head and SepASPP-Head, located at deeper layers, to form a transitional structure where the loss weights gradually transition from edge labels to semantic labels and a mixed loss is also designed to support this structure. Additionally, we propose a pixel-wise weight evaluation method, a pixel-wise weight block, and a feature enhancement loss to improve training effectiveness in multi-class regions. FE-Net achieves significant performance improvements over baselines on publicly datasets Pascal VOC2012, SBD, and ATR, with best mIoU enhancements of 15.19%, 1.42% and 3.51%, respectively. Furthermore, experiments conducted on Pole&Hole match dataset from our laboratory environment demonstrate the superior effectiveness of FE-Net in segmenting defined key pixels.

Monitoring of copper adsorption on biochar using spectral induced polarization method.

Copper contaminant generated from mining and industrial smelting poses potential risks to human health. Biochar, as a low-energy and cost-effective biomaterial, holds value in Cu remediation. Spectral Induced Polarization (SIP) technique is employed in this study to monitor the Cu remediation processes of by biochar in column experiments. Cation exchange at low Cu2+ concentrations and surface complexation at high Cu2+ concentrations are identified as the major mechanisms for copper retention on biochar. The normalized chargeability (mn) from SIP signals linearly decreased (R2 = 0.776) with copper retention under 60 mg/L Cu influent; while mn linearly increases (R2 = 0.907, 0.852) under high 300 and 700 mg/L Cu influents. The characteristic polarizing unit sizes (primarily the pores adsorbing Cu2+) calculated from Schwartz equation match well with experimental results by mercury intrusion porosimetry (MIP). It is revealed that Cu2+ was driven to small pores (∼3 µm) given high concentration gradient (influent Cu2+ concentration of 700 mg/L). Comparing to activated carbon, biochar is identified as an ideal adsorbent for Cu remediation, given its high adsorption capacity, cost-effectiveness, carbon-sink ability, and high sensitivity to SIP responses - the latter facilitates its performance assessment.

Synthesis and Properties of Bright Red-to-NIR BODIPY Dyes for Targeting Fluorescence Imaging and Near-Infrared Photothermal Conversion.

An efficient synthesis of 3-pyrrolylBODIPY dyes has been developed from a rational mixture of various aromatic aldehydes and pyrrole in a straightforward condensation reaction, followed by in situ successively oxidative nucleophilic substitution using a one-pot strategy. These resultant 3-pyrrolylBODIPYs without blocking substituents not only exhibit the finely tunable photophysical properties induced by the flexible meso-aryl substituents but also serve as a valuable synthetic framework for further selective functionalization. As a proof of such potential, one 3-pyrrolylBODIPY dye (581/603 nm) through the installation of the morpholine group is applicable for lysosome-targeting imaging. Furthermore, an ethene-bridged 3,3'-dipyrrolylBODIPY dimer was constructed, which displayed a near-infrared (NIR) emission extended to 1200 nm with a large fluorescence brightness (2840 M-1 cm-1). The corresponding dimer nanoparticles (NPs) afforded a high photothermal conversion efficiency (PCE) value of 72.5%, eventually resulting in favorable photocytotoxicity (IC50 = 9.4 µM) and efficient in vitro eradication of HeLa cells under 808 nm laser irradiation, highlighting their potential application for photothermal therapy in the NIR window.

CRISPR-Cas9-mediated chicken prmt5 gene knockout and its critical role in interferon regulation.

Protein arginine methyltransferase 5 (PRMT5), a type II arginine methyltransferase, controls arginine dimethylation of a variety of substrates. While many papers have reported the function of mammalian PRMT5, it remains unclear how PRMT5 functions in chicken cells. In this study, we found that chicken (ch) PRMT5 is widely expressed in a variety of chicken tissues and is distributed in both the cytoplasm and the nucleus. Ectopic expression of chPRMT5 significantly suppresses chIFN-ß activation induced by chMDA5. In addition, a prmt5 gene-deficient DF-1 cell line was constructed using CRISPR/Cas9. In comparison with the wild-type cells, the prmt5-/- DF-1 cells displays normal morphology and maintain proliferative capacity. Luciferase reporter assay and overexpression showed that prmt5-/- DF-1 cells had increased IFN-ß production. With identified chicken PRMT5 and CRISPR/Cas9 knockout performed in DF-1 cells, we uncovered a functional link of chPRMT5 in suppression of IFN-ß production and interferon-stimulated gene expression.

SB431542 partially inhibits high glucose-induced EMT by restoring mitochondrial homeostasis in RPE cells.

BACKGROUND: The epithelial-mesenchymal transition (EMT) of retinal pigment epithelial (RPE) cells participated in the development of retinal fibrosis. SB431542 is a small molecule inhibitor with inhibitory effects on the ALK4, ALK5 and ALK7. Our study aimed to explore the effect of SB431542 on the EMT of RPE cells and to provide new ideas for the treatment of retinal fibrosis. METHODS: We performed fundus fluorescein angiography, optical coherence tomography and hematoxylin-eosin staining in vivo to observe the effect of SB431542 on choroidal neovascularization (CNV)-induced retinopathy. The proliferation, migration, cytoskeleton, adhesion, reactive oxygen species (ROS), mitochondrial morphology and membrane potential of RPE cells were observed in vitro through fluorescein diacetate staining, Cell Counting Kit-8 experiment, wound healing assay, phalloidin staining, immunofluorescence, MitoSOX, DCFH-DA, MitoTracker and JC-10 staining. Western blot, reverse transcription quantitative and immunofluorescence were used to detect the expression of EMT-related markers, pERK1/2, pGSK3ß and ß-catenin. RESULTS: SB431542 significantly alleviated retinopathy in the CNV model. The proliferation, migration and adhesion in RPE cells decreased to a certain extent in SB431542 treatment. SB431542 partially normalized the structure of RPE cells. The expression levels of E-cadherin increased, while the expression levels of laminin and N-cadherin decreased with SB431542 treatment. SB431542 reduced the production of total ROS, mitochondrial SOX and recovered the mitochondrial membrane potential to a certain degree. In addition, our study showed that SB431542 downregulated the phosphorylation of ERK1/2, GSK3ß and the expression of ß-catenin. CONCLUSION: SB431542 improved EMT in RPE cells by maintaining mitochondrial homeostasis via the ERK1/2 and GSK3ß/ß-catenin pathways. Video Abstract SB431542 inhibits EMT in RPE cells under high glucose conditions.

The origin of bi-dimensionality in plant root traits.

Plant roots show extraordinary diversity in form and function in heterogeneous environments. Mounting evidence has shown global bi-dimensionality in root traits, the root economics spectrum (RES), and an orthogonal dimension describing mycorrhizal collaboration; however, the origin of the bi-dimensionality remains unresolved. Here, we propose that bi-dimensionality arises from the cylindrical geometry of roots, allometry between root cortex and stele, and independence between root cell wall thickness and cell number. Root geometry and mycorrhizal collaboration may both underlie the bi-dimensionality. Further, we emphasize why plant roots should be cylindrical rather than flat. Finally, we highlight the need to integrate organ-, cellular-, and molecular-level processes driving the bi-dimensionality in plant roots to fully understand plant diversity and functions.

Chimeric antigen receptor T cells to target CD79b in B-cell lymphomas.

BACKGROUND: Chimeric antigen receptor (CAR) T cells targeting CD19 mediate potent and durable effects in B-cell malignancies. However, antigen loss or downregulation is a frequent cause of resistance. Here, we report development of a novel CAR T-cell therapy product to target CD79b, a pan B-cell antigen, widely expressed in most B-cell lymphomas. METHODS: We generated a novel anti-CD79b monoclonal antibody by hybridoma method. The specificity of the antibody was determined by testing against isogenic cell lines with human CD79b knock-in or knock-out. A single-chain variable fragment derived from the monoclonal antibody was used to make a panel of CD79b-targeting CAR molecules containing various hinge, transmembrane, and co-stimulatory domains. These were lentivirally transduced into primary T cells and tested for antitumor activity in in vitro and in vivo B-cell lymphoma models. RESULTS: We found that the novel anti-CD79b monoclonal antibody was highly specific and bound only to human CD79b and no other cell surface protein. In testing the various CD79b-targeting CAR molecules, superior antitumor efficacy in vitro and in vivo was found for a CAR consisting CD8α hinge and transmembrane domains, an OX40 co-stimulatory domain, and a CD3ζ signaling domain. This CD79b CAR specifically recognized human CD79b-expressing lymphoma cell lines but not CD79b knock-out cell lines. CD79b CAR T cells, generated from T cells from either healthy donors or patients with lymphoma, proliferated, produced cytokines, degranulated, and exhibited robust cytotoxic activity in vitro against CD19+ and CD19- lymphoma cell lines and patient-derived lymphoma tumors relapsing after prior CD19 CAR T-cell therapy. Furthermore, CD79b CAR T cells were highly efficient at eradicating pre-established lymphoma tumors in vivo in three aggressive lymphoma xenograft models, including two cell line-derived xenografts and one patient-derived xenograft. Notably, these CAR T cells did not demonstrate any significant tonic signaling activity or markers of exhaustion. CONCLUSION: Our results indicated that this novel CD79b CAR T-cell therapy product has robust antitumor activity against B-cell lymphomas. These results supported initiation of a phase 1 clinical trial to evaluate this product in patients with relapsed or refractory B-cell lymphomas.

Propyrisulfuron plus cyhalofop butyl as one-shot herbicides provide high weed control efficiency and net economic performance in mechanically transplanted rice.

Propyrisulfuron is a novel pyrimidinylsulfonylurea herbicide with good activity for controlling annual weed in rice fields. To evaluate the economic performance of propyrisulfuron, a field study was conducted in 2021 and 2022 on a farm of the Jiangsu Academy of Agricultural Sciences, China. Eight different herbicide treatments were employed, including CB (cyhalofop butyl), Py (propyrisulfuron), CBPy (cyhalofop butyl plus propyrisulfuron), PrBe 3, PrBe 10, and PrBe 3+PrBe 10 (pretilachlor plus bensulfuron applied at different times [at 3 (PrBe 3) and 10 (PrBe 10) d] or sequentially, respectively), 2PrBe+PeCBBz (pretilachlor plus bensulfuron [applied sequentially] followed by penoxsulam plus cyhalofop butyl plus bentazone), 2PrBe+MeCBBz (pretilachlor plus bensulfuron [applied sequentially] followed by metamifop plus cyhalofop butyl plus bentazone), along with weed-free and nontreated weedy check treatments. Herbicide treatments did not cause visual phytotoxicity to rice, and bending and leaf rolling were not observed. Only the two propyrisulfuron treatments had temporary negative effects on rice height, but rice recovered quickly. Compared with the weed-free treatment, CBPy did not affect rice tiller number or dry matter accumulation. Compared with the nontreated weedy check, herbicide treatments reduced total weed density by 29.4% to 99.1% and dry biomass by 32.2% to 98.7%. The CBPy treatment provided the best weed control, reducing weed density and biomass by 96.7% and 95.9% in 2021 and 97.4% and 95.6% in 2022, respectively. Rice grain yield was not significantly different between CBPy and the weed-free treatment in either year. Economic analysis showed that CBPy provided the highest net profit, followed by that in 2PrBe+PeCBBz and 2PrBe+MeCBBz, with the lowest net profit in the nontreated weedy check. Thus, CBPy provides good weed control and could be promoted in mechanically transplanted rice fields in China.

Adjuvant effect of allogeneic blood in vaccines against edwardsiellosis in ginbuna crucian carp Carassius auratus langsdorfii.

Edwardsiella tarda (E. tarda), an intracellular pathogen, has caused severe economic losses in aquaculture. Effective vaccine development for E. tarda prevention is urgently needed. A previous study indicates that cell-mediated immunity (CMI) might play an important role in E. tarda infection. We believe that the involvement of allograft rejection and CMI has now been well documented in mammals and some fishes. However, there is still little research on the application of blood allograft rejection in vaccine development. In the current study, we investigate the immune response and vaccine effect in fish vaccinated with allogeneic blood + formalin-killed cells vaccine (FKC), allogeneic blood + phosphate-buffered saline (PBS), PBS + FKC and PBS + PBS. In the challenge test, the relative percentage survival (RPS) of the allogeneic + FKC, the allogeneic blood + PBS and the PBS + FKC group was 61.46, 35.41, and 30.63 % respectively. The up-regulated expression of Th1-related genes IFN-γ 1, IFN-γ 1rel2, IL-12p35 and T-bet suggests the protection is via CMI induction. Only in the allogeneic + FKC group, gene expression of IFN-γ 1, IL-12p35 and T-bet is significantly higher, indicating synergy between the two substances. Furthermore, among the fish injected with the allogeneic blood cells, syngeneic blood cells and PBS group, only in the fish of the allogenic blood cells injection group, did expression of IFN-γ 1, IFN-γ 2 and IFN-γ rel2 gene expression significantly increased. The results indicate that the rejection was induced by allogeneic components. Thus, our findings might provide essential information and insights into vaccine development in aquaculture.

MST4 kinase regulates immune thrombocytopenia by phosphorylating STAT1-mediated M1 polarization of macrophages.

Primary immune thrombocytopenia (ITP) is an autoimmune hemorrhagic disorder in which macrophages play a critical role. Mammalian sterile-20-like kinase 4 (MST4), a member of the germinal-center kinase STE20 family, has been demonstrated to be a regulator of inflammation. Whether MST4 participates in the macrophage-dependent inflammation of ITP remains elusive. The expression and function of MST4 in macrophages of ITP patients and THP-1 cells, and of a macrophage-specific Mst4-/- (Mst4ΔM/ΔM) ITP mouse model were determined. Macrophage phagocytic assays, RNA sequencing (RNA-seq) analysis, immunofluorescence analysis, coimmunoprecipitation (co-IP), mass spectrometry (MS), bioinformatics analysis, and phosphoproteomics analysis were performed to reveal the underlying mechanisms. The expression levels of the MST4 gene were elevated in the expanded M1-like macrophages of ITP patients, and this elevated expression of MST4 was restored to basal levels in patients with remission after high-dose dexamethasone treatment. The expression of the MST4 gene was significantly elevated in THP-1-derived M1 macrophages. Silencing of MST4 decreased the expression of M1 macrophage markers and cytokines, and impaired phagocytosis, which could be increased by overexpression of MST4. In a passive ITP mouse model, macrophage-specific depletion of Mst4 reduced the numbers of M1 macrophages in the spleen and peritoneal lavage fluid, attenuated the expression of M1 cytokines, and promoted the predominance of FcγRIIb in splenic macrophages, which resulted in amelioration of thrombocytopenia. Downregulation of MST4 directly inhibited STAT1 phosphorylation, which is essential for M1 polarization of macrophages. Our study elucidates a critical role for MST4 kinase in the pathology of ITP and identifies MST4 kinase as a potential therapeutic target for refractory ITP.