Protopine protects chondrocytes from undergoing ferroptosis by activating Nrf2 pathway

Osteoarthritis is a highly prevalent joint disease; however, effective treatments are lacking. Protopine (PTP) is an isoquinoline alkaloid with potent anti-inflammatory and antioxidant properties; however, it has not been studied in osteoarthritis. This study aimed to investigate whether PTP can effectively protect chondrocytes from ferroptosis. Primary mouse chondrocytes were treated with tert-butyl hydroperoxide (TBHP) to simulate oxidative stress in an in vitro model of osteoarthritis. Two concentrations of PTP (10 and 20 μg/mL) were validated for in vitro experiments. Cellular inflammation and metabolism were detected using RT-qPCR and western blotting (WB). Ferroptosis was assessed via WB, qPCR, reactive oxygen species (ROS) levels, lipid ROS, and immunofluorescence staining. In vitro, PTP significantly ameliorated chondrocyte inflammation and cytolytic metabolism and significantly suppressed chondrocyte ferroptosis through the activation of the Nrf2 pathway. The anterior cruciate ligament transection (ACLT) mouse model was used to validate the in vivo effects of PTP. The joint cartilage was assessed using the Osteoarthritis Research Society International (OARSI) score, Safranin O staining, and immunohistochemistry. The intra-articular administration of PTP alleviated cartilage inflammation and ferroptosis, as evidenced by the expression of MMP3, MMP13, COL2A1, GPX4, and Nrf2. Overall, we find that PTP exerted anti-ferroptosis and anti-inflammatory effects on chondrocytes to protect the articular cartilage.

The role of DNA damage in neural stem cells ageing

Neural stem cells (NSCs) are pluripotent stem cells with the potential to differentiate into a variety of nerve cells. NSCs are susceptible to both intracellular and extracellular insults, thus causing DNA damage. Extracellular insults include ultraviolet, ionizing radiation, base analogs, modifiers, alkyl agents and others, while intracellular factors include Reactive oxygen species (ROS) radicals produced by mitochondria, mismatches that occur during DNA replication, deamination of bases, loss of bases, and more. When encountered with DNA damage, cells typically employ three coping strategies: DNA repair, damage tolerance, and apoptosis. NSCs, like many other stem cells, have the ability to divide, differentiate, and repair DNA damage to prevent mutations from being passed down to the next generation. However, when DNA damage accumulates over time, it will lead to a series of alterations in the metabolism of cells, which will cause cellular ageing. The ageing and exhaustion of neural stem cell will have serious effects on the body, such as neurodegenerative diseases. The purpose of this review is to examine the processes by which DNA damage leads to NSCs ageing and the mechanisms of DNA repair in NSCs.

The Prospective Predictive Power of Parent-Reported Personality Traits and Facets in First-Onset Depression in Adolescent Girls

Certain personality traits and facets are well-known risk factors that predict first-onset depression during adolescence. However, prior research predominantly relied on self-reported data, which has limitations as a source of personality information. Reports from close informants have the potential to increase the predictive power of personality on first-onsets of depression in adolescents. With easy access to adolescents' behaviors across settings and time, parents may provide important additional information about their children's personality. The same personality trait(s) and facet(s) rated by selves (mean age 14.4 years old) and biological parents at baseline were used to prospectively predict depression onsets among 442 adolescent girls during a 72-month follow-up. First, bivariate logistic regression was used to examine whether parent-reported personality measures predicted adolescent girls' depression onsets; then multivariate logistic regression was used to test whether parent reports provided additional predictive power above and beyond self-reports of same trait or facet. Parent-reported personality traits and facets predicted adolescents' depression onsets, similar to findings using self-reported data. After controlling for the corresponding self-report measures, parent-reported higher openness (at the trait level) and higher depressivity (at the facet-level) incrementally predicted first-onset of depression in the sample. Findings demonstrated additional variance contributed by parent-reported personality measures and validated a multi-informant approach in using personality to prospectively predict onsets of depression in adolescent girls.

Design of a Zn-based nanozyme injectable multifunctional hydrogel with ROS scavenging activity for myocardial infarction therapy

The existing strategies for myocardial infarction therapy mainly focus on reinstating myocardial blood supply, often disregarding the intrinsic and intricate microenvironment created by elevated levels of reactive oxygen species (ROS) that accompanies myocardial infarction. This microenvironment entails cardiomyocytes apoptosis, substantial vascular cell death, excessive inflammatory infiltration and fibrosis. In such situation, the present study introduces a zinc-based nanozyme injectable multifunctional hydrogel, crafted from ZIF-8, to counteract ROS effects after myocardial infarction. The hydrogel exhibits both superoxide dismutase (SOD)-like and catalase (CAT)-like enzymatic activities, proficiently eliminating surplus ROS in the infarcted region and interrupting ROS-driven inflammatory cascades. Furthermore, the hydrogel's exceptional immunomodulatory ability spurs a notable transformation of macrophages into the M2 phenotype, effectively neutralizing inflammatory factors and indirectly fostering vascularization in the infarcted region. For high ROS and demanding for zinc of the infarcted microenvironment, the gradual release of zinc ions as the hydrogel degrades further enhances the bioactive and catalytic performance of the nanozymes, synergistically promoting cardiac function post myocardial infarction. In conclusion, this system of deploying catalytic nanomaterials within bioactive matrices for ROS-related ailment therapy not only establishes a robust foundation for biomedical material development, but also promises a holistic approach towards addressing myocardial infarction complexities. STATEMENT OF SIGNIFICANCE: Myocardial infarction remains the leading cause of death worldwide. However, the existing strategies for myocardial infarction therapy mainly focus on reinstating myocardial blood supply. These therapies often ignore the intrinsic and intricate microenvironment created by elevated levels of reactive oxygen species (ROS). Hence, we designed an injectable Zn-Based nanozyme hydrogel with ROS scavenging activity for myocardial infarction therapy. ALG-(ZIF-8) can significantly reduce ROS in the infarcted area and alleviate the ensuing pathological process. ALG-(ZIF-8) gradually releases zinc ions to participate in the repair process and improves cardiac function. Overall, this multifunctional hydrogel equipped with ZIF-8 makes full use of the characteristics of clearing ROS and slowly releasing zinc ions, and we are the first to test the therapeutic efficacy of Zinc-MOFs crosslinked-alginate hydrogel for myocardial infarction.

Uncovering the Genetic Etiology of Inherited Bone Marrow Failure Syndromes Using a Custom-Designed Next-Generation Sequencing Panel

Inherited bone marrow failure syndromes (IBMFS) are a group of heterogeneous disorders that account for ∼30% of pediatric cases of bone marrow failure and are often associated with developmental abnormalities and cancer predisposition. This article reports the laboratory validation and clinical utility of a large-scale, custom-designed next-generation sequencing panel, Children's Hospital of Philadelphia (CHOP) IBMFS panel, for the diagnosis of IBMFS in a cohort of pediatric patients. This panel demonstrated excellent analytic accuracy, with 100% sensitivity, ≥99.99% specificity, and 100% reproducibility on validation samples. In 269 patients with suspected IBMFS, this next-generation sequencing panel was used for identifying single-nucleotide variants, small insertions/deletions, and copy number variations in mosaic or nonmosaic status. Sixty-one pathogenic/likely pathogenic variants (54 single-nucleotide variants/insertions/deletions and 7 copy number variations) and 24 hypomorphic variants were identified, resulting in the molecular diagnosis of IBMFS in 21 cases (7.8%) and exclusion of IBMFS with a diagnosis of a blood disorder in 10 cases (3.7%). Secondary findings, including evidence of early hematologic malignancies and other hereditary cancer-predisposition syndromes, were observed in 9 cases (3.3%). The CHOP IBMFS panel was highly sensitive and specific, with a significant increase in the diagnostic yield of IBMFS. These findings suggest that next-generation sequencing-based panel testing should be a part of routine diagnostics in patients with suspected IBMFS.

Pip5k1c expression in osteocytes regulates bone remodeling in mice

Research background

The role of osteocytes in maintaining bone mass has been progressively emphasized. Pip5k1c is the most critical isoform among PIP5KIs, which can regulate cytoskeleton, biomembrane, and Ca2+ release of cells and participate in many processes, such as cell adhesion, differentiation, and apoptosis. However, its expression and function in osteocytes are still unclear.

Materials and methods

To determine the function of Pip5k1c in osteocytes, the expression of Pip5k1c in osteocytes was deleted by breeding the 10-kb mouse Dmp1-Cre transgenic mice with the Pip5k1cfl/fl mice. Bone histomorphometry, micro-computerized tomography analysis, immunofluorescence staining and western blotting were used to determine the effects of Pip5k1c loss on bone mass. In vitro, we explored the mechanism by siRNA knockdown of Pip5k1c in MLO-Y4 cells.

Results

Pip5k1c expression was decreased in osteocytes in senescent and osteoporotic tissues both in humans and mice. Loss of Pip5k1c in osteocytes led to a low bone mass in long bones and spines and impaired biomechanical properties in femur, without changes in calvariae. The loss of Pip5k1c resulted in the reduction of the protein level of type 1 collagen in tibiae and MLO-Y4 cells. Osteocyte Pip5k1c loss reduced the osteoblast and bone formation rate with high expression of sclerostin, impacting the osteoclast activities at the same time. Moreover, Pip5k1c loss in osteocytes reduced expression of focal adhesion proteins and promoted apoptosis.

Conclusion

Our studies demonstrate the critical role and mechanism of Pip5k1c in osteocytes in regulating bone remodeling.

The translational potential of this article

Osteocyte has been considered to a key role in regulating bone homeostasis. The present study has demonstrated that the significance of Pip5k1c in bone homeostasis by regulating the expression of collagen, sclerostin and focal adhesion expression, which provided a possible therapeutic target against human metabolic bone disease.

Genomic profiling of pediatric hematologic malignancies and diagnosis of cancer predisposition syndromes: tumor-only versus paired tumor-normal sequencing

Not available.

Role of c-Fos in DNA damage repair

c-Fos, a member of the immediate early gene, serves as a widely used marker of neuronal activation induced by various types of brain damage. In addition, c-Fos is believed to play a regulatory role in DNA damage repair. This paper reviews the literature on c-Fos' involvement in the regulation of DNA damage repair and indicates that genes of the Fos family can be induced by various forms of DNA damage. In addition, cells lacking c-Fos have difficulties in DNA repair. c-Fos is involved in tumorigenesis and progression as a proto-oncogene that maintains cancer cell survival, which may also be related to DNA repair. c-Fos may impact the repair of DNA damage by regulating the expression of downstream proteins, including ATR, ERCC1, XPF, and others. Nonetheless, the underlying mechanisms necessitate further exploration.

Kindlin-2 maintains liver homeostasis by regulating GSTP1-OPN-mediated oxidative stress and inflammation in mice

Hepatocyte plays a principal role in preserving integrity of the liver homeostasis. Our recent study demonstrated that Kindlin-2, a focal adhesion protein that activates integrins and regulates cell-extracellular matrix interactions, plays an important role in regulation of liver homeostasis by inhibiting inflammation pathway; however, the molecular mechanism of how Kindlin-2 KO activates inflammation is unknown. Here, we show that Kindlin-2 loss largely downregulates the antioxidant glutathione-S-transferase P1 in hepatocytes by promoting its ubiquitination and degradation via a mechanism involving protein-protein interaction. This causes overproduction of intracellular reactive oxygen species and excessive oxidative stress in hepatocytes. Kindlin-2 loss upregulates osteopontin in hepatocytes partially because of upregulation of reactive oxygen species and consequently stimulates overproduction of inflammatory cytokines and infiltration in liver. The molecular and histological deteriorations caused by Kindlin-2 deficiency are markedly reversed by systemic administration of an antioxidant N-acetylcysteine in mice. Taken together, Kindlin-2 plays a pivotal role in preserving integrity of liver function.

The bone-liver interaction modulates immune and hematopoietic function through Pinch-Cxcl12-Mbl2 pathway

Mesenchymal stromal cells (MSCs) are used to treat infectious and immune diseases and disorders; however, its mechanism(s) remain incompletely defined. Here we find that bone marrow stromal cells (BMSCs) lacking Pinch1/2 proteins display dramatically reduced ability to suppress lipopolysaccharide (LPS)-induced acute lung injury and dextran sulfate sodium (DSS)-induced inflammatory bowel disease in mice. Prx1-Cre; Pinch1f/f; Pinch2-/- transgenic mice have severe defects in both immune and hematopoietic functions, resulting in premature death, which can be restored by intravenous injection of wild-type BMSCs. Single cell sequencing analyses reveal dramatic alterations in subpopulations of the BMSCs in Pinch mutant mice. Pinch loss in Prx1+ cells blocks differentiation and maturation of hematopoietic cells in the bone marrow and increases production of pro-inflammatory cytokines TNF-α and IL-1β in monocytes. We find that Pinch is critical for expression of Cxcl12 in BMSCs; reduced production of Cxcl12 protein from Pinch-deficient BMSCs reduces expression of the Mbl2 complement in hepatocytes, thus impairing the innate immunity and thereby contributing to infection and death. Administration of recombinant Mbl2 protein restores the lethality induced by Pinch loss in mice. Collectively, we demonstrate that the novel Pinch-Cxcl12-Mbl2 signaling pathway promotes the interactions between bone and liver to modulate immunity and hematopoiesis and may provide a useful therapeutic target for immune and infectious diseases.

Advances in Dyslipidaemia Treatments: Focusing on ApoC3 and ANGPTL3 Inhibitors

Apolipoprotein C3 (apoC3) and angiopoietin-like protein 3 (ANGPTL3) inhibit lipolysis by lipoprotein lipase and may influence the secretion and uptake of various lipoproteins. Genetic studies show that depletion of these proteins is associated with improved lipid profiles and reduced cardiovascular events so it was anticipated that drugs which mimic the effects of loss-of-function mutations would be useful lipid treatments. ANGPTL3 inhibitors were initially developed as a treatment for severe hypertriglyceridaemia including familial chylomicronaemia syndrome (FCS), which is usually not adequately controlled with currently available drugs. However, it was found ANGPTL3 inhibitors were also effective in reducing low-density lipoprotein cholesterol (LDL-C) and they were studied in patients with homozygous familial hypercholesterolaemia (FH). Evinacumab targets ANGPTL3 and reduced LDL-C by about 50% in patients with homozygous FH and it has been approved for that indication. The antisense oligonucleotide (ASO) vupanorsen targeting ANGPTL3 was less effective in reducing LDL-C in patients with moderate hypertriglyceridaemia and its development has been discontinued but the small interfering RNA (siRNA) ARO-ANG3 is being investigated in Phase 2 studies. ApoC3 can be inhibited by the ASO volanesorsen, which reduced triglycerides by >70% in patients with FCS and it was approved for FCS in Europe but not in the United States because of concerns about thrombocytopaenia. Olezarsen is an N-acetylgalactosamine-conjugated ASO targeting apoC3 which appears as effective as volanesorsen without the risk of thrombocytopaenia and is undergoing Phase 3 trials. ARO-APOC3 is an siRNA targeting apoC3 that is currently being investigated in Phase 3 studies.

Estrogen receptor α inhibits Caveolin 1 translation by promoting m6A-dependent miR199a-5p maturation to confer nab-paclitaxel resistance

Estrogen receptor positive (ER+) breast cancer patients exhibit poorer responsiveness to nab-paclitaxel compared to ER negative (ER-) patients, with the underlying mechanisms remaining unknown. Caveolin 1 (CAV1) is a membrane invagination protein critical for the endocytosis of macromolecules including albumin-bound chemotherapeutic agents. Here, we demonstrate that ERα limits the efficacy of nab-paclitaxel in breast cancer cells while genetic or pharmacological inhibition of ERα increased the sensitivity of ER+ breast cancer cells to nab-paclitaxel. Notably, CAV1 expression inversely correlates with ERα and relates to improved clinical outcomes from nab-paclitaxel treatment. Importantly, ERα stimulates m6A dependent maturation of miR199a-5p, which is elevated in ER+ breast cancer, to inhibit CAV1 translation by antagonizing m6A modification of CAV1 mRNA. Together, our findings reveal a novel role of ERα in promoting m6A modification and subsequent maturation of miR199a-5p, which is upregulated in ER+ breast cancer, leading to the suppression of m6A modification of CAV1 and its mRNA translation, thereby contributing to nab-paclitaxel resistance. Thus, combining an ER antagonist with nab-paclitaxel could offer a promising strategy for treating ER+ breast cancer patients.

Investigation on repairing diabetic foot ulcer based on 3D bio-printing Gel/dECM/Qcs composite scaffolds

Diabetic foot ulcers are one of the most serious of the numerous complications of diabetes mellitus, causing great physical trauma and financial stress to patients, and accelerating wound healing in diabetic patients remains one of the major clinical challenges. Exosomes from adipose-derived stem cells can directly and indirectly promote wound healing. However, due to the low retention rate of exosomes in the wound, exosome treatment is difficult to achieve the expected effect. Therefore, it is of great significance to synthesize a composite scaffold that can stably load exosomes and has antibacterial properties. In this study, fresh pig skin was decellularized to obtain decellularized matrix (dECM). Secondly, quaternized chitosan (Qcs) was modified with quaternary ammonium salt to make it soluble in water after quaternization. Finally, Gel-dECM-Qcs (GDQ) bioink was prepared by adding acellular matrix and quaternized chitosan with temperature sensitive gelatin (Gel) as carrier. Tissue engineered composite scaffolds were then prepared by extrusion 3D printing technology. Subsequently, the physicochemical properties, biocompatibility and antimicrobial capacity of the composite scaffolds were determined, and the data showed that the composite scaffolds had good mechanical properties, biocompatibility and antimicrobial capacity, and the maximum stress of the composite scaffolds was 1.16 ± 0.05 MPa, the composite scaffolds were able to proliferate and adhered to the L929 cells, and the kill rates of composite scaffolds against E. coli and S. aureus after incubation for 24 h were 93.24 ± 1.22 % and 97.34 ± 0.23 %, respectively. Overall, the GDQ composite scaffolds have good mechanical properties adapted to skin bending, its good biocompatibility can promote the growth and migration of fibroblasts, reshape injured tissues, accelerate the wound healing, and excellent antimicrobial ability can inhibit the growth of E. coli and S. aureus, reducing the impact of bacterial infections on wounds. Moreover, the composite scaffolds have the potential to be used as exosom-loaded hydrogel dressings, which provides a basis for the subsequent research on the repair of diabetic foot ulcers.

An Intrinsically Magnetic Epicardial Patch for Rapid Vascular Reconstruction and Drug Delivery

Myocardial infarction (MI) is a major cause of mortality worldwide. The major limitation of regenerative therapy for MI is poor cardiac retention of therapeutics, which results from an inefficient vascular network and poor targeting ability. In this study, a two-layer intrinsically magnetic epicardial patch (MagPatch) prepared by 3D printing with biocompatible materials like poly (glycerol sebacate) (PGS) is designed, poly (ε-caprolactone) (PCL), and NdFeB. The two-layer structure ensured that the MagPatch multifariously utilized the magnetic force for rapid vascular reconstruction and targeted drug delivery. MagPatch accumulates superparamagnetic iron oxide (SPION)-labelled endothelial cells, instantly forming a ready-implanted organization, and rapidly reconstructs a vascular network anastomosed with the host. In addition, the prefabricated vascular network within the MagPatch allowed for the efficient accumulation of SPION-labelled therapeutics, amplifying the therapeutic effects of cardiac repair. This study defined an extendable therapeutic platform for vascularization-based targeted drug delivery that is expected to assist in the progress of regenerative therapies in clinical applications.

Efficient ocular delivery of siRNA via pH-sensitive vehicles for corneal neovascularization inhibition

Corneal neovascularization (CoNV)-induced blindness is an enduring and challenging condition with limited management options. Small interfering RNA (siRNA) is a promising strategy for preventing CoNV. This study reported a new strategy using siVEGFA to silence vascular endothelial growth factor A (VEGFA) for CoNV treatment. To improve the efficacy of siVEGFA delivery, a pH-sensitive polycationic mPEG_2k-PAMA₃₀-P(DEA₂₉-D5A₂₉) (TPPA) was fabricated. TPPA/siVEGFA polyplexes enter cells via clathrin-mediated endocytosis, resulting in higher cellular uptake efficiency and comparable silencing efficiency than that of Lipofectamine 2000 in vitro. Hemolytic assays verified that TPPA safe in normal physiological environments (pH 7.4) but can easily destroy membranes in acidic mature endosomes (pH 4.0). Studies on the distribution of TPPA in vivo showed that it could prolong the retention time of siVEGFA and promote its penetration in the cornea. In a mouse model induced by alkali burn, TPPA efficiently delivered siVEGFA to the lesion site and achieved VEGFA silencing efficiency. Importantly, the inhibitory effect of TPPA/siVEGFA on CoNV was comparable to that of the anti-VEGF drug ranibizumab. Delivering siRNA using pH-sensitive polycations to the ocular environment provides a new strategy to efficiently inhibit CoNV.

Suppression of alpha-tubulin acetylation potentiates therapeutic efficacy of Eribulin in liver cancer

Hepatocellular carcinoma (HCC) is a prevalent cancer with limited effective treatments. Eribulin mesylate is a novel chemotherapy drug that inhibits microtubule elongation and may impact the tumor microenvironment and immune pathway. This study aims to investigate the impact of changes in microtubule acetylation levels on HCC development and treatment outcomes. Clinical and molecular data were aggregated from databases, with survival analysis conducted to evaluate the relevance of microtubule acetylation. In vitro experiments using HCC cell lines and a tumor cell transplantation model in C57BL/c mice were performed to investigate the effects of microtubule acetylation on Eribulin treatment. A significant correlation was found between the level of lysine 40 acetylation of α-tubulin (acetyl-α-tubulin-lys40) and overall survival of HCC patients, with a better prognosis associated with a lower level of acetyl-α-tubulin-lys40. Knocking down ATAT1 or overexpressing HDAC6 reduced the level of acetyl-α-tubulin-lys40 and sensitized Eribulin treatment both in vitro and in vivo. In summary, acetyl-α-tubulin-lys40 was increased in HCC and was associated with a shorter overall survival of HCC patients. Reducing the level of acetyl-α-tubulin-lys40 can enhance sensitivity to Eribulin treatment both in vitro and in vivo, thereby establishing acetyl-α-tubulin-lys40 as a potential prognostic marker and predictive indicator for Eribulin treatment in HCC patients.

Diallyl trisulfide improves spinal cord ischemia-reperfusion injury damage by activating AMPK to stabilize mitochondrial function

BACKGROUND

Spinal cord ischemia-reperfusion injury (SCII) is a catastrophic event, which can cause paraplegia in severe cases. In the reperfusion stage, oxidative stress was up-regulated, which aggravated the injury and apoptosis of neurons. As the main active ingredient of garlic, diallyl trisulfide (DATS) displays strong antioxidant capacity. However, it is unknown whether DATS can protect the neurons of SCII.

MATERIALS AND METHODS

In this study, the descending aorta at the distal end of the left subclavian artery was ligated and perfused again after 14 min. Samples including blood and spinal cord (L2-L5) were taken 24 h later for morphological and biochemical examination.

RESULTS

After SCII, the rats showed motor dysfunction, increase apoptosis, malondialdehyde content, mitochondrial biogenesis and dynamic balance disorder. After the application of DATS, the adenosine monophosphate activated protein kinase (AMPK) was activated, the mitochondrial damage was improved, the oxidative stress was weakened, and the neuronal damage was recovered to some extent. However, the addition of compound C significantly weakened the protective effect of DATS.

CONCLUSION

Oxidative stress caused by mitochondrial damage was one of the important mechanisms of neuronal damage in SCII. DATS could activate AMPK, stabilize mitochondrial biogenesis and dynamic balance, and reduce neuronal damage caused by oxidative stress.

Localized delivery of anti-inflammatory agents using extracellular matrix-nanostructured lipid carriers hydrogel promotes cardiac repair post-myocardial infarction

A challenge in treating cardiac injury is the low heart-specificity of the drugs. Nanostructured lipid carriers (NLCs) are a relatively new format of lipid nanoparticles which have been used to deliver RNA and drugs. However, lipid nanoparticles exhibit higher affinity to the liver than the heart. To improve the delivery efficiency of NLCs into the heart, NLCs can be embedded into a scaffold and be locally released. In this study, a cardiac extracellular matrix (ECM) hydrogel-NLC composite was developed as a platform for cardiac repair. ECM-NLC composite gels at physiological conditions and releases payloads into the heart over weeks. ECM-NLC hydrogel carrying colchicine, an anti-inflammation agent, improved cardiac repair after myocardial infarction in mice. Transcriptome analysis indicated that Egfr downstream effectors participated in ECM-NLC-colchicine induced heart repair. In conclusion, ECM-NLC hydrogel is a potential platform for sustained and localized delivery of biomolecules into the heart, and loading appropriate medicines further increases the therapeutic efficacy of ECM-NLC hydrogel for cardiovascular diseases.

Piezo1 activation accelerates osteoarthritis progression and the targeted therapy effect of artemisinin

INTRODUCTION

Osteoarthritis (OA) is a devastating whole-joint disease affecting a large population worldwide with no cure; its mechanism remains poorly defined. Abnormal mechanical stress is the main pathological factor of OA.

OBJECTIVES

To investigate the effects of Piezo1 activation on OA development and progression and to explore Piezo1-targeting OA treatment.

METHODS

The expression levels of Piezo1 were determined in human OA cartilage and experimental OA mice. Mice with genetic Piezo1 deletion in chondrocytes or intra-articular injection of the Piezo1 activator Yoda1 were utilized to determine the effects on DMM-induced OA progression. Effects of artemisinin (ART), a potent antimalarial drug, on Piezo1 activation, chondrocyte metabolism and OA lesions were determined.

RESULTS

Piezo1 expression was elevated in articular chondrocytes in human OA and DMM-induced mouse OA cartilage. Piezo1 deletion in chondrocytes largely attenuates DMM-induced OA-like phenotypes. In contrast, intra-articular injection of Yoda1 aggravates the knee joint OA lesions in mice. PIEZO1 activation increases, while PIEZO1 siRNA knockdown decreases, expression of RUNX2 and catabolic enzymes MMP13 and ADAMTS5 in primary human articular chondrocytes in a PI3K-AKT dependent manner. We have provided strong evidence supporting that ART is a novel and potent inhibitor of Piezo1 activation in primary OA-HACs and all cell lines examined, including human endothelial HUVEC cells, ATDC5 chondrocyte-like cells and MLO-Y4 osteocytes-like cells. Results from in vitro experiments confirmed that ART decreases the Yoda1-induced increases in the levels of OA-related genes and p-PI3K and p-AKT proteins in OA-HACs and alleviates DMM-induced OA lesions in mice.

CONCLUSIONS

We establish a critical role of Piezo1 in promoting OA development and progression and define ART as a potential OA treatment.

[Analysis of disease composition and primary surgical procedures in pediatric secondary glaucoma inpatients: a single-center study]

Objective: To analyze the disease composition and primary surgical procedures in pediatric inpatients with secondary glaucoma. Methods: A retrospective case series study was conducted. Clinical data of children aged≤16 years with secondary glaucoma who were admitted to the Zhongshan Ophthalmic Center, Sun Yat-sen University, between January 1, 2017, and December 31, 2021, were included. The patients were classified according to the Childhood Glaucoma Research Network (CGRN) classification system, and their diagnoses, underlying factors, gender, age of onset, affected eye(s), age and type of initial surgery, and ophthalmic examination data were analyzed. Statistical analysis was performed using Kruskal-Wallis rank sum test and χ2 test. Results: A total of 540 patients (744 eyes) were included in this study, comprising 319 males (59.1%) and 221 females (40.9%). Unilateral disease was observed in 336 cases (62.2%), while bilateral involvement was present in 204 cases (37.8%). The age of onset was 4.0 (0.0, 9.0) years, and the median age of the first anti-glaucoma surgery was 5.0 (0.7, 10.0) years. Among them, there were 195 cases (36.1%) of secondary glaucoma associated with non-acquired ocular anomalies (SCG-O), with a median age of onset of 0.0 (0.0, 4.0) years, and 97 of these cases (49.7%) were male. secondary glaucoma associated with non-acquired systemic disease or syndrome (SCG-S) were observed in 68 cases (12.6%), with a median age of glaucoma onset of 0.1 (0.0, 4.0) years, and 47 of these cases (69.1%) were male. Secondary glaucoma associated with acquired conditions (SCG-A) accounted for 192 cases (35.6%), with a median age of onset of 9.0 (5.0, 13.0) years, and 125 of these cases (65.1%) were male. There were 85 cases (15.7%) of secondary glaucoma following cataract surgery (SCG-C), with a median age of onset of 3.0 (0.8, 7.0) years, and 50 of these cases (58.8%) were male. Male patients were predominant in SCG-S and SCG-A, with 47 cases (69.1%) and 125 cases (65.1%), respectively (χ2=9.94, 17.52; P=0.002,<0.001). Except for SCG-O, all other types of pediatric secondary glaucoma predominantly affected only one eye: SCG-S in 52 cases (76.5%), SCG-A in 128 cases (66.7%), and SCG-C in 54 cases (63.5%) (χ2=19.06, 21.33, 6.22; all P<0.05). The highest proportion of SCG-O was attributed to congenital ectropion uveae (46 cases, 23.6%). Sturge-Weber syndrome was the most common SCG-S (45 cases, 66.3%), while SCG-A mostly resulted from trauma (59 cases, 30.8%) and corticosteroid use (56 cases, 29.2%). Trabeculectomy (211 eyes, 30.8%) and glaucoma drainage device implantation (197 eyes, 28.7%) were the most frequently performed primary surgical procedures. Conclusions: SCG-O and SCG-A were found to be common types of pediatric secondary glaucoma. The age of onset and the choice of primary anti-glaucoma surgical procedures varied among different types of pediatric secondary glaucoma. However, overall, trabeculectomy and glaucoma drainage device implantation were the primary surgical procedures predominantly employed.

Analysis of the genetic contribution to thoracic aortic aneurysm or dissection in a prospective cohort of patients with familial and sporadic cases in East China

BACKGROUND

Thoracic aortic aneurysm or dissections (TAADs) represent a group of life-threatening diseases. Genetic aetiology can affect the age of onset, clinical phenotype, and timing of intervention. We conducted a prospective trial to determine the prevalence of pathogenic variants in TAAD patients and to elucidate the traits related to harbouring the pathogenic variants. One hundred and one unrelated TAAD patients underwent genetic sequencing and analysis for 23 TAAD-associated genes using a targeted PCR and next-generation sequencing-based panel.

RESULTS

A total of 47 variants were identified in 52 TAAD patients (51.5%), including 5 pathogenic, 1 likely pathogenic and 41 variants of uncertain significance. The pathogenic or likely pathogenic (P/LP) variants in 4 disease-causing genes were carried by 1 patient with familial and 5 patients with sporadic TAAD (5.9%). In addition to harbouring one variant causing familial TAAD, the FBN1 gene harboured half of the P/LP variants causing sporadic TAAD. Individuals with an age of onset less than 50 years or normotension had a significantly increased genetic risk.

CONCLUSIONS

TAAD patients with a younger age at diagnosis or normotension were more likely to carry a P/LP variant; thus, routine genetic testing will be beneficial to a better prognosis through genetically personalized care prior to acute rupture or dissection.

Molecular epidemiology of clinical isolation of carbapenem-resistant Enterobacterales and application of carbapenemase inhibitor enhancement test

OBJECTIVES

The prevalence of carbapenem-resistant Enterobacterales (CRE) presents a significant challenge in clinical anti-infective treatment. This study aims to investigate drug resistance and the molecular epidemiological characteristics of CRE in our area. Additionally, we seek to evaluate practicality of utilizing carbapenemase inhibitor enhancement test in clinical laboratory.

METHODS

Non-repeated CREs isolated from clinical specimens at Xiangya Hospital, Central South University, were collected. Minimum inhibitory concentration (MIC) combined with Kirby-Bauer (KB) assay was used to detect the drug susceptibility of the strains, and 13 carbapenemase-producing genes were detected by PCR. The phenotype of 126 strains of carbapenemase-producing Enterobacterales identified by PCR was detected by the carbapenemase inhibitor enhancement test to understand the agreement between the method and the gold standard PCR results.

RESULTS

Among 704 CRE strains examined, we observed significant drug resistance in 501 strains dentified as carbapenemase-producing Enterobacterales (CPE). Klebsiella pneumoniae was the predominant CPE strain, followed by Enterobacter cloacae and Escherichia coli. A total of 9 carbapenemase types were detected, including Klebsiella pneumoniae carbapenemase (KPC), New Delhi metallo-β-lactamase (NDM), Verona integron- encoded metallo-β-lactamases (VIM), imipenemase (IMP), oxacillinase-48 (OXA-48), and rare imipenem-hydrolyzing β-lactamase (IMI), adelaide imipenemase (AIM), Bicêtre carbapenemase (BIC), and guiana extended-spectrum β-lactamase (GES). The detection rate of KPC serine carbapenemase was 61.7% (309/501). The carbapenemase inhibitor enhancement test exhibited a 100% consistency rate for the strains producing Class A serine carbapenemase and/or Class B metallo-β-lactamases.

CONCLUSIONS

CRE strains in Changsha, Hunan, China, are wide distribution and exhibit carbapenemase production. The main mechanism of carbapenem resistance in these bacterias is predominatly attributed to the production of KPC serine carbapenemase. The presence of GES and IMI genes carried by Enterobacterales has been detected for the first time in this region. The carbapenemase inhibitor enhancement test has been proven to be an accurate method for detecting CRE producing Class A serine carbapenemase and/or Class B metallo-β-lactamases. This method offers simpicity of operation and ease of results interpretation, making it weel-suited meeting the clinical microbiology laboratory's reguirements for the detection of serine carbapenemase and metallo-β-lactamases.

Research trends in cardiovascular tissue engineering from 1992 to 2022: a bibliometric analysis

Background

Cardiovascular tissue engineering (CTE) is a promising technique to treat incurable cardiovascular diseases, such as myocardial infarction and ischemic cardiomyopathy. Plenty of studies related to CTE have been published in the last 30 years. However, an analysis of the research status, trends, and potential directions in this field is still lacking. The present study applies a bibliometric analysis to reveal CTE research trends and potential directions.

Methods

On 5 August 2022, research articles and review papers on CTE were searched from the Web of Science Core Collection with inclusion and exclusion criteria. Publication trends, research directions, and visual maps in this field were obtained using Excel (Microsoft 2009), VOSviewer, and Citespace software.

Results

A total of 2,273 documents from 1992 to 2022 were included in the final analysis. Publications on CTE showed an upward trend from 1992 [number of publications (Np):1] to 2021 (Np:165). The United States (Np: 916, number of citations: 152,377, H-index: 124) contributed the most publications and citations in this field. Research on CTE has a wide distribution of disciplines, led by engineering (Np: 788, number of citations: 40,563, H-index: 105). "Functional maturation" [red cluster, average published year (APY): 2018.63, 30 times], "cell-derived cardiomyocytes" (red cluster, APY: 2018.43, 46 times), "composite scaffolds" (green cluster, APY: 2018.54, 41 times), and "maturation" (red cluster, APY: 2018.17, 84 times) are the main emerging keywords in this area.

Conclusion

Research on CTE is a hot research topic. The United States is a dominant player in CTE research. Interdisciplinary collaboration has played a critical role in the progress of CTE. Studies on functional maturation and the development of novel biologically relevant materials and related applications will be the potential research directions in this field.

TGF-β1 dominates stromal fibroblast-mediated EMT via the FAP/VCAN axis in bladder cancer cells

BACKGROUND

Bladder cancer is one of the most common malignant tumors of the urinary system and is associated with a poor prognosis once invasion and distant metastases occur. Epithelial-mesenchymal transition (EMT) drives metastasis and invasion in bladder cancer. Transforming growth factor β1 (TGF-β1) and stromal fibroblasts, especially cancer-associated fibroblasts (CAFs), are positive regulators of EMT in bladder cancer. However, it remains unclear how TGF-β1 mediates crosstalk between bladder cancer cells and CAFs and how it induces stromal fibroblast-mediated EMT in bladder cancer. We aimed to investigate the mechanism of TGF-β1 regulation of stromal fibroblast-mediated EMT in bladder cancer cells.

METHODS

Primary CAFs with high expression of fibroblast activation protein (FAP) were isolated from bladder cancer tissue samples. Subsequently, different conditioned media were used to stimulate the bladder cancer cell line T24 in a co-culture system. Gene set enrichment analysis, a human cytokine antibody array, and cytological assays were performed to investigate the mechanism of TGF-β1 regulation of stromal fibroblast-mediated EMT in bladder cancer cells.

RESULTS

Among the TGF-β family, TGF-β1 was the most highly expressed factor in bladder cancer tissue and primary stromal fibroblast supernatant. In the tumor microenvironment, TGF-β1 was mainly derived from stromal fibroblasts, especially CAFs. In stimulated bladder cells, stromal fibroblast-derived TGF-β1 promoted bladder cancer cell migration, invasion, and EMT. Furthermore, TGF-β1 promoted the activation of stromal fibroblasts, inducing CAF-like features, by upregulating FAP in primary normal fibroblasts and a normal fibroblast cell line. Stromal fibroblast-mediated EMT was induced in bladder cancer cells by TGF-β1/FAP. Versican (VCAN), a downstream molecule of FAP, plays an essential role in TGF-β1/FAP axis-induced EMT in bladder cancer cells. VCAN may also function through the PI3K/AKT1 signaling pathway.

CONCLUSIONS

TGF-β1 is a critical mediator of crosstalk between stromal fibroblasts and bladder cancer cells. We revealed a new mechanism whereby TGF-β1 dominated stromal fibroblast-mediated EMT of bladder cancer cells via the FAP/VCAN axis and identified potential biomarkers (FAP, VCAN, N-cadherin, and Vimentin) of bladder cancer. These results enhance our understanding of bladder cancer invasion and metastasis and provide potential strategies for diagnosis, treatment, and prognosis.

Stabilizing Supersaturation with Extreme Grain Refinement in Spinodal Aluminum Alloys

Supersaturated solid solutions can be formed in alloys from various non-equilibrium processes, but stabilizing the metastable phases against decomposition is challenging, particularly the spinodal decomposition which occurs via chemical fluctuations without energy barriers to nucleation. Herein, we found that spinodal decomposition in supersaturated Al(Zn) solid solutions can be inhibited with straining-induced extreme grain refinement. For the refined supersaturated grains in the nano-scale, their spinodal decomposition is obviously resisted by the relaxed grain boundaries and reduced lattice defects. As grains are refined below 10 nm the decomposition is completely inhibited, in which atomic diffusion are blocked by the stable Schwarz crystal structure with vacancy-free grains. The extreme grain refinement offers a general approach to stabilize supersaturated phases with broadened compositional windows for property modulation of alloys. This article is protected by copyright. All rights reserved.

HTRA1 from OVX rat osteoclasts causes detrimental effects on endplate chondrocytes through NF-κB

Endplate osteochondritis is considered one of the major causes of intervertebral disc degeneration (IVDD) and low back pain. Menopausal women have a higher rate of endplate cartilage degeneration than similarly aged men, but the related mechanisms are still unclear. Subchondral bone changes, mainly mediated by osteoblasts and osteoclasts, are considered an important reason for the degeneration of cartilage. This work explored the role of osteoclasts in endplate cartilage degeneration, as well as its underlying mechanisms. A rat ovariectomy (OVX) model was used to induce estrogen deficiency. Our experiments indicated that OVX significantly promoted osteoclastogenesis and anabolism and catabolism changes in endplate chondrocytes. OVX osteoclasts cause an imbalance between anabolism and catabolism in endplate chondrocytes, as shown by a decrease in anabolic markers such as Aggrecan and Collagen II, and an increase in catabolic markers such as a disintegrin and metalloproteinase with thrombospondin motifs 5 (ADAMTS5) and matrix metalloproteinases (MMP13). Osteoclasts were also confirmed in this study to be able to secrete HtrA serine peptidase 1 (HTRA1), which resulted in increased catabolism in endplate chondrocytes through the NF-κB pathway under estrogen deficiency. This study demonstrated the involvement and mechanism of osteoclasts in the anabolism and catabolism changes of endplate cartilage under estrogen deficiency, and proposed a new strategy for the treatment of endplate osteochondritis and IVDD by targeting HTRA1.

A Novel Defined PANoptosis-Related miRNA Signature for Predicting the Prognosis and Immune Characteristics in Clear Cell Renal Cell Carcinoma: A miRNA Signature for the Prognosis of ccRCC

Clear cell renal cell carcinoma (ccRCC) is one of the most prevalent cancers, and PANoptosis is a distinct, inflammatory-programmed cell death regulated by the PANoptosome. The essential regulators of cancer occurrence and progression are microRNAs (miRNAs). However, the potential function of PANoptosis-related microRNAs (PRMs) in ccRCC remains obscure. This study retrieved ccRCC samples from The Cancer Genome Atlas database and three Gene Expression Omnibus datasets. PRMs were recognized based on previous reports in the scientific literature. Regression analyses were used to identify the prognosis PRMs and construct a PANoptosis-related miRNA prognostic signature based on the risk score. We discovered that high-risk patients had poorer survival prognoses and were significantly linked to high-grade and advanced-stage tumors, using a variety of R software packages and web analysis tools. Furthermore, we demonstrated that the low-risk group had significant changes in their metabolic pathways. In contrast, the high-risk group was characterized by high immune cell infiltration, immune checkpoint expression, and low half-maximum inhibition concentration (IC50) values of chemotherapeutic agents. This suggests that high-risk patients may benefit more from immunotherapy and chemotherapy. In conclusion, we constructed a PANoptosis-related microRNA signature and revealed its potential significance in clinicopathological features and tumor immunity, thereby providing new precise treatment strategies.

Current hotspot and study trend of innate immunity in COVID-19: a bibliometric analysis from 2020 to 2022

Background

Since the coronavirus disease 2019 (COVID-19) has spread throughout the world, many studies on innate immunity in COVID-19 have been published, and great progress has been achieved, while bibliometric analysis on hotspots and research trends in this field remains lacking.

Methods

On 17 November 2022, articles and reviews on innate immunity in COVID-19 were recruited from the Web of Science Core Collection (WoSCC) database after papers irrelevant to COVID-19 were further excluded. The number of annual publications and the average citations per paper were analyzed by Microsoft Excel. Bibliometric analysis and visualization of the most prolific contributors and hotspots in the field were performed by VOSviewer and CiteSpace software.

Results

There were 1,280 publications that met the search strategy on innate immunity in COVID-19 and were published from 1 January 2020 to 31 October 2022. Nine hundred thirteen articles and reviews were included in the final analysis. The USA had the highest number of publications (Np) at 276 and number of citations without self-citations (Nc) at 7,085, as well as an H-index of 42, which contributed 30.23% of the total publications, followed by China (Np: 135, Nc: 4,798, and H-index: 23) with 14.79% contribution. Regarding Np for authors, Netea, Mihai G. (Np: 7) from the Netherlands was the most productive author, followed by Joosten, Leo A. B. (Np: 6) and Lu, Kuo-Cheng (Np: 6). The Udice French Research Universities had the most publications (Np: 31, Nc: 2,071, H-index: 13), with an average citation number (ACN) at 67. The journal Frontiers in Immunology possessed the most publications (Np: 89, Nc: 1,097, ACN: 12.52). "Evasion" (strength 1.76, 2021-2022), "neutralizing antibody" (strength 1.76, 2021-2022), "messenger RNA" (strength 1.76, 2021-2022), "mitochondrial DNA" (strength 1.51, 2021-2022), "respiratory infection" (strength 1.51, 2021-2022), and "toll-like receptors" (strength 1.51, 2021-2022) were the emerging keywords in this field.

Conclusion

The study on innate immunity in COVID-19 is a hot topic. The USA was the most productive and influential country in this field, followed by China. The journal with the most publications was Frontiers in Immunology. "Messenger RNA," "mitochondrial DNA," and "toll-like receptors" are the current hotspots and potential targets in future research.

Associations of Homocysteine, Folate, and Vitamin B12 with Osteoarthritis: A Mendelian Randomization Study

Homocysteine, inversely related to folate and vitamin B12, is an independent risk factor for several age-related disorders. However, little is known about the association of homocysteine and related vitamins with osteoarthritis (OA). This study aimed to elucidate the potential causal effects of homocysteine, folate, and vitamin B12 on site- and gender-specific OA by applying the two-sample Mendelian randomization (MR) approach. Genetically predicted homocysteine showed adverse effects on overall OA (95% confidence interval (CI): 1.044–1.155), knee OA (95% CI: 1.000–1.167), hip OA (95% CI: 1.057–1.297), and spine OA (95% CI: 1.017–1.216). Genetically predicted folate showed protective effects on overall OA (95% CI: 0.783–0.961) and spine OA (95% CI: 0.609–0.954). Folate (95% CI: 0.887–1.004) and vitamin B12 (95% CI: 0.886–1.009) showed a protective trend against knee OA. The patterns of associations were site and gender specific. In conclusion, homocysteine had adverse effects on OA, especially on OA at weight-bearing joints and in females. Folate and vitamin B12 had protective effects on OA. Homocysteine-lowering interventions may be a potential option in the treatment and prevention of OA.

Osteoarthritis: pathogenic signaling pathways and therapeutic targets

Osteoarthritis (OA) is a chronic degenerative joint disorder that leads to disability and affects more than 500 million population worldwide. OA was believed to be caused by the wearing and tearing of articular cartilage, but it is now more commonly referred to as a chronic whole-joint disorder that is initiated with biochemical and cellular alterations in the synovial joint tissues, which leads to the histological and structural changes of the joint and ends up with the whole tissue dysfunction. Currently, there is no cure for OA, partly due to a lack of comprehensive understanding of the pathological mechanism of the initiation and progression of the disease. Therefore, a better understanding of pathological signaling pathways and key molecules involved in OA pathogenesis is crucial for therapeutic target design and drug development. In this review, we first summarize the epidemiology of OA, including its prevalence, incidence and burdens, and OA risk factors. We then focus on the roles and regulation of the pathological signaling pathways, such as Wnt/β-catenin, NF-κB, focal adhesion, HIFs, TGFβ/ΒΜP and FGF signaling pathways, and key regulators AMPK, mTOR, and RUNX2 in the onset and development of OA. In addition, the roles of factors associated with OA, including MMPs, ADAMTS/ADAMs, and PRG4, are discussed in detail. Finally, we provide updates on the current clinical therapies and clinical trials of biological treatments and drugs for OA. Research advances in basic knowledge of articular cartilage biology and OA pathogenesis will have a significant impact and translational value in developing OA therapeutic strategies.

Triboelectric Nanogenerator-Based Near-Field Electrospinning System for Optimizing PVDF Fibers with High Piezoelectric Performance

Electrospinning is an effective method to prepare polyvinylidene fluoride (PVDF) piezoelectric fibers with a high-percentage β phase. However, as an energy conversion material for micro- and nanoscale diameters, PVDF fibers have not been widely used due to their disordered arrangement prepared by traditional electrospinning. Here, we designed a near-field electro-spinning (NFES) system driven by a triboelectric nanogenerator (TENG) to prepare PVDF fibers. The effects of five important parameters (PVDF concentration, needle inner diameter, TENG pulse DC voltage (TPD-voltage), flow rate, and drum speed) on the β phase fraction of PVDF fiber were optimized one by one. The results showed that the electrospun PVDF fibers had uniform diameter and controllable parallel arrangement. The β phase content of the optimized PVDF fiber reached 91.87 ± 0.61%. For the bending test of a single PVDF fiber piezoelectric device, when the strain is 0.098%, the electric energy of the single PVDF fiber device of NFES reaches 7.74 pJ and the energy conversion efficiency reaches 13.5%, which is comparable to the fibers prepared by the commercial power-driven NFES system. In 0.5 Hz, the best matching load resistance of a PVDF single fiber device is 10.6 MΩ, the voltage is 6.1 mV, and the maximum power is 3.52 pW. Considering that TENG can harvest micromechanical energy in the low frequency environment, the application scenario of the NFES system can be extended to the wild or remote mountainous areas without traditional high-voltage power supply. Therefore, the electrospun PVDF fibers in this system will have potential applications in high-precision 3D fabrication, self-powered sensors, and flexible wearable electronic products.

Kindlin-2 inhibits TNF/NF-κB-Caspase 8 pathway in hepatocytes to maintain liver development and function

Inflammatory liver diseases are a major cause of morbidity and mortality worldwide; however, underlying mechanisms are incompletely understood. Here we show that deleting the focal adhesion protein Kindlin-2 expression in hepatocytes using the Alb-Cre transgenic mice causes a severe inflammation, resulting in premature death. Kindlin-2 loss accelerates hepatocyte apoptosis with subsequent compensatory cell proliferation and accumulation of the collagenous extracellular matrix, leading to massive liver fibrosis and dysfunction. Mechanistically, Kindlin-2 loss abnormally activates the tumor necrosis factor (TNF) pathway. Blocking activation of the TNF signaling pathway by deleting TNF receptor or deletion of Caspase 8 expression in hepatocytes essentially restores liver function and prevents premature death caused by Kindlin-2 loss. Finally, of translational significance, adeno-associated virus mediated overexpression of Kindlin-2 in hepatocytes attenuates the D-galactosamine and lipopolysaccharide-induced liver injury and death in mice. Collectively, we establish that Kindlin-2 acts as a novel intrinsic inhibitor of the TNF pathway to maintain liver homeostasis and may define a useful therapeutic target for liver diseases.

HSF1 promotes CD69+ Treg differentiation to inhibit colitis progression

Regulatory T cells (Tregs) are critical for generating and maintaining peripheral tolerance. Treg-based immunotherapy is valuable for the clinical management of diseases resulting from dysregulation of immune tolerance. However, the lack of potency is a potential limitation of Treg therapy. In addition, CD69 positive-Treg (CD69⁺ Treg) represent a newly identified subset of Tregs with potent immune suppressive capability. Methods: Foxp3 ^YFP-Cre CD69 ^fl/fl and CD4 ^Cre CD69 ^fl/fl mice were generated to determine the relevance of CD69 to Treg. Chromatin Immunoprecipitation Assay (ChIP) and luciferase Assay were performed to detect the regulation of CD69 transcription by heat shock transcription factor 1(HSF1). Gene expression was measured by western blotting and qRT-PCR. The differentiation of naive T cells to CD69⁺Foxp3⁺ iTregs was determined by flow cytometry. The immunosuppressive ability of Tregs was analyzed by ELISA and flow cytometry. Colon inflammation in mice was reflected by changes in body weight and colon length, the disease activity index (DAI), and H&E staining of colon tissues. Results: Induced Tregs (iTregs) from CD4 ^Cre CD69 ^fl/fl mice failed to alleviate colitis. The transcription factor HSF1 interacted with the promoter of the CD69 gene to prompt its transcription during Treg differentiation. Genetic and chemical inhibition of HSF1 impaired CD69⁺ Treg differentiation and promoted the pathogenesis of colitis in mice. In contrast, HSF1 protein stabilized by inhibiting its proteasomal degradation promoted CD69⁺ Treg differentiation and alleviated colitis in mice. Moreover, adoptive transfer of iTregs with HSF1 stabilization by proteasome inhibitor (PSI) dramatically prevented the development of colitis in mice and was accompanied by decreased production of pro-inflammatory cytokines and reduced accumulation of pro-inflammatory lymphocytes in colitis tissue, whereas Tregs induced in the absence of PSI were less stable and ineffective in suppressing colitis. Conclusions: HSF1 promotes CD69⁺ Tregs differentiation by activating the CD69 transcription, which is critical for the immunosuppressive function of Tregs. Stabilization of HSF1 by PSIs results in the efficient generation of Tregs with high potency to treat colitis and probably other autoimmune diseases involving Tregs deficiency.

Bidirectional effects of oral anticoagulants on gut microbiota in patients with atrial fibrillation

Background

The imbalance of gut microbiota (GM) is associated with a higher risk of thrombosis in patients with atrial fibrillation (AF). Oral anticoagulants (OACs) have been found to significantly reduce the risk of thromboembolism and increase the risk of bleeding. However, the OAC-induced alterations in gut microbiota in patients with AF remain elusive.

Methods

In this study, the microbial composition in 42 AF patients who received long-term OAC treatment (AF-OAC group), 47 AF patients who did not (AF group), and 40 volunteers with the risk of AF (control group) were analyzed by 16S rRNA gene sequencing of fecal bacterial DNA. The metagenomic functional prediction of major bacterial taxa was performed using the Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) software package.

Results

The gut microbiota differed between the AF-OAC and AF groups. The abundance of Bifidobacterium and Lactobacillus decreased in the two disease groups at the genus level, but OACs treatment mitigated the decreasing tendency and increased beneficial bacterial genera, such as Megamonas. In addition, OACs reduced the abundance of pro-inflammatory taxa on the genus Ruminococcus but increased certain potential pathogenic taxa, such as genera Streptococcus, Escherichia-Shigella, and Klebsiella. The Subgroup Linear discriminant analysis effect size (LEfSe) analyses revealed that Bacteroidetes, Brucella, and Ochrobactrum were more abundant in the anticoagulated bleeding AF patients, Akkermansia and Faecalibacterium were more abundant in the non-anticoagulated-bleeding-AF patients. The neutrophil-to-lymphocyte ratio (NLR) was lower in the AF-OAC group compared with the AF group (P < 0.05). Ruminococcus was positively correlated with the NLR and negatively correlated with the CHA2DS2-VASc score (P < 0.05), and the OACs-enriched species (Megamonas and Actinobacteria) was positively correlated with the prothrombin time (PT) (P < 0.05). Ruminococcus and Roseburia were negatively associated with bleeding events (P < 0.05).

Conclusions

Our study suggested that OACs might benefit AF patients by reducing the inflammatory response and modulating the composition and abundance of gut microbiota. In particular, OACs increased the abundance of some gut microbiota involved in bleeding and gastrointestinal dysfunction indicating that the exogenous supplementation with Faecalibacterium and Akkermansia might be a prophylactic strategy for AF-OAC patients to lower the risk of bleeding after anticoagulation.

Bivalirudin plus a high-dose infusion versus heparin monotherapy in patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention: a randomised trial

BACKGROUND

Previous randomised trials of bivalirudin versus heparin in patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI) have reported conflicting results, in part because of treatment with different pharmacological regimens. We designed a large-scale trial examining bivalirudin with a post-PCI high-dose infusion compared with heparin alone, the regimens that previous studies have shown to have the best balance of safety and efficacy.

METHODS

BRIGHT-4 was an investigator-initiated, open-label, randomised controlled trial conducted at 87 clinical centres in 63 cities in China. Patients with STEMI undergoing primary PCI with radial artery access within 48 h of symptom onset who had not received previous fibrinolytic therapy, anticoagulants, or glycoprotein IIb/IIIa inhibitors were randomly assigned (1:1) to receive bivalirudin with a post-PCI high-dose infusion for 2-4 h or unfractionated heparin monotherapy. There was no masking. Glycoprotein IIb/IIIa inhibitor use was reserved for procedural thrombotic complications in both groups. The primary endpoint was a composite of all-cause mortality or Bleeding Academic Research Consortium (BARC) types 3-5 bleeding at 30 days. This trial is registered with ClinicalTrials.gov (NCT03822975), and is ongoing.

FINDINGS

Between Feb 14, 2019, and April 7, 2022, a total of 6016 patients with STEMI undergoing primary PCI were randomly assigned to receive either bivalirudin plus a high-dose infusion after PCI (n=3009) or unfractionated heparin monotherapy (n=3007). Radial artery access was used in 5593 (93·1%) of 6008 patients. Compared with heparin monotherapy, bivalirudin reduced the 30-day rate of the primary endpoint (132 events [4·39%] in the heparin group vs 92 events [3·06%] in the bivalirudin group; difference, 1·33%, 95% CI 0·38-2·29%; hazard ratio [HR] 0·69, 95% CI 0·53-0·91; p=0·0070). All-cause mortality within 30 days occurred in 118 (3·92%) heparin-assigned patients and in 89 (2·96%) bivalirudin-assigned patients (HR 0·75; 95% CI 0·57-0·99; p=0·0420), and BARC types 3-5 bleeding occurred in 24 (0·80%) heparin-assigned patients and five (0·17%) bivalirudin-assigned patients (HR 0·21; 95% CI 0·08-0·54; p=0·0014). There were no significant differences in the 30-day rates of reinfarction, stroke, or ischaemia-driven target vessel revascularisation between the groups. Within 30 days, stent thrombosis occurred in 11 (0·37%) of bivalirudin-assigned patients and 33 (1·10%) of heparin-assigned patients (p=0·0015).

INTERPRETATION

In patients with STEMI undergoing primary PCI predominantly with radial artery access, anticoagulation with bivalirudin plus a post-PCI high-dose infusion for 2-4 h significantly reduced the 30-day composite rate of all-cause mortality or BARC types 3-5 major bleeding compared with heparin monotherapy.

FUNDING

Chinese Society of Cardiology Foundation (CSCF2019A01), and a research grant from Jiangsu Hengrui Pharmaceuticals.

Identification of potential immunomodulators from Pulsatilla decoction that act on therapeutic targets for ulcerative colitis based on pharmacological activity, absorbed ingredients, and in-silico molecular docking

BACKGROUND

Pulsatilla decoction (Bai-Tou-Weng-Tang, BTWT) is a classic formula prescription of a traditional Chinese medicine that is used to treat ulcerative colitis (UC). However, its active components and underlying mechanism of action remain unclear. In the present study, we aimed to identify potential immunomodulators from BTWT that act at therapeutic targets for UC.

METHODS

The protective effects of BTWT granules were examined in mice with colitis induced by dextran sulfate sodium. The absorbed components of BTWT were identified using LC-MS, and selected protein targets of these components in UC were investigated using molecular docking.

RESULTS

Oral administration of BTWT granules significantly alleviated disease severity and colon shortening, and inhibited the inflammatory response in mice with chronic colitis. In these mice, 11 compounds from the BTWT granules were detected in the serum and/or colon. The molecular docking study demonstrated that compounds from Radix pulsatillae, such as anemoside A3, interacted with STAT3 and S1PR1; compounds from Rhizoma coptidis and/or Cortex phellodendri, such as palmatine, interacted with JAK3, PD-1, and PD-L1; and components of Cortex fraxini such as aesculin interacted with S1PR1, JAK3, STAT3 and PD-L1. Further in-vitro experiments showing that the compounds inhibited TNF-α and IL-6 production and STAT3 activation in RAW 264.7 cells suggested that these compounds have immunomodulatory activities.

CONCLUSION

We revealed for the first time that 11 absorbed ingredients from BTWT were immunomodulators against therapeutic targets for UC. These findings suggest that the identified compounds are the active components of BTWT, and the identified protein targets underlie the mechanism of action of BTWT against UC.

Weighted gene co-expression network analysis identifies dysregulated B-cell receptor signaling pathway and novel genes in pulmonary arterial hypertension

Background

Pulmonary arterial hypertension (PAH) is a devastating cardio-pulmonary vascular disease in which chronic elevated pulmonary arterial pressure and pulmonary vascular remodeling lead to right ventricular failure and premature death. However, the exact molecular mechanism causing PAH remains unclear.

Methods

RNA sequencing was used to analyze the transcriptional profiling of controls and rats treated with monocrotaline (MCT) for 1, 2, 3, and 4 weeks. Weighted gene co-expression network analysis (WGCNA) was employed to identify the key modules associated with the severity of PAH. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed to explore the potential biological processes and pathways of key modules. Real-time PCR and western blot analysis were used to validate the gene expression. The hub genes were validated by an independent dataset obtained from the Gene Expression Omnibus database.

Results

A total of 26 gene modules were identified by WGCNA. Of these modules, two modules showed the highest correlation with the severity of PAH and were recognized as the key modules. GO analysis of key modules showed the dysregulated inflammation and immunity, particularly B-cell-mediated humoral immunity in MCT-induced PAH. KEGG pathway analysis showed the significant enrichment of the B-cell receptor signaling pathway in the key modules. Pathview analysis revealed the dysregulation of the B-cell receptor signaling pathway in detail. Moreover, a series of humoral immune response-associated genes, such as BTK, BAFFR, and TNFSF4, were found to be differentially expressed in PAH. Additionally, five genes, including BANK1, FOXF1, TLE1, CLEC4A1, and CLEC4A3, were identified and validated as the hub genes.

Conclusion

This study identified the dysregulated B-cell receptor signaling pathway, as well as novel genes associated with humoral immune response in MCT-induced PAH, thereby providing a novel insight into the molecular mechanisms underlying inflammation and immunity and therapeutic targets for PAH.

Roles of focal adhesion proteins in skeleton and diseases

The skeletal system, which contains bones, joints, tendons, ligaments and other elements, plays a wide variety of roles in body shaping, support and movement, protection of internal organs, production of blood cells and regulation of calcium and phosphate metabolism. The prevalence of skeletal diseases and disorders, such as osteoporosis and bone fracture, osteoarthritis, rheumatoid arthritis, and intervertebral disc degeneration, increases with age, causing pain and loss of mobility and creating a huge social and economic burden globally. Focal adhesions (FAs) are macromolecular assemblies that are composed of the extracellular matrix (ECM), integrins, intracellular cytoskeleton and other proteins, including kindlin, talin, vinculin, paxillin, pinch, Src, focal adhesion kinase (FAK) and integrin-linked protein kinase (ILK) and other proteins. FA acts as a mechanical linkage connecting the ECM and cytoskeleton and plays a key role in mediating cell-environment communications and modulates important processes, such as cell attachment, spreading, migration, differentiation and mechanotransduction, in different cells in skeletal system by impacting distinct outside-in and inside-out signaling pathways. This review aims to integrate the up-to-date knowledge of the roles of FA proteins in the health and disease of skeletal system and focuses on the specific molecular mechanisms and underlying therapeutic targets for skeletal diseases.

Habitual Coffee Consumption Increases Risk of Primary Open-Angle Glaucoma: A Mendelian Randomization Study

PURPOSE

To explore whether there is a causal relationship between coffee consumption and primary open-angle glaucoma (POAG).

DESIGN

Two-sample Mendelian randomization (MR).

PARTICIPANTS

The single-nucleotide polymorphisms (SNPs) associated with coffee consumption (including phenotypes 1 and 2) were selected from a genome-wide association study (GWAS) involving 121 824 individuals of European descent. Coffee intake from the MRC-IEU UK Biobank was also used to identify instruments for coffee intake. Summary-level data for POAG were obtained from the largest publicly available meta-analyses involving 16 677 POAG cases and 199 580 controls of European descent.

METHODS

The inverse variance-weighted (IVW) method was the main MR analysis, whereas weighted-median, weighted mode-based estimate (MBE), MR Pleiotropy RESidual Sum and Outlier (PRESSO) test, and MR-Egger regression were used for sensitivity analysis.

MAIN OUTCOME MEASURES

Diagnosis of POAG.

RESULTS

Three sets of instrumental variables were used to evaluate the causal association between coffee consumption and POAG risk. Results showed that genetically predicted higher coffee consumption phenotype 1 (cups/day) was significantly associated with higher risk of POAG (odds ratio [OR], 1.241; 95% confidence interval [CI], 1.041-1.480; P = 0.016). Genetically predicted higher coffee consumption phenotype 2 (high vs. no/low) was also significantly associated with higher risk of POAG (OR, 1.155; 95% CI, 1.038-1.284; P = 0.008, using the IVW method). Moreover, genetically predicted higher coffee intake from the MRC-IEU UK Biobank OpenGWAS was significantly associated with a higher risk of POAG (OR, 1.727; 95% CI, 1.230-2.425; P = 0.002, using the IVW method). Sensitivity analyses confirmed that the findings were robust to possible pleiotropy.

CONCLUSIONS

These findings provide the genetic evidence that higher coffee consumption is associated with a higher risk of POAG. Given that coffee is widely consumed, our findings provide new insights into potential strategies to prevent and manage POAG.

Novel ATXN1/ATXN1L::NUTM2A fusions identified in aggressive infant sarcomas with gene expression and methylation patterns similar to CIC-rearranged sarcoma

CIC-rearranged sarcomas are newly defined undifferentiated soft tissue tumors with CIC-associated fusions, and dismal prognosis. CIC fusions activate PEA3 family genes, ETV1/4/5, leading to tumorigenesis and progression. We report two high-grade CNS sarcomas of unclear histological diagnosis and one disseminated tumor of unknown origin with novel fusions and similar gene-expression/methylation patterns without CIC rearrangement. All three patients were infants with aggressive diseases, and two experienced rapid disease deterioration and death. Whole-transcriptome sequencing identified an ATXN1-NUTM2A fusion in the two CNS tumors and an ATXN1L-NUTM2A fusion in case 3. ETV1/4/5 and WT1 overexpression were observed in all three cases. Methylation analyses predicted CIC-rearranged sarcoma for all cases. Retrospective IHC staining on case 2 demonstrated ETV4 and WT1 overexpression. ATXN1 and ATXN1L interact with CIC forming a transcription repressor complex. We propose that ATXN1/ATXN1L-associated fusions disrupt their interaction with CIC and decrease the transcription repressor complex, leading to downstream PEA3 family gene overexpression. These three cases with novel ATXN1/ATXN1L-associated fusions and features of CIC-rearranged sarcomas may further expand the scope of "CIC-rearranged" sarcomas to include non-CIC rearrangements. Additional cases are needed to demonstrate if ATXN1/ATXN1L-NUTM2A fusions are associated with younger age and more aggressive diseases.

Causal Associations of Thyroid Function and Age-Related Macular Degeneration: A Two-Sample Mendelian Randomization Study

PURPOSE

To determine whether causal association lies between thyroid function and age-related macular degeneration (AMD) risk in human beings.

DESIGN

Two-sample Mendelian randomization (MR) study.

METHODS

The single-nucleotide polymorphisms associated with free thyroxine (FT4) and thyroid-stimulating hormone (TSH) were selected from a genome-wide association study (GWAS) of 72,167 individuals of European descent. Summary-level data for AMD were obtained from a GWAS published by the International Age-related Macular Degeneration Genomics Consortium of 33,526 individuals (16,144 cases and 17,832 controls). An inverse-variance-weighted (IVW) method was the main MR analysis. Maximum likelihood, weighted median, MR-Egger, MR-pleiotropy residual sum outlier methods were used for the sensitivity analysis.

RESULTS

An increase of 1 SD in genetically predicted FT4 levels was found to be significantly associated with an 18.9 % increase in the overall AMD risk (P = .005). In the multivariable MR analysis controlling for TSH level, the causal effect of FT4 level on the risk of AMD remained (odds ratio [OR] = 1.207, P = .004). A 1-SD increase in TSH levels was nominally associated with a 10.0% decrease in the overall AMD risk (P = .032). After adjusting for FT4 level by multivariable MR analysis, no direct causal relationship was found between TSH level and AMD risk (95% CI = 0.810, 1.125, P = .582).

CONCLUSIONS

Genetic variants predisposing to higher FT4 levels within the normal range were associated with higher AMD risk. Further studies are required to understand the mechanism underlying this putative causal relationship.

Autologous Skin Fibroblast-Based PLGA Nanoparticles for Treating Multiorgan Fibrosis

Fibrotic diseases remain a substantial health burden with few therapeutic approaches. A hallmark of fibrosis is the aberrant activation and accumulation of myofibroblasts, which is caused by excessive profibrotic cytokines. Conventional anticytokine therapies fail to undergo clinical trials, as simply blocking a single or several antifibrotic cytokines cannot abrogate the profibrotic microenvironment. Here, biomimetic nanoparticles based on autologous skin fibroblasts are customized as decoys to neutralize multiple fibroblast-targeted cytokines. By fusing the skin fibroblast membrane onto poly(lactic-co-glycolic) acid cores, these nanoparticles, termed fibroblast membrane-camouflaged nanoparticles (FNPs), are shown to effectively scavenge various profibrotic cytokines, including transforming growth factor-β, interleukin (IL)-11, IL-13, and IL-17, thereby modulating the profibrotic microenvironment. FNPs are sequentially prepared into multiple formulations for different administration routines. As a proof-of-concept, in three independent animal models with various organ fibrosis (lung fibrosis, liver fibrosis, and heart fibrosis), FNPs effectively reduce the accumulation of myofibroblasts, and the formation of fibrotic tissue, concomitantly restoring organ function and indicating that FNPs are a potential broad-spectrum therapy for fibrosis management.

Abstract 5268: The spectrum of FGFR mutations in pediatric and young adult solid tumor

Fibroblast growth factor receptors (FGFRs) are a family of receptor tyrosine kinases expressed on the cell membrane that play crucial roles in cellular lineage commitment, differentiation, proliferation, and apoptosis. Deregulated FGFR signaling is observed in a subset of tumors across various histologies, making FGFRs ideal therapeutic targets. We sought to determine the genetic landscape of FGFR-family variations in a cohort of pediatric and young adult patients with solid tumors. The CHOP Comprehensive Solid Tumor Panel was performed on 1,420 patients. The panel covers 238 cancer genes and screens for single nucleotide variants (SNVs), indels, copy number alterations, and 117 fusion gene partners interrogating over 700 exons for known and novel fusions. Identified variants were categorized and reported according to the AMP/ASCO/CAP guidelines. Fifty-six patients (4.1%), including 47 children and 9 young adults, were found to carry at least one FGFR alteration in their tumors. CNS tumors accounted for most of the cases (51 total, 87.9%), with pilomyxoid astrocytoma/pilocytic astrocytoma and dysembryoplastic neuroepithelial tumor the most common (13 and 12 patients, respectively). Non-CNS solid tumors included rhabdomyosarcoma (4 patients), neuroblastoma/ganglioneuroblastoma (2), and follicular thyroid carcinoma (1). FGFR somatic alterations were found in 56 tumors including 41 SNVs and small indels, 6 internal tandem duplications (ITDs), and 15 fusions genes. The most common SNVs observed were hotspot mutations p.K656E and p.N546K of FGFR1. Sequence alterations in FGFR1 contained 35 SNVs and small indels, mostly gain of function mutations located in the kinase domain, and 6 kinase domain ITDs. One SNV was identified in FGFR2 in the immunoglobulin domain. Two SNVs were reported in FGFR3, both of which were in the fibroblast growth factor receptor family domain, and 3 SNVs were identified in FGFR4, all occurring at the p.V550 codon located on the kinase domain. Companion mutations in non-FGFR genes were detected in 27 tumors, predominantly involving RAS signaling pathway genes including NF1 (14 variants), PIK3CA (8), PTPN11 (6) and PIK3R1 (4). Among fusion variants, FGFR1-TACC1 fusions were found in 5 patients, mostly in pediatric patients. One FGFR3-TACC3 fusion was identified in one young adult patient. Seven pediatric patients tested positive for FGFR2 fusions; all with different 3’ partners. The detection of an FGFR alteration defined or changed the histologic diagnosis for 22 patients. Our results reveal that FGFR alterations account for 4.1% (56/1420) of the patients with solid tumors tested in our laboratory. The majority of the FGFR-positive tumors are low-grade CNS tumors. Further, the identification of FGFR alterations can significantly improve the tumor diagnosis and provide genomic evidence for potential targeted treatment with FGFR inhibitors.

Citation Format: Jinhua Wu, Jeffrey Schubert, Feng Xu, Ariel Long, Maha Patel, Netta Golenberg, Weixuan Fu, Kajia Cao, Jiani Chen, Elizabeth H. Denenberg, Elizabeth A. Fanning, Rochelle Bagatell, Theodore W. Laetsch, Adam Resnick, Mariarita Santi, Phillip Jay B. Storm, Minjie Luo, Lea F. Surrey, Yiming Zhong, Marilyn M. Li. The spectrum of FGFR mutations in pediatric and young adult solid tumor [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5268.

Nangibotide attenuates osteoarthritis by inhibiting osteoblast apoptosis and TGF-β activity in subchondral bone

Osteoarthritis (OA) is a chronic joint disorder that causes cartilage degradation and subchondral bone abnormalities. Nangibotide, also known as LR12, is a dodecapeptide with considerable anti-inflammatory properties, but its significance in OA is uncertain. The aim of the study was to determine whether nangibotide could attenuate the progression of OA, and elucidate the underlying mechanism. In vitro experiments showed that nangibotide strongly inhibited TNF-α-induced osteogenic reduction, significantly enhanced osteoblast proliferation and prevented apoptosis in MC3T3-E1 cells. Male C57BL/6 J mice aged 2 months were randomly allocated to three groups: sham, ACLT, and ACLT with nangibotide therapy. Nangibotide suppressed ACLT-induced cartilage degradation and MMP-13 expression. MicroCT analysis revealed that nangibotide attenuated in vivo subchondral bone loss induced by ACLT. Histomorphometry results showed that nangibotide attenuated ACLT-induced osteoblast inhibition; TUNEL assays and immunohistochemical staining of cleaved-caspase3 further confirmed the in vivo anti-apoptotic effect of nangibotide on osteoblasts. Furthermore, we found that nangibotide exerted protective effects by suppressing TGF-β signaling mediated by Smad2/3 to restore coupled bone remodeling in the subchondral bone. In conclusion, the findings suggest that nangibotide might exert a protective effect on the bone-cartilage unit and maybe an alternative treatment option for OA.

Melanoma differentiation-Associated gene 5 protects against NASH in mice

BACKGROUND AND AIMS

NASH is a complicated disease characterized by hepatocyte steatosis, inflammation infiltration, and liver fibrosis. Accumulating evidence suggests that the innate immunity plays a key role in NASH progression. Here, we aimed to reveal the role of melanoma differentiation-associated gene 5 (MDA5, also known as Ifih1), a conventional innate immune regulator following viral infection, in the progression of NASH and investigate its underlying mechanism.

APPROACH AND RESULTS

We first examined the expression of MDA5 and found that MDA5 was markedly down-regulated in the livers with NASH in human individuals and mice models. MDA5 overexpression significantly inhibits the free fatty acid-induced lipid accumulation and inflammation in hepatocyte in vitro, whereas MDA5 knockdown promotes hepatocyte lipotoxicity. Using hepatocyte-specific Mda5 gene knockout and transgenic mice, we found that diet-induced hepatic steatosis, inflammation, and liver fibrosis were markedly exacerbated by Mda5 deficiency but suppressed by Mda5 overexpression. Mechanistically, we found that the activation of apoptosis signal-regulating kinase 1 (ASK1)-mitogen-activated protein kinase pathway was significantly inhibited by MDA5 but enhanced by MDA5 deletion. We further validated that MDA5 directly interacted with ASK1 and suppressed its N-terminal dimerization. Importantly, blockage of ASK1 with adenovirus-expressing dominant negative ASK1 obviously reversed the lipid accumulation and ASK1 pathway activation when Mda5 was knocked out.

CONCLUSIONS

These data indicate that MDA5 is an essential suppressor in NASH. The findings support MDA5 as a regulator of ASK1 and a promising therapeutic target for NASH.