Identification of an RNA-binding perturbing characteristic for thiopurine drugs and their derivatives to disrupt CELF1-RNA interaction.

RNA-binding proteins (RBPs) are attractive targets in human pathologies. Despite a number of efforts to target RBPs with small molecules, it is still difficult to develop RBP inhibitors, asking for a deeper understanding of how to chemically perturb RNA-binding activity. In this study, we found that the thiopurine drugs (6-mercaptopurine and 6-thioguanine) effectively disrupt CELF1-RNA interaction. The disrupting activity relies on the formation of disulfide bonds between the thiopurine drugs and CELF1. Mutating the cysteine residue proximal to the RNA recognition motifs (RRMs), or adding reducing agents, abolishes the disrupting activity. Furthermore, the 1,2,4-triazole-3-thione, a thiopurine analogue, was identified with 20-fold higher disrupting activity. Based on this analogue, we found that compound 9 disrupts CELF1-RNA interaction in living cells and ameliorates CELF1-mediated myogenesis deficiency. In summary, we identified a thiol-mediated binding mechanism for thiopurine drugs and their derivatives to perturb protein-RNA interaction, which provides novel insight for developing RBP inhibitors. Additionally, this work may benefit the pharmacological and toxicity research of thiopurine drugs.

Mitochondrial folate metabolism-mediated α-linolenic acid exhaustion masks liver fibrosis resolution.

Sustainable TGF-ß1 signaling drives organ fibrogenesis. However, the cellular adaptation to maintain TGF-ß1 signaling remains unclear. In this study, we revealed that dietary folate restriction promoted the resolution of liver fibrosis in mice with nonalcoholic steatohepatitis. In activated hepatic stellate cells, folate shifted toward mitochondrial metabolism to sustain TGF-ß1 signaling. Mechanistically, nontargeted metabolomics screening identified that α-linolenic acid (ALA) is exhausted by mitochondrial folate metabolism in activated hepatic stellate cells. Knocking down serine hydroxymethyltransferase 2 increases the bioconversion of ALA to docosahexaenoic acid, which inhibits TGF-ß1 signaling. Finally, blocking mitochondrial folate metabolism promoted liver fibrosis resolution in nonalcoholic steatohepatitis mice. In conclusion, mitochondrial folate metabolism/ALA exhaustion/TGF-ßR1 reproduction is a feedforward signaling to sustain profibrotic TGF-ß1 signaling, and targeting mitochondrial folate metabolism is a promising strategy to enforce liver fibrosis resolution.

Inhibiting cholesterol de novo synthesis promotes hepatocellular carcinoma progression by upregulating prostaglandin E synthase 2-mediated arachidonic acid metabolism under high fatty acid conditions.

Inhibition of cholesterol de novo synthesis (DNS) by statins has controversial effects on the treatment of hepatocellular carcinoma (HCC). High fatty acid conditions have been reported to limit the effect of statins on metabolism diseases. Whether high fatty acid conditions interfere with the effect of statins on HCC remains unclear. Here, we reported that inhibiting cholesterol DNS with atorvastatin promoted the oncogenic capabilities of diethylnitrosamine (DEN) in mice fed high fatty acid diets (HFD). The combined analysis of metabolomics and transcriptomics revealed that arachidonic acid (AA) metabolism was the most significant changed pathway between mice with and without atorvastatin treatment. In vitro, in the presence of AA precursor linoleic acid (LA), atorvastatin promoted the proliferation and migration ability of HCC cell lines. However, in the absence of LA, these phenomena disappeared. TCGA and tissue microarray examination revealed that prostaglandin e synthase 2 (PTGES2), a key enzyme in AA metabolism, was associated with the poor outcome of HCC patients. Overexpression of PTGES2 promoted the proliferation and migration of HCC cell lines, and knockdown of PTGES2 inhibited the proliferation and migration of cells. Additionally, atorvastatin upregulated PTGES2 expression by enhancing Sterol-regulatory element binding protein 2 (SREBP2)-mediated transcription. Knockdown of PTGES2 reversed the proliferation and migration ability enhanced by atorvastatin. Overall, our study reveals that a high fatty acid background is one of the possible conditions limiting the application of statins in HCC, under which statins promote the progression of HCC by enhancing SREBP2-mediated PTGES2 transcription.

N-glycosylation of SCAP exacerbates hepatocellular inflammation and lipid accumulation via ACSS2-mediated histone H3K27 acetylation.

Sterol regulatory element binding protein (SREBP) cleavage-activating protein (SCAP) is a widely expressed membrane glycoprotein that acts as an important modulator of lipid metabolism and inflammatory stress. N-glycosylation of SCAP has been suggested to modulate cancer development, but its role in nonalcoholic steatohepatitis (NASH) is poorly understood. In this study, the N-glycosylation of SCAP was analyzed by using sequential trypsin proteolysis and glycosidase treatment. The liver cell lines expressing wild-type and N-glycosylation sites mutated SCAP were constructed to investigate the N-glycosylation role of SCAP in regulating inflammation and lipid accumulation as well as the underlying mechanisms. The hepatic SCAP protein levels were significantly increased in C57BL/6J mice fed with Western diet and sugar water (WD + SW) and diabetic db/db mice, which exhibited typical liver steatosis and inflammation accompanied with hyperglycemia. In vitro, the enhanced N-glycosylation by high glucose increased the protein stability of SCAP and hence increased its total protein levels, whereas the ablation of N-glycosylation significantly decreased SCAP protein stability and alleviated lipid accumulation and inflammation in hepatic cell lines. Mechanistically, SCAP N-glycosylation increased not only the SREBP-1-mediated acetyl-CoA synthetase 2 (ACSS2) transcription but also the AMPK-mediated S659 phosphorylation of ACCS2 protein, causing the enhanced ACSS2 levels in nucleus and hence increasing the histone H3K27 acetylation (H3K27ac), which is a key epigenetic modification associated with NASH. Modulating ACSS2 expression or its location in the nuclear abolished the effects of SCAP N-glycosylation on H3K27ac and lipid accumulation and inflammation. In conclusion, SCAP N-glycosylation aggravates inflammation and lipid accumulation through enhancing ACSS2-mediated H3K27ac in hepatocytes.NEW & NOTEWORTHY N-glycosylation of SCAP exacerbates inflammation and lipid accumulation in hepatocytes through ACSS2-mediated H3K27ac. Our data suggest that SCAP N-glycosylation plays a key role in regulating histone H3K27 acetylation and targeting SCAP N-glycosylation may be a new strategy for treating nonalcoholic steatohepatitis (NASH).

Antibiotic-induced gut microbiota disruption promotes vascular calcification by reducing short-chain fatty acid acetate.

BACKGROUND: Vascular calcification is a common vascular lesion associated with high morbidity and mortality from cardiovascular events. Antibiotics can disrupt the gut microbiota (GM) and have been shown to exacerbate or attenuate several human diseases. However, whether antibiotic-induced GM disruption affects vascular calcification remains unclear. METHODS: Antibiotic cocktail (ABX) treatment was utilized to test the potential effects of antibiotics on vascular calcification. The effects of antibiotics on GM and serum short-chain fatty acids (SCFAs) in vascular calcification mice were analyzed using 16 S rRNA gene sequencing and targeted metabolomics, respectively. Further, the effects of acetate, propionate and butyrate on vascular calcification were evaluated. Finally, the potential mechanism by which acetate inhibits osteogenic transformation of VSMCs was explored by proteomics. RESULTS: ABX and vancomycin exacerbated vascular calcification. 16 S rRNA gene sequencing and targeted metabolomics analyses showed that ABX and vancomycin treatments resulted in decreased abundance of Bacteroidetes in the fecal microbiota of the mice and decreased serum levels of SCFAs. In addition, supplementation with acetate was found to reduce calcium salt deposition in the aorta of mice and inhibit osteogenic transformation in VSMCs. Finally, using proteomics, we found that the inhibition of osteogenic transformation of VSMCs by acetate may be related to glutathione metabolism and ubiquitin-mediated proteolysis. After adding the glutathione inhibitor Buthionine sulfoximine (BSO) and the ubiquitination inhibitor MG132, we found that the inhibitory effect of acetate on VSMC osteogenic differentiation was weakened by the intervention of BSO, but MG132 had no effect. CONCLUSION: ABX exacerbates vascular calcification, possibly by depleting the abundance of Bacteroidetes and SCFAs in the intestine. Supplementation with acetate has the potential to alleviate vascular calcification, which may be an important target for future treatment of vascular calcification.

Biocontrol potential and growth-promoting effect of endophytic fungus Talaromyces muroii SD1-4 against potato leaf spot disease caused by Alternaria alternata.

BACKGROUND: Alternaria alternata is the primary pathogen of potato leaf spot disease, resulting in significant potato yield losses globally. Endophytic microorganism-based biological control, especially using microorganisms from host plants, has emerged as a promising and eco-friendly approach for managing plant diseases. Therefore, this study aimed to isolate, identify and characterize the endophytic fungi from healthy potato leaves which had great antifungal activity to the potato leaf spot pathogen of A. alternata in vitro and in vivo. RESULTS: An endophytic fungal strain SD1-4 was isolated from healthy potato leaves and was identified as Talaromyces muroii through morphological and sequencing analysis. The strain SD1-4 exhibited potent antifungal activity against the potato leaf spot pathogen A. alternata Lill, with a hyphal inhibition rate of 69.19%. Microscopic and scanning electron microscope observations revealed that the strain SD1-4 grew parallel to, coiled around, shrunk and deformed the mycelia of A. alternata Lill. Additionally, the enzyme activities of chitinase and ß-1, 3-glucanase significantly increased in the hyphae of A. alternata Lill when co-cultured with the strain SD1-4, indicating severe impairment of the cell wall function of A. alternata Lill. Furthermore, the mycelial growth and conidial germination of A. alternata Lill were significantly suppressed by the aseptic filtrate of the strain SD1-4, with inhibition rates of 79.00% and 80.67%, respectively. Decrease of leaf spot disease index from 78.36 to 37.03 was also observed in potato plants treated with the strain SD1-4, along with the significantly increased plant growth characters including plant height, root length, fresh weight, dry weight, chlorophyll content and photosynthetic rate of potato seedlings. CONCLUSION: The endophyte fungus of T. muroii SD1-4 isolated from healthy potato leaves in the present study showed high biocontrol potential against potato leaf spot disease caused by A. alternata via direct parasitism or antifungal metabolites, and had positive roles in promoting potato plant growth.

Pseudomonas syringae pv. actinidiae Unique Effector HopZ5 Interacts with GF14C to Trigger Plant Immunity.

The bacterial canker of kiwifruit caused by Pseudomonas syringae pv. actinidiae (Psa) is the most devastating disease threatening the global kiwifruit production. This pathogen delivers multiple effector proteins into plant cells to resist plant immune responses and facilitate their survival. Here, we focused on the unique effector HopZ5 in Psa, which previously has been reported to have virulence functions. In this study, our results showed that HopZ5 could cause macroscopic cell death and trigger a serious immune response by agroinfiltration in Nicotiana benthamiana, along with upregulated expression of immunity-related genes and significant accumulation of reactive oxygen species and callose. Subsequently, we confirmed that HopZ5 interacted with the phosphoserine-binding protein GF14C in both the nonhost plant N. benthamiana (NbGF14C) and the host plant kiwifruit (AcGF14C), and silencing of NbGF14C compromised HopZ5-mediated cell death, suggesting that GF14C plays a crucial role in the detection of HopZ5. Further studies showed that overexpression of NbGF14C both markedly reduced the infection of Sclerotinia sclerotiorum and Phytophthora capsica in N. benthamiana, and overexpression of AcGF14C significantly enhanced the resistance of kiwifruit against Psa, indicating that GF14C positively regulates plant immunity. Collectively, our results revealed that the virulence effector HopZ5 could be recognized by plants and interact with GF14C to activate plant immunity.

Attenuation of osteoarthritis progression via locoregional delivery of Klotho-expressing plasmid DNA and Tanshinon IIA through a stem cell-homing hydrogel.

BACKGROUND: Osteoarthritis (OA) is an aging-related degenerative joint disorder marked by joint discomfort and rigidity. Senescent chondrocytes release pro-inflammatory cytokines and extracellular matrix-degrading proteins, creating an inflammatory microenvironment that hinders chondrogenesis and accelerates matrix degradation. Targeting of senescent chondrocytes may be a promising approach for the treatment of OA. Herein, we describe the engineering of an injectable peptide-hydrogel conjugating a stem cell-homing peptide PFSSTKT for carrying plasmid DNA-laden nanoparticles and Tanshinon IIA (pPNP + TIIA@PFS) that was designed to attenuate OA progression by improving the senescent microenvironment and fostering cartilage regeneration. RESULTS: Specifically, pPNP + TIIA@PFS elevates the concentration of the anti-aging protein Klotho and blocks the transmission of senescence signals to adjacent healthy chondrocytes, significantly mitigating chondrocyte senescence and enhancing cartilage integrity. Additionally, pPNP + TIIA@PFS recruit bone mesenchymal stem cells and directs their subsequent differentiation into chondrocytes, achieving satisfactory chondrogenesis. In surgically induced OA model rats, the application of pPNP + TIIA@PFS results in reduced osteophyte formation and attenuation of articular cartilage degeneration. CONCLUSIONS: Overall, this study introduces a novel approach for the alleviation of OA progression, offering a foundation for potential clinical translation in OA therapy.

An Adhesive Bioink toward Biofabrication under Wet Conditions.

Three-dimensional (3D) bioprinting is driving significant innovations in biomedicine over recent years. Under certain scenarios such as in intraoperative bioprinting, the bioinks used should exhibit not only cyto/biocompatibility but also adhesiveness in wet conditions. Herein, an adhesive bioink composed of gelatin methacryloyl, gelatin, methacrylated hyaluronic acid, and skin secretion of Andrias davidianus is designed. The bioink exhibits favorable cohesion to allow faithful extrusion bioprinting in wet conditions, while simultaneously showing good adhesion to a variety of surfaces of different chemical properties, possibly achieved through the diverse bonds presented in the bioink formulation. As such, this bioink is able to fabricate sophisticated planar and volumetric constructs using extrusion bioprinting, where the dexterity is further enhanced using ergonomic handheld bioprinters to realize in situ bioprinting. In vitro experiments reveal that cells maintain high viability; further in vivo studies demonstrate good integration and immediate injury sealing. The characteristics of the bioink indicate its potential widespread utility in extrusion bioprinting and will likely broaden the applications of bioprinting toward situations such as in situ dressing and minimally invasive tissue regeneration.

Protein Kinase C Is Involved in Vegetative Development, Stress Response and Pathogenicity in Verticillium dahliae.

Potato Verticillium wilt, caused by Verticillium dahliae, is a serious soil-borne vascular disease, which restricts the sustainable development of the potato industry, and the pathogenic mechanism of the fungus is complex. Therefore, it is of great significance to explore the important pathogenic factors of V. dahliae to expand the understanding of its pathology. Protein kinase C (PKC) gene is located in the Ca2+ signaling pathway, which is highly conserved in filamentous fungi and involved in the regulation of a variety of biological processes. In the current study, the PKC gene in V. dahliae (VdPKC) was characterized, and its effects on the fungal pathogenicity and tolerance to fungicide stress were further studied. The results showed that the VdPKC positively regulated the growth and development, conidial germination, and production of V. dahliae, which was necessary for the fungus to achieve pathogenicity. It also affected the formation of melanin and microsclerotia and changed the adaptability of V. dahliae to different environmental stresses. In addition, VdPKC altered the tolerance of V. dahliae to different fungicides, which may be a potential target for polyoxin. Therefore, our results strongly suggest that VdPKC gene is necessary for the vegetative growth, stress response, and pathogenicity of V. dahliae.

Hypothetical Protein VDAG_07742 Is Required for Verticillium dahliae Pathogenicity in Potato.

Verticillium dahliae is a soil-borne pathogenic fungus that causes Verticillium wilt in host plants, a particularly serious problem in potato cultivation. Several pathogenicity-related proteins play important roles in the host infection process, hence, identifying such proteins, especially those with unknown functions, will surely aid in understanding the mechanism responsible for the pathogenesis of the fungus. Here, tandem mass tag (TMT) was used to quantitatively analyze the differentially expressed proteins in V. dahliae during the infection of the susceptible potato cultivar "Favorita". Potato seedlings were infected with V. dahliae and incubated for 36 h, after which 181 proteins were found to be significantly upregulated. Gene ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses showed that most of these proteins were involved in early growth and cell wall degradation. The hypothetical, secretory protein with an unknown function, VDAG_07742, was significantly upregulated during infection. The functional analysis with knockout and complementation mutants revealed that the associated gene was not involved in mycelial growth, conidial production, or germination; however, the penetration ability and pathogenicity of VDAG_07742 deletion mutants were significantly reduced. Therefore, our results strongly indicate that VDAG_07742 is essential in the early stage of potato infection by V. dahliae.

Extracellular vesicle miR-32 derived from macrophage promotes arterial calcification in mice with type 2 diabetes via inhibiting VSMC autophagy.

BACKGROUND: The development of diabetes vascular calcification (VC) is tightly associated with the inhibition of vascular smooth muscle cell (VSMC) autophagy. Previously, our team found that miR-32-5p (miR-32) promotes macrophage activation, and miR-32 is expressed at higher level in the plasma of patients with coronary calcification. However, whether miR-32 mediates the function of macrophages in type 2 diabetes (T2D) VC is still unclear. METHODS: Wild-type (WT) and miR-32-/- mice were used in this study. qRT-PCR and western blotting were used to analyze gene expression. Flow cytometry was used to analyze the influence of glucose concentration on macrophage polarization. Nanoparticle tracking analysis (NTA), transmission electron microscopy, and confocal microscopy were used to identify macrophage extracellular vehicles (EVs). Immunofluorescence, in situ hybridization (ISH), immunohistochemistry, and alizarin red staining were used to analyze the influence of macrophage EVs on autophagy and calcification of the aorta of miR-32-/- mice. A luciferase assay was used to analyze the effect of miR-32 on myocyte enhancer factor 2D (Mef2d) expression. Co-IP combined with mass spectrometry (MS) and transcriptome sequencing was used to analyze the signalling pathway by which Mef2d acts in VSMC autophagy. RESULTS: We found that high glucose conditions upregulate miR-32 expression in macrophages and their EVs. Importantly, macrophages and their EVs promote VSMC osteogenic differentiation and upregulate miR-32 expression in VSMCs. Moreover, miR-32 mimics transfection promoted osteogenic differentiation and inhibited autophagy in VSMCs. In vitro and in vivo experiments showed that Mef2d is the key target gene of miR-32 that inhibits VSMC autophagy. Furthermore, MS and transcriptome sequencing found that cGMP-PKG is an important signalling pathway by which Mef2d regulates VSMC autophagy. In addition, after T2D miR-32-/- mice were injected with macrophage EVs via the caudal vein, miR-32 was detected in aortic VSMCs of miR-32-/- mice. Moreover, autophagy was significantly inhibited, and calcification was significantly enhanced in aorta cells. CONCLUSIONS: These results reveal that EVs are the key pathway by which macrophages promote T2D VC, and that EVs miR-32 is a key cause of autophagy inhibition in VSMCs.

Identification of Genetic and Chemical Factors Affecting Type III Secretion System Expression in Pseudomonas syringae pv. actinidiae Biovar 3 Using a Luciferase Reporter Construct.

The type III secretion system (T3SS) is a key factor in the pathogenesis of Pseudomonas syringae pv. actinidiae biovar 3 (Psa3), the causal agent of a global kiwifruit bacterial canker pandemic. To monitor the T3SS expression levels in Psa3, we constructed a luciferase reporter plasmid-expressing HrpAPsa3-NLuc fusion protein. The expression of HrpA-NLuc was induced in hrp-inducing conditions whereas the level of luciferase activity correlated with the expression of hrp/hrc genes in Psa3 confirmed the reliability of the reporter construct. Based on the readout of the NLuc reporter construct, three small molecule compounds 4-methoxy-cinnamic acid, sulforaphane, and ferulic acid were determined as T3SS inhibitors in Psa3, whereas sodium acetate was determined to be a T3SS inducer. Moreover, the aqueous extract of fruit inhibited the accumulation of HrpA-NLuc in Psa3 in medium and in planta. Additionally, the T3SS inhibitors suppress Psa3 virulence, whereas the T3SS inducer promotes Psa3 virulence on kiwifruit. Thus, our findings may provide clues to why the fruit is not infected by Psa3, and the Psa3 T3SS inhibitors have potential as alternatives to current nonspecific antimicrobials for disease management.

Identification and first report of Colletotrichum fructicola causing fruit rot on Zizyphus mauritiana in China.

Because of its high economic value and potential for adaptation to subtropical climates, Indian jujube (Zizyphus mauritiana Lam.) is one of the most important fruit crops introduced into south of Guizhou Province, China. In December 2020, approximately 10 to 15% of the harvested jujube (Z. mauritiana Lam. Wuqian) showed fruit rot symptoms after storage at 4°C for 10-15 days in Luodian county (25°34'N, 106°82'E). Symptoms of brown, circular, watery lesions were observed on the jujube fruits. Small pieces (c.a. 5 mm) at the margins of rot tissue were incubated on PDA plates at 25°C in darkness after surface sterilization in 1.5% NaClO for 45 s followed with triple washes using sterile distilled water. Two monoconidial isolates were obtained after incubation and identical colony morphologies were observed with olive grey, cottony aerial mycelium which became darker after 10 days growth. The colony reverse began white but turned brown with age. Conidia, produced in orange masses, were mainly cylindrical with the size of 9.2-16.8 µm (average 13.7 µm) × 3.8-6.2 µm (average 4.6 µm) (n = 50), typical of Colletotrichum spp. (Vieira et al. 2014). For further identification, DNA of these two isolates were extracted and were used for multi-locus genotyping. Five loci, including the ITS region, partial sequences of glyceraldehyde-3-phosphate dehydrogenase (GAPDH), actin (ACT), ß-tubulin (BTU) and chitin synthase (CHS) genes, were amplified and sequenced with primers of ITS1/ITS4, GDF1/GDR1, ACT512F/ ACT783R, Bt2a/Bt2b and CHS79F/CHS354R, respectively. No differences was found between the isolates at any of the loci and one sequence for each locus was deposited in the Genebank database under accessions OL376803, OL404925, OL404926, OL404927 and OL404928, respectively. Blastn results indicated that the ITS, GAPDH, ACT, BTU and CHS sequences of the jujube isolates shared 100%, 98.56%, 96.62%, 99.48% and 99.33% similarity with those of ex-type strain ICMP 18581 of C. fructicola (GenBank Accession Nos. JX010165, JX010033, JX009501, JX010405 and JX009866). Phylogenetic analysis including published ITS, GAPDH, ACT, BTU and CHS data for C. fructicola and other Colletotrichum species was performed using MEGA 6.0. Based on morphological and molecular data, the jujube isolates were identified as C. fructicola. Pathogenicity was determined for both isolates on jujube fruits cultivar "Wuqian". Fruit surface was sterilized with 75% ethanol, air dried, and wounded with a needle by piercing into 2 mm depth. Ten microliters of a spore suspension (1 × 106 spores/ml) or sterilized water were applied to one of two wounds on the same fruit. There were six replicate inoculations for each isolate and the whole experiment was repeated twice. Treated fruit were maintained in a growth chamber with 80% relative humidity at 25°C. Symptoms of fruit rots, identical the original observations, developed around the infection sites at 3 days post inoculation. These began as light brown, circular lesions, which got darker with orange spore masses after 7 days and both isolates caused identical symptoms. However, the wounds inoculated with water remained asymptomatic. C. fructicola was successfully reisolated from the infected areas to fulfill Koch's postulates. To the best of our knowledge, this is the first report of jujube fruit rot caused by C. fructicola in China, which may become an emerging problem considering the area expansion of Z. mauritiana cultivation and transportation of its fruit. Funding: Funding was provided by Science and Technology Foundation of Guizhou Province (Guizhou Science Base [2020]1Y104), Talent Development Program of Guizhou Province (Qian Jiaohe KY [2021]080), Innovation and Entrepreneurship Training Program of Guizhou University (Guo Chuangzi [2020]017). Reference: (1) Vieira, W., et al. 2014. Fungal Divers. 67(1): 181-202.

The OmpR-like Transcription Factor as a Negative Regulator of hrpR/S in Pseudomonas syringae pv. actinidiae.

Bacterial canker of kiwifruit is a devastating disease caused by Pseudomonas syringae pv. actinidiae (Psa). The type III secretion system (T3SS), which translocates effectors into plant cells to subvert plant immunity and promote extracellular bacterial growth, is required for Psa virulence. Despite that the "HrpR/S-HrpL" cascade that sophisticatedly regulates the expression of T3SS and effectors has been well documented, the transcriptional regulators of hrpR/S remain to be determined. In this study, the OmpR-like transcription factor, previously identified by DNA pull-down assay, was found to be involved in the regulation of hrpR/S genes, and its regulatory mechanisms and other functions in Psa were explored through techniques including gene knockout and overexpression, ChIP-seq, and RNA-seq. The OmpR-like transcription factor had binding sites in the promoter region of the hrpR/S, and the transcriptional level of the hrpR/S increased after the deletion of OmpR-like and decreased upon its overexpression in an OmpR-like deletion background. Additionally, OmpR-like overexpression reduced the strain's capacity to form biofilms and lipopolysaccharides, led to its slow growth in King's B medium, and reduced its swimming ability, although there was no significant effect on its pathogenicity against kiwifruit hosts. Our results indicated that OmpR-like directly and negatively regulates the transcription of hrpR/S and may be involved in the regulation of multiple biological processes in Psa. Our results provide a basis for further understanding the transcriptional regulation mechanism of hrpR/S in Psa.

Magic and mystery of microRNA-32.

MicroRNAs (miRNAs) are a group of endogenous, small (∼22 nts in length) noncoding RNA molecules that function specifically by base pairing with the mRNA of genes and regulate gene expression at the post-transcriptional level. Alterations in miR-32 expression have been found in numerous diseases and shown to play a vital role in cell proliferation, apoptosis, oncogenesis, invasion, metastasis and drug resistance. MiR-32 has been documented as an oncomiR in the majority of related studies but has been also verified as a tumour suppressor miRNA in conflicting reports. Moreover, it has a crucial role in metabolic and cardiovascular disorders. This review provides an in-depth look into the most recent finding regarding miR-32, which is involved in the expression, regulation and functions in different diseases, especially tumours. Additionally, this review outlines novel findings suggesting that miR-32 may be useful as a noninvasive biomarker and as a targeted therapeutic in several diseases.

Lightweight, Fire-Retardant, and Anti-Compressed Honeycombed-Like Carbon Aerogels for Thermal Management and High-Efficiency Electromagnetic Absorbing Properties.

Ordered porous carbon materials (PCMs) have potential applications in various fields due to their low mass densities and porous features. However, it yet remains extremely challenging to construct PCMs with multifunctionalization for electromagnetic wave absorption. Herein, the honeycombed-like carbon aerogels with embedded Co@C nanoparticles are fabricated by a directionally freeze-casting and carbonization method. The optimized aerogel possesses low density (0.017 g cm-3 ), fire-retardant, robust mechanical performance (compression moduli reach 1411 and 420 kPa in the longitudinal and transverse directions at 80% strain, respectively), and high thermal management (high thermal insulation capability and high-efficiency electrothermal conversion ability). Notably, the optimized aerogel exhibits the excellent electromagnetic wave absorption properties with broad effective absorption bandwidth (13.12-17.14 GHz) and strong absorption (-45.02 dB) at a thickness of only 1.5 mm. Density functional theory calculations and the experimental results demonstrate that the excellent electromagnetic wave absorption properties stem from the synergetic effects among high electrical conductivity, numerous interfaces and dipoles and unique ordered porous structure. Meanwhile, the computer simulation technology (CST) simulation confirms that the multifunctional aerogel can attenuate more electromagnetic energy in a practical environment. This work paves the way for rational design and fabrication of the next-generation electromagnetic wave absorbing materials.

Cholesterol impairs hepatocyte lysosomal function causing M1 polarization of macrophages via exosomal miR-122-5p.

Nonalcoholic steatohepatitis (NASH) is a major threat to health worldwide. Lipotoxicity and macrophage-mediated inflammation play key roles in the pathogenesis of NASH. In this study, we found that individuals with higher serum LDL-C levels have a higher prevalence of nonalcoholic fatty liver disease (NAFLD) and elevated levels of glutamic-pyruvic transaminase, glutamic-oxalacetic transaminase and alkaline phosphatase. A logistic regression analysis revealed that serum LDL-C level is an independent risk factor for the prevalence and prognosis of NAFLD. In vitro, we used ox-LDL and MßCD-cholesterol to treat Huh7 cells and found that cholesterol loading reduced lysosomal quantity and impaired lysosomal acidification, reducing the number of multivesicular bodies (MVBs) colocalizing with lysosomes. The bafilomycin A1 inhibition of lysosomal function also inhibited lysosomal MVBs degradation, promoting the release of exosomes from the Huh7 cells. Next, we found that cholesterol loading promoted exosome release from the Huh7 cells. The exosomes from the cholesterol-loaded cells increased the ratio of the THP-1 cells positive for the M1 marker (iNOS-1) without affecting the ratio of the cells positive for the M2 marker (CD206). Moreover, an elevated level of miR-122-5p was observed in exosomes derived from the Huh7 cells loaded with cholesterol. While the miR-122-5p mimics promoted THP-1 M1 polarization, downregulating miR-122-5p in the Huh7 cells inhibited the exosome-induced activation of macrophages and macrophage-related inflammation. These findings suggest that cholesterol plays an important role in the development and progression of NASH. Cholesterol-induced lysosomal dysfunction increases exosome release from hepatocytes, resulting in M1 polarization and macrophage-induced inflammation in a miR-122-5p-dependent manner.

A novel secretagogin/ATF4 pathway is involved in oxidized LDL-induced endoplasmic reticulum stress and islet ß-cell apoptosis.

Excessive accumulation of cholesterol in ß cells initiates endoplasmic reticulum (ER) stress and associated apoptosis. We have reported that excessive uptake of cholesterol by MIN6 cells decreases the expression of secretagogin (SCGN) and then attenuates insulin secretion. Here, we aimed to determine whether cholesterol-induced SCGN decrease is involved in the modulation of ER stress and apoptosis in pancreatic ß cells. In this study, MIN6 cells were treated with oxidized low-density lipoprotein (ox-LDL) for 24 h, and then intracellular lipid droplets and cell apoptosis were quantified, and SCGN and ER stress markers were identified by western blot analysis. Furthermore, small interfer RNA (siRNA)-mediated SCGN knockdown and recombinant plasmid-mediated SCGN restoration experiments were performed to confirm the role of SCGN in ER stress and associated cell apoptosis. Finally, the interaction of SCGN with ATF4 was computationally predicted and then validated by a co-immunoprecipitation assay. We found that ox-LDL treatment increased the levels of ER stress markers, such as phosphorylated protein kinase-like endoplasmic reticulum kinase, phosphorylated eukaryotic initiation factor 2 alpha, activating transcription factor 4 (ATF4), and transcription factor CCAAT-enhancer-binding protein homologous protein, and promoted MIN6 cell apoptosis; in addition, the expression of SCGN was downregulated. siRNA-mediated SCGN knockdown exacerbated ß-cell ER stress by increasing ATF4 expression. Pretreatment of MIN6 cells with the recombinant SCGN partly antagonized ox-LDL-induced ER stress and apoptosis. Furthermore, a co-immunoprecipitation assay revealed an interaction between SCGN and ATF4 in MIN6 cells. Taken together, these results demonstrated that pancreatic ß-cell apoptosis induced by ox-LDL treatment can be attributed, in part, to an SCGN/ATF4-dependent ER stress response.

First Report of Fruit Blotch on Plum caused by Fusarium fujikuroi in China.

Plum is commercially cultivated worldwide for the rich nutrient in its fruit. In May 2019, plum with symptoms of fruit rot were collected from fields located in Liuma town, Guizhou Province, China. The incidence of the disease varied from 10 to 20%, which was observed in 15 plum orchards (18 hectares) surveyed. Estimated yield loss was~5 to 10% for each field. Diseased fruits showed deformity, wilting and sunken lesions, and subsequenly became melanized and rotted. Diseased tissues were surface disinfected with 70% ethanol for 45 s and rinsed with sterile distilled water three times. Four morphologically similar colonies with white fluffy aerial mycelium and a reddish pigment were obtained after 3 days incubation on potato dextrose agar (PDA) at 25°C. Four single-spore isolates produced conidia with 1 to 2 septa that were sickle-shaped, thin-walled with a tapering and curved apical cell, measuring 15.6 to 29.6 × 4.8 to 8.7 µm (average 19.5×5.9 µm, n=50). Based on the cultural and conidial morphology, the isolates were identified as Fusarium (Mun et al. 2012; Leslie and Summerell 2006). DNA of two isolates was extracted using the Ezup Column Fungal Genomic DNA Extraction Kit (Sangon Bioengineering Shanghai, LTD.). To confirm the morphological diagnosis, DNA sequence data from three loci were obtained. PCR amplification was carried out with universal primers ITS1/ITS4 (White et al. 1990), translation elongation factor (EF-1α), EF1-H (5'-ATGGGTAAGGAAGACAAGAC-3') and EF2-T (5'-GGAAGTACCAGTGATCATGTT-3') (O'Donnell et al. 1998) and the second largest subunit of RNA polymerase II (RPB2), 5F2(5'-GGGGWGAYCAGAAGAAGGC-3') and 7cR (5'-CCCATRGCTTGYTTRCCCAT-3') (O'Donnell et al. 2007). Primers ITS1 and ITS4 produced a 559-bp amplicon (GenBank accession. MW085028). BLAST analysis showed 100% sequence identity to sequences of several species, deposited in GenBank, including F. fujikuroi. The EF-1α sequence (MW086868) was 100% identical to that of Fusarium fujikuroi (MN193860.1). The RPB2 primers amplified a fragment (MW086869) that was 99.9% identical to that of F. fujikuroi (MN193888.1). The BLASTn results based on the partial EF-1α and RPB2 sequences suggest isolate HJGF1 is F. fujikuroi. A pathogenicity assay was conducted using an agar disk inoculation method on plum. Fruits were stab inoculated with HJGF1 by piercing 1-mm at 3 points using a sterile needle, and fruits were mock inoculated with sterile PDA, each fruit was inoculated with three disks. (Fig. 1). The treated fruit were maintained in a growth chamber with 90% relative humidity at 25°C, and a daily 12-h photoperiod. After 5 days, the artificially inoculated fruit showed blotches with sunken lesions similar to those observed in the orchards, whereas no symptoms were observed on the control fruit. The experiment was repeated twice with similar results. F. fujikuroi was reisolated from infected tissues and confirmed by sequence analysis. To our knowledge, this is the first report of F. fujikuroi causing fruit blotch of plum in China. Considering the economic importance of plum in China and throughout the world, F. fujikuroi may be an emerging problem for plum cultivation. Thus, further study of fruit blotch of plum is warranted.