A Novel TrxR1 Inhibitor Regulates NK and CD8+ T Cell Infiltration and Cytotoxicity, Enhancing the Efficacy of Anti-PD-1 Immunotherapy against Hepatocarcinoma.

Hepatocellular carcinoma (HCC) has the third highest cancer-related mortality rate globally. The immunosuppressive microenvironment of HCC limits effective treatment options. HCC cells and associated microenvironmental factors suppress NK and T cell infiltration and cytotoxic activities. The abnormal number or function of NK and T cells leads to a lack of immune surveillance. Recently, immunotherapy targeting PD-1 and PD-L1 has been shown to activate functionally exhausted cytotoxic immune cells in some solid tumors. However, the response rate and therapeutic efficacy against solid tumors with little lymphocyte infiltration are limited, especially for HCC. Therefore, new targets and therapeutics that induce tumor cell apoptosis and overcome the problem of depletion of immune cells, thereby inhibiting the immune escape of HCC cells, are urgently required. Butaselen (2-bis[2-(1,2-benzisothiazol-2(2H)-ketone)]butane), an organic molecule containing selenium, is a new type of thioredoxin reductase inhibitor. In this study, we found that butaselen promoted NK and T cell activity and infiltration in the tumor microenvironment in HCC-bearing mice by enhancing the expression of CXCR3, NKG2D, and their respective ligands. When used alone, it can significantly inhibit tumor growth and exert a synergistic effect in combination with PD-1 blockade. We suggested the role of the thioredoxin reductase system in the regulation of the tumor immunosuppressive microenvironment and developed a new effective therapeutic molecule for HCC, revealing the mechanism of butaselen in inhibiting tumor cell immune escape.

Complete genome sequence of polygonatum kingianum mottle virus infecting Polygonatum kingianum Coll. et Hemsl in Yunnan, China.

The complete genome sequence of a putative novel potyvirus, tentatively named "polygonatum kingianum mottle virus" (PKgMV; GenBank accession no. ON428226), infecting Polygonatum kingianum in China, was obtained by next-generation sequencing (NGS), reverse transcription polymerase chain reaction (RT-PCR), and rapid amplification of cDNA ends (RACE). PKgMV exhibits the typical genome organization and characteristics of members of the genus Potyvirus, with a length of 10,002 nucleotides (nt) and a large open reading frame (nt 108 to 9,746) encoding a polyprotein of 3,212 amino acids (aa) (363.68 kDa). Pairwise comparisons revealed that the PKgMV polyprotein shares 50.5-68.6% nt and 43.1-72.2% aa sequence identity with reported members of the genus Potyvirus. Moreover, phylogenetic analysis indicated that PKgMV is closely related to polygonatum kingianum virus 1 (PKgV1; accession no. MK427056). These results suggest that the PKgMV is a novel member of the genus Potyvirus of the family Potyviridae.

First report of Alternaria alternata causing leaf spot on Polygonatum kingianum in China.

Polygonatum kingianum is a Chinese herbal medicine that belongs to the genus Polygonatum of the family Liliaceae. In June 2023, Polygonatum kingianum Coll. et Hemsl. in nurseries in Qujing, Yunnan Province, China, showed irregular brown spots on the leaves, whole leaf necrosis, and plant death in serious cases, with an incidence of 10-20% (Fig. S1). To identify the pathogens of P. kingianum, six diseased samples were collected from nurseries with 0.6 acre. These diseased sample leaves were soaked in 0.1% HgCl2 for 1 min and 75% ethanol for 2 min and then rinsed thrice with sterile water. Treated leaves were cut into small pieces (5×5 mm) and cultured on potato dextrose agar (PDA) for five days at 28°C. Total thirteen fungal strains were isolated from PDA medium. The nuclear ribosomal internal transcribed spacer of ribosomal DNA (ITS rDNA) region of these 13 strains was amplified by polymerase chain reaction (PCR) using universal primers ITSI/ITS4 (White et al. 1990). Sequencing and BLAST of the ITS region on NCBI showed that 11 out of 13 fungal strains belonged to the genus Alternaria, with an identity ≥99%. We selected one of the Alternaria strains, HJ-A1, for further study. The HJ-A1 colony appeared grayish brown white-to-gray with a flocculent texture on the front side and a dark gray underside on the PDA medium (Fig. S1). The conidiophores appeared brown, either single or branched, and produced numerous short conidial chains. The conidia were obclavate to obpyriform or ellipsoid in shape and contained 1-4 transverse septa and 0-2 oblique septa. The conidial diameter was 27.30µm in length and 12.27µm in width. (Fig. S1). To further determine the species of HJA1, the genomic DNA of HJ-A1 was extracted using the Lysis Buffer for PCR (AG, Hunan, China). Four Alternaria genomic DNA regions including the ITS, translation elongation factor 1-α gene (TEF1-α), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and Alternaria major allergen gene (Alt a1) were amplified by PCR using the primers as previously reported (Woudenberg et al. 2013, Hong et al. 2005). Sequence analysis revealed that the ITS (484bp) of HJ-A1 (NCBI No. PP082633), TEF1-α (267bp) of HJ-A1 (NCBI No. PP419893), GAPDH (582bp) of HJ-A1 (NCBI No. PP419892), and Alt a1 (522bp) of HJ-A1 (NCBI No. PP228046) shared the highest identity with A. alternata respectively (99≥%). A maximum likelihood phylogenetic tree was constructed with the combined sequence data sets of ITS, GAPDH, TEF, and Alt a1 using MEGA 7. The results showed that HJ-A1 strain clustered with A. alternate (Fig. S2). The pathogenicity of HJ-A1 was tested according to Koch's postulates by inoculating HJ-A1 conidia suspension (2×105 conidia/mL) into leaves of 1-year-old P. kingianum, with sterile water as a control. Each treatment group included 3 plants with 3 replicates. The tested plants were planted in a phytotron at 28℃ and 90% humidity. Three days after inoculation, symptoms similar to those under natural conditions were observed in the HJ-A1-inoculated plants, whereas no symptoms were observed in the control plants (Fig. S1). The same fungal strains were re-isolated from inoculated leaves and identified by morphologically and sequence of ITS. Previous studies showed that Alternaria alternata funji cause many plant diseases, such as fig fruit rot (Latinovic N et al. 2014)，daylily leaf spot (Huang D et al. 2022), fruit blight on sesame (Cheng H et al. 2021)，leaf spot of Cynanchum atratum Bunge (Sun H et al. 2021) and so on. To our knowledge, this is the first report of A. alternata causing P. kingianum leaf spot in China. The discovery of this pathogen will help to guide the protection and control of P. kingianum disease.

Circ-PRMT5 stimulates the proliferative ability in Wilms' tumor through the miR-7-5p/KLF4 axis.

CircRNAs are extensively discovered in mammals and they are closely linked to tumor cell behaviors. This study aims to detect the expression pattern of circ-PRMT5 in Wilms' tumor and its ability in influencing tumor development. Circ-PRMT5 levels in Wilms' tumor samples were detected. The regulatory effect of circ-PRMT5 on proliferative ability in Wilms' tumor cells was assessed by cell counting kit-8 (CCK-8), colony formation and 5-Ethynyl-2'- deoxyuridine (EdU) assay. The interaction in the circ-PRMT5/miR-7-5p/KLF4 axis was determined by luciferase assay. Rescue experiments were conducted to reveal the role of the circ-PRMT5/miR-7-5p/KLF4 axis in Wilms' tumor development. Circ-PRMT5 was highly expressed in Wilms' tumor samples. High levels of circ-PRMT5 predicted advanced tumor staging in patients with Wilms' tumor. Knockdown of circ-PRMT5 markedly suppressed proliferative ability in Wilms' tumor cells. Luciferase assay confirmed the interaction in the circ-PRMT5/miR-7-5p/KLF4 axis. Rescue experiments finally identified that circ-PRMT5 stimulated the malignant development of Wilms' tumor by activating the miR-7-5p/KLF4 axis. Circ-PRMT5 is upregulated in Wilms' tumor samples, which is closely linked to its tumor staging. It stimulates proliferative ability in Wilms' tumor cells by activating the miR-7-5p/KLF4 axis.

Factors associated with in-hospital recurrence of intestinal intussusception in children.

BACKGROUND: A minority of children experience in-hospital recurrence of intestinal intussusception after treatment. This study investigated the factors associated with in-hospital recurrence of intussusception in pediatric patients in China. METHODS: This retrospective study included patients aged 0-18 years-old with intestinal intussusception treated at Hainan Women and Children's Medical Center between January 2019 and December 2019. Demographic and clinical characteristics were extracted from the medical records. Factors associated with in-hospital recurrence of intussusception were identified by logistic regression analysis. RESULTS: The analysis included 624 children (400 boys) with a median age of 1.8 years (range, 2 months and 6 days to 9 years). Seventy-three children (11.7%) had in-hospital recurrence of intussusception after successful reduction with air enema. Multivariate logistic regression analysis identified age > 1 year-old (odds ratio [OR]: 7.65; 95% confidence interval [95%CI]: 2.70-21.71; P < 0.001), secondary intestinal intussusception (OR: 14.40; 95%CI: 4.31-48.14; P < 0.001) and mesenteric lymph node enlargement (OR: 1.90; 95%CI: 1.13-3.18; P = 0.015) as factors independently associated with in-hospital recurrence of intussusception. CONCLUSIONS: Age > 1 year-old, secondary intussusception and mesenteric lymph node enlargement were independently associated with increased odds of in-hospital recurrence of intussusception after successful reduction with air enema.

Advances and Prospects of Virus-Resistant Breeding in Tomatoes.

Plant viruses are the main pathogens which cause significant quality and yield losses in tomato crops. The important viruses that infect tomatoes worldwide belong to five genera: Begomovirus, Orthotospovirus, Tobamovirus, Potyvirus, and Crinivirus. Tomato resistance genes against viruses, including Ty gene resistance against begomoviruses, Sw gene resistance against orthotospoviruses, Tm gene resistance against tobamoviruses, and Pot 1 gene resistance against potyviruses, have been identified from wild germplasm and introduced into cultivated cultivars via hybrid breeding. However, these resistance genes mainly exhibit qualitative resistance mediated by single genes, which cannot protect against virus mutations, recombination, mixed-infection, or emerging viruses, thus posing a great challenge to tomato antiviral breeding. Based on the epidemic characteristics of tomato viruses, we propose that future studies on tomato virus resistance breeding should focus on rapidly, safely, and efficiently creating broad-spectrum germplasm materials resistant to multiple viruses. Accordingly, we summarized and analyzed the advantages and characteristics of the three tomato antiviral breeding strategies, including marker-assisted selection (MAS)-based hybrid breeding, RNA interference (RNAi)-based transgenic breeding, and CRISPR/Cas-based gene editing. Finally, we highlighted the challenges and provided suggestions for improving tomato antiviral breeding in the future using the three breeding strategies.

Epigenetic therapy attenuates oxidative stress in BMSCs during ageing.

Oxidative stress, a hallmark of ageing, inhibits the osteogenic differentiation of bone marrow-derived mesenchymal stem cells in long bone. The dysfunction of the cellular antioxidant defence system is a critical cause of oxidative stress, but the mechanism of the decline of antioxidant defence in senescent stem cells remains elusive. Here, we found that EZH2, an epigenetic regulator of histone methylation, acted as a suppressor of the antioxidative defence system in BMSCs from the femur. The increased EZH2 led to a decrease in the levels of antioxidant enzymes and exaggerated oxidative damage in aged BMSCs, resulting in the defect of bone formation and regeneration. Mechanistically, EZH2 enhanced the modification of H3K27me3 on the promoter of Foxo1 and suppressed its function to activate the downstream genes in antioxidant defence. Moreover, epigenetic therapy targeting EZH2-mediated H3K27me3 modification largely recovered the antioxidant defence in BMSCs and attenuate oxidative damage, leading to the recovery of the osteogenesis in old BMSCs. Taken together, our findings revealed novel crosstalk between histone epigenetic modification and oxidative stress during stem cell ageing, suggesting a possibility of epigenetic therapy in the recovery of BMSCs senescence and treatment of age-related bone disease.

First report of Stenotrophomonas maltophilia causing root soft rot of Sanqi (Panax notoginseng) in China.

Sanqi (Panax notoginseng (Burk.) F. H. Chen) is a traditional Chinese medicinal plant with a long planting cycle of 2-3 years that makes it vulnerable to root diseases caused by several pathogens, including Fusarium solani, Alternaria panax, Phytophthoracactorum, and Pseudomonas sp. In April 2019, root soft rot samples of Sanqi were collected from a plantation site in Songming, southwest of China. Typical symptoms included root softening and necrosis, yellow leaf, and stem wilting. Ten diseased roots samples were collected and sterilized with 0.1% HgCl2 for 1 min, 75% ethanol for 2min, and then rinsed thrice with sterile water. Sterilized roots were cut into small pieces of 5 × 5 mm and cultured on the nutrient agar (NA) medium for 48 h at 28°C. From the root cultures, a total of thirteen bacterial strains were obtained. Three strains, SM 2-5, SM 2-13, and SM 2-14 were selected for further study. These three strains were gram-negative, short rod-shaped (1～2×0.5～1µm), non-spore-forming and had polar tufted flagella as observed under a transmission electron microscope (TEM). Also, the strains were positive for oxidase, beta-galactosidase, arginine dihydrolase, and lysine decarboxylase while negative for amylase and urease tested by biochemical methods (Wang 2017). To further determine the pathogenic species, genomic DNA of these three strains was extracted using a Genomic DNA Kit (Tsing Ke, Beijing, China), to PCR amplify 16S rDNA using universal primers 27F/1492R (Wang et al. 2017). Also, S. maltophilia 23S rDNA specific primers SM1/SM4 (Whitby et al. 2000) were used for PCR amplification to confirm the species. 16S rDNA sequence analysis showed that SM 2-5 (GenBank Accession No. MW555227), SM 2-13 (GenBank Accession No. MW555228), and SM 2-14 (GenBank Accession No. MW555229) shared the highest identity (>99.9%) with the S. maltophilia strains (GenBank Accession No. MT323142, MH669295, MN826555). Furthermore, 23S rDNA sequence analysis of SM 2-5 (GenBank Accession No. MZ707732), SM 2-13 (GenBank Accession No. MZ645941) and SM 2-14 (GenBank Accession No. MZ707733) revealed their high identity (>99.8%) with the S. maltophilia species. 16S and 23S rDNA phylogenetic analysis (Mega6.06) using the neighbor-joining (NJ) method with 1,000 bootstrap replicates revealed the three strains clustering with the other S. maltophilia strains. Therefore, based on morphology, metabolic profile, and sequence analysis, the three strains were identified as Stenotrophomonas maltophilia. To test pathogenicity, the strains were grown in the nutrient broth (NB) medium for 48h at 28°C until bacterial suspension reached to OD600≈1.0 (2.0×109CFU/mL). Then, healthy roots of one-year-old Sanqi plants, pre-washed with sterilized water and -poked with a sterilized needle, were soaked in bacterial suspension (2.0×109CFU/mL) of the three strains separately for inoculation 10min. Sterilized water treatment was used as a control. Subsequently, bacteria-inoculated plants were planted in sterile soil pots and cultured in a greenhouse at 28°C with shading rate of 70%. Each treatment group included 3 plants with 3 replicates. Ten days post inoculation, symptoms similar to the ones in natural conditions were observed in the bacteria-inoculated plants. Based on the disease index (Li et al. 2020), we found that among the three strains, SM 2-13 displayed the highest virulence, while no symptoms were observed in the control plants. The same bacterial strains were re-isolated from these inoculated roots and identified by the methods described above. Previous studies showed that some Stenotrophomonas species cause plant diseases such as rice white stripe (Singh et al. 2001), strawberry leaf black spot (Wang et al. 2017), Cyclobalanopsis patelliformis leaf spot (Bian et al. 2020), and Jatropha curcas L. seed borne and stem necrosis (Wang et al. 2018). To our knowledge, this is the first report confirming Stenotrophomonas maltophilia causing root soft rot of Panax notoginseng in China.

First report of wild tomato mosaic virus infecting chilli pepper in China.

Chilli pepper is an important economic crop and virus diseases are constraints on its production. In 2018, disease surveys were conducted at a 15-ha chilli pepper plantation in Dehong, southwest of Yunnan Province, China. Throughout the chilli pepper growing season from March to September, pepper plants developed three different virus-like symptoms on leaves, including mosaic, yellow mottle and shrinkage (Fig. S1). Based on observation of virus-like symptomatic phenotypes, the field surveys indicated that the disease incidence ranged from 30% in March to a peak 100% in July, resulting in a significant loss of pepper fruit from 30 to 100% depending on plot of the field. Potyvirus-like filamentous particles, around 11*760 nm, were observed under electron microscopy in the sap of symptomatic leaves (Fig. S1). To further determine the viral species in these samples, total RNA was extracted from three symptomatic samples using a Trans ZolUp Plus RNA Kit (Trans Gene, Beijing, China). Complementary DNA (cDNA) was synthesized using oligo (dT) and M-MLV reverse transcriptase (Promega, Madison, Wisconsin, USA) according to the manufacturer's instructions, and the polymerase chain reaction (PCR) was performed using degenerate primers specific to genus Potyvirus targeting HC-Pro region (HPFor: 5-TGYGAYAAYCARYTIGAYIIIAAYG-3; HPRev: 5-GAICCRWAIGARTCIAIIACRTG-3) (Ha et al. 2008) under the following conditions: an initial denaturation at 94°C for 4min, 30 cycles of denaturation at 94°C for 30 s, annealing at 56°C for 30 s, extension at 72°C for 30s, and a 10min final extension at 72°C. An expected 683-bp DNA fragment was amplified and cloned into the pMD 18-T Vector (Takara, Japan) for sequencing. Sequence analysis using BLAST revealed that the amplicons of phenotype I (Fig. S1a) shared highest nucleotide identity (85.6%) with wild tomato mosaic virus (WTMV) isolate from Vietnam (GenBank no. DQ851495) while the amplicons of phenotype III (Fig. S1c) showed the highest nucleotide identity (93%) with chilli veinal mottle virus (ChiVMV) isolate from Sichuan, China. (GenBank no. MK405594). Amplicons of phenotype II included both sequence of above WTMV and ChiVMV, indicating co-infection of phenotype II (Fig. S1b). Phenotype I sample was used for mechanical inoculation on chilli pepper as described previously (Yang et al.2013). After ten days, virus-like symptoms similar to phenotype I were observed on leaves, and WTMV infection, but not ChiVMV infection, was confirmed by RT-PCR tests on inoculated pepper plants (Fig. S1 e, f). To further ascertain the incidence of these two viruses in the field, primers WT-F: 5'-GTTGTTGAATGTGGTTTAGTT-3' and WT-R: 5'-AGATGTGCTTTGGAAGCGACC-3' were designed based on the WTMV sequence (GenBank no. DQ851495) to amplify a 476 bp product, and primers Ch-F/Ch-R (Ch-F: 5'-AAAGAAGAACAAGCGACAGAA-3', Ch-R: 5'-CATCACGCAAATATTCAAAGC-3') were designed based on ChiVMV sequence (GenBank no. MK405594.1) to amplify a 332 bp product. RT-PCR was conducted on 31 field-collected samples, and amplicons of expected sizes, 476bp and 332bp, corresponding to WTMV and ChiVMV, respectively, were obtained and sequenced to verify their identity. The results (Fig. S2) showed that 71% (22/31) of the samples tested positive for WTMV, 90% (28/31) tested positive for ChiVMV, and 65% (20/31) were co-infected with the two viruses. The WTMV was first reported infecting wild tomatoes in Vietnam in 2008 (Ha et al. 2008), and later reported in China in Nicotiana tabacum (Sun et al. 2015), Solanum nigrum (Zhang et al. 2019), and wild eggplant (Zhang et al. 2014). To our knowledge, this is the first report of WTMV infection on chilli pepper under natural conditions. Our study revealed that the chilli pepper disease in Dehong was caused by single or co-infection of WTMV and ChiVMV. It is necessary to find effective methods to control these two viruses.

Redundant let-7a suppresses the immunomodulatory properties of BMSCs by inhibiting the Fas/FasL system in osteoporosis.

Bone marrow-derived mesenchymal stem cell (BMSC) cytotherapy has emerged as a promising treatment strategy for refractory immune diseases; however, the influence of the pathologic conditions of donors on the immunomodulatory properties of BMSCs is still poorly understand. Here, we found that BMSCs that were derived from donors with osteoporosis were ineffective as cytotherapy for patients with experimental colitis and graft- vs.-host disease (GVHD). In vivo and in vitro assays revealed that the capacity of osteoporotic BMSCs to induce T-cell apoptosis declined as a result of decreased Fas and FasL protein. Additional analysis revealed that let-7a, a microRNA induced by TNF-α in osteoporosis, inhibited the expression of the Fas/FasL system via post-transcriptional regulation. By knocking down let-7a expression, we successfully recovered the immunosuppressive capacity of osteoporotic BMSCs and improved their therapy for experimental colitis and GVHD. Taken together, our study demonstrates that the immunomodulatory properties of BMSCs are suppressed in osteoporosis and illustrates the molecular mechanism that underlies this suppression. These findings might have important implications for the development of targeted strategies to improve BMSC cytotherapy.-Liao, L., Yu, Y., Shao, B., Su, X., Wang, H., Kuang, H., Jing, H., Shuai, Y., Yang, D., Jin, Y. Redundant let-7a suppresses the immunomodulatory properties of BMSCs by inhibiting the Fas/FasL system in osteoporosis.

Transcriptome profiling provides insights into dormancy release during cold storage of Lilium pumilum.

BACKGROUND: Bulbs of the ornamental flower Lilium pumilum enter a period of dormancy after flowering in spring, and require exposure to cold for a period of time in order to release dormancy. Previous studies focused mainly on anatomical, physiological and biochemical changes during dormancy release. There are no dormancy studies of the northern cold-hardy wild species of Lilium at the molecular level. This study observed bulb cell and starch granule ultrastructures during cold storage; and analysed the transcriptome using sequencing. The combination of morphological and transcriptomic methods provides valuable insights into dormancy release during cold storage of Lilium pumilum. RESULTS: Ultrastructural changes reflected dormancy release during cold storage of the bulbs. We compared gene expression levels among samples at 0 (S1 stage), 30 (S2 stage), 60 (S3 stage) and 90 (S4 stage) d of cold storage, with 0 d as the control. The data showed that some regulatory pathways such as carbohydrate metabolism and plant hormone signal transduction were activated to break dormancy. Some differentially expressed genes (DEGs) related to antioxidant activity, epigenetic modification and transcription factors were induced to respond to low temperature conditions. These genes constituted a complex regulatory mechanism of dormancy release. CONCLUSIONS: Cytological data related to dormancy regulation was obtained through histomorphological observation; transcriptome sequencing provided comprehensive sequences and digital gene expression tag profiling (DGE) data, and bulb cell ultrastructural changes were closely related to DEGs. The novel Lilium pumilum genetic information from this study provides a reference for the regulation of dormancy by genetic engineering using molecular biology tools.

Declining histone acetyltransferase GCN5 represses BMSC-mediated angiogenesis during osteoporosis.

Angiogenesis is disrupted in age-related and postmenopausal osteoporosis. However, the mechanisms of the disorder remain elusive. We confirmed in this study that, in accordance with the decrease of H-type vessels, the proangiogenic potential of bone marrow-derived mesenchymal stem cells (BMSCs) declined during osteoporosis. Screening of the histone acetyltransferase family revealed that GCN5 decreased in BMSCs derived from osteoporotic femur. Further analysis identified that GCN5 plays important roles in regulating the proangiogenic potential of BMSCs. GCN5 promoted BMSC-mediated angiogenesis by enhancing H3K9ac levels on the promoter of Vegf The decrease of GCN5 in osteoporotic BMSCs led to the decline of proangiogenic capacity. Accordingly, overexpression of GCN5 enhanced the proangiogenic potency of osteoporotic BMSCs. Furthermore, recovering GCN5 expression in vivo by lentiviral expression vector significantly attenuated the loss of angiogenesis in ovariectomized mouse femurs. Our study results revealed an epigenetic mechanism controlling BMSC-mediated angiogenesis and provided a novel therapeutic target for osteoporosis treatment.-Jing, H., Liao, L., Su, X., Shuai, Y. Zhang, X., Deng, Z., Jin, Y. Declining histone acetyltransferase GCN5 represses BMSC-mediated angiogenesis during osteoporosis.

Knockdown of MicroRNA Let-7a Improves the Functionality of Bone Marrow-Derived Mesenchymal Stem Cells in Immunotherapy.

Bone marrow-derived mesenchymal stem cells (MSCs) have been recently used in clinical treatment of inflammatory diseases. Practical strategies improving the immunosuppressive property of MSCs are urgently needed for MSC immunotherapy. In this study, we aimed to develop a microRNA-based strategy to improve MSC immunotherapy. Bioinformatic analysis revealed that let-7a targeted the 3' UTR of mRNA of Fas and FasL, both of which are essential for MSCs to induce T cell apoptosis. Knockdown of let-7a by specific inhibitor doubled Fas and Fas ligand (FasL) protein levels in MSCs. Because Fas attracts T cell migration and FasL induces T cell apoptosis, knockdown of let-7a significantly promoted MSC-induced T cell migration and apoptosis in vitro and in vivo. Importantly, MSCs knocked down of let-7a were more efficient to reduce the mortality, prevent the weight loss, suppress the inflammation reaction, and alleviate the tissue lesion of experimental colitis and graft-versus-host disease (GVHD) mouse models. In conclusion, knockdown of let-7a significantly improved the therapeutic effect of MSC cytotherapy on inflammatory bowel diseases and GVHD. With high safety and convenience, knockdown of let-7a is a potential strategy to improve MSC therapy for inflammatory diseases in clinic.

TNF-α Inhibits FoxO1 by Upregulating miR-705 to Aggravate Oxidative Damage in Bone Marrow-Derived Mesenchymal Stem Cells during Osteoporosis.

Decline of antioxidant defense after estrogen deficiency leads to oxidative damage in bone marrow-derived mesenchymal stem cells (BMMSCs), resulting a defect of bone formation in osteoporosis. Forkhead box O1 (FoxO1) protein is crucial for defending physiological oxidative damage in bone. But whether FoxO1 is involved in the oxidative damage during osteoporosis is largely unknown. In this study, we found that FoxO1 protein accumulation was decreased in BMMSCs of ovariectomized mice. The decrease of FoxO1 resulted in the suppression of manganese superoxide dismutase (Sod2) and catalase (Cat) expression and accumulation of reactive oxygen species (ROS), inhibiting the osteogenic differentiation of BMMSCs. The decline of FoxO1 protein was caused by tumor necrosis factor-alpha (TNF-α) accumulated after estrogen deficiency. Mechanistically, TNF-α activated NF-κB pathway to promote microRNA-705 expression, which function as a repressor of FoxO1 through post-transcriptional regulation. Inhibition of NF-κB pathway or knockdown of miR-705 largely prevented the decline of FoxO1-mediated antioxidant defense caused by TNF-α and ameliorated the oxidative damage in osteoporotic BMMSCs. Moreover, the accumulated ROS further activated NF-κB pathway with TNF-α, which formed a feed-forward loop to persistently inhibiting FoxO1 protein accumulation in BMMSCs. In conclusion, our study revealed that the decline of FoxO1 is an important etiology factor of osteoporosis and unclosed a novel mechanism of FoxO1 regulation by TNF-α. These findings suggested a close correlation between inflammation and oxidative stress in stem cell dysfunction during degenerative bone diseases.

Complete genome sequence of a new isolate of potato virus M in Yunnan, China.

The complete genome sequence of a new potato virus M (PVM) isolate (PVM-YN), collected from potato (Solanum tuberosum) in Yunnan, China, was determined. It was 8,530 nucleotides (nt) in length, excluding the poly(A) tail at the 3' end, and shared 71.4-72.0% nucleotide sequence identity with available PVM isolates in the NCBI database. The coat proteins (CP) of PVM-YN shared 79.0-97.4% amino acid sequence identity with that of other isolates. It is the first report of the complete genomic sequence of a new PVM isolate infecting S. tuberosum in China.

Characterization of a new isolate of pepper chlorotic spot virus from Yunnan province, China.

A new isolate, 14YV733, of pepper chlorotic spot virus (PCSV) from chili peppers in Yunnan province of China was identified. The typical tospoviral particles of 80-120 nm in diameter were observed by electron microscopy. The virus caused systemic symptoms in several solanaceous plants and the Brassica rapa L. Chinensis group with mechanical inoculation. The sap from infected leaves reacted positively to a rabbit antibody to the N protein of watermelon silver mottle virus (WSMoV) in immunoblotting. The S, M, and L RNAs of PCSV-14YV733 are 3310 nts, 4711 nts, and 8913 nts long, respectively. This is the first report of complete sequences of PCSV in mainland China. Phylogenetic analysis of all tospoviral proteins indicated that PCSV-14YV733 is closely related to members of the WSMoV serogroup.

Suppression of EZH2 Prevents the Shift of Osteoporotic MSC Fate to Adipocyte and Enhances Bone Formation During Osteoporosis.

During osteoporosis, the shift of mesenchymal stem cell (MSC) lineage commitment to adipocyte leads to the imbalance between bone mass and fat, which increases the risk of fracture. The Enhancer of Zeste homology 2 (EZH2), which methylates histone H3 on lysine 27 (H3K27me3), controls MSC cell lineage commitment. However, whether EZH2 is related to osteoporosis remains elusive. In our study, we found EZH2 expression was significantly increased in osteoporotic MSCs. EZH2 directly increased H3K27me3 levels on promoters of Wnt1, Wnt6, and Wnt10a to silence Wnt gene transcription. The inhibition of Wnt/ß-catenin signaling shifted MSC cell lineage commitment to adipocyte. Knockdown of EZH2 by lentivirus-expressing shRNA rescued the abnormal fate of osteoporotic MSC. By employing the H3K27me3 inhibitor DZNep, we effectively derepressed Wnt signaling and improved osteogenic differentiation of osteoporotic MSCs in vitro. Furthermore, in vivo administration of DZNep successfully increased bone formation and repressed excessive bone marrow fat formation in osteoporotic mice. Noteworthy, DZNep treatment persistently enhanced osteogenic differentiation of endogenous MSCs. In conclusion, our study demonstrated that redundant EZH2 shifted MSC cell lineage commitment to adipocyte, which contributed to the development of osteoporosis. We also provided EZH2 as a novel therapeutic target for improving bone formation during osteoporosis.

Anti-TMV activity and functional mechanisms of two sesquiterpenoids isolated from Tithonia diversifolia.

Unlike chemical pesticides, antiviral plants are biodegradable, replenishable and safe. In this study, 14 sesquiterpene compounds from Tithonia diversifolia were tested for their activities against Tobacco mosaic virus (TMV) using the half-leaf method. Tagitinin C (Ses-2) and 1ß-methoxydiversifolin-3-0-methyl ether (Ses-5) were found to have in vivo curative activities of 62.86% and 60.27% respectively, at concentrations of 100µg/mL, respectively. In contrast, the in vivo curative inhibition rate of control agent ningnanmycin was 52.48%. Indirect enzyme-linked immunosorbent assay (ID-ELISA) also verified Ses-2 and Ses-5 had higher inhibition activities than the control agent ningnanmycin. Additionally, qRT-PCR showed that both Ses-2 and Ses-5 can partly inhibit the expression of CP and RdRp, two genes that play key roles in TMV infection. When TMV started to systemically spread, Ses-2 inhibited CP expression while Ses-5 inhibited RdRp expression. These results suggest that the two bio-agents have anti-TMV activities and may be used as bio-pesticides to control the plant virus.

Estrogen preserves Fas ligand levels by inhibiting microRNA-181a in bone marrow-derived mesenchymal stem cells to maintain bone remodeling balance.

Estrogen protects bone loss by promoting Fas ligand (FasL) transcription in osteoclasts and osteoblasts to induce apoptosis of osteoclasts. Bone marrow-derived mesenchymal stem cells (BMMSCs) express FasL protein, which is necessary for BMMSCs to induce T-cell apoptosis in cell therapy. However, the physiologic function of FasL in BMMSCs is unknown. In this study, using an in vitro coculture system and an in vivo BMMSC transplantation assay, we found that BMMSCs potently induced apoptosis of osteoclasts through the FasL/Fas pathway. Estrogen was necessary for this process as a promoter of FasL protein accumulation in BMMSCs. Furthermore, estrogen elevated FasL protein accumulation, not by increasing FasL gene transcription, but through microRNA-mediated posttranscriptional regulation. In brief, estrogen down-regulated expression of miR-181a, a negative modulator of FasL targeting the 3'-UTR of FasL mRNA. Estrogen deficiency resulted in excessive miR-181a, which decreased FasL protein levels to suppress BMMSC-induced osteoclast apoptosis. Furthermore, knockdown of miR-181a recovered the BMMSC defect to induce osteoclast apoptosis during estrogen deficiency. Taken together, our results showed that estrogen preserves FasL protein accumulation by inhibiting miR-181a expression in BMMSCs to maintain bone remodeling balance, suggesting a novel mechanism by which estrogen preserves bone mass.