The Ralstonia solanacearum Type III Effector RipAW Targets the Immune Receptor Complex to Suppress PAMP-Triggered Immunity.

Bacterial wilt, caused by Ralstonia solanacearum, one of the most destructive phytopathogens, leads to significant annual crop yield losses. Type III effectors (T3Es) mainly contribute to the virulence of R. solanacearum, usually by targeting immune-related proteins. Here, we clarified the effect of a novel E3 ubiquitin ligase (NEL) T3E, RipAW, from R. solanacearum on pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) and further explored its action mechanism. In the susceptible host Arabidopsis thaliana, we monitored the expression of PTI marker genes, flg22-induced ROS burst, and callose deposition in RipAW- and RipAWC177A-transgenic plants. Our results demonstrated that RipAW suppressed host PTI in an NEL-dependent manner. By Split-Luciferase Complementation, Bimolecular Fluorescent Complimentary, and Co-Immunoprecipitation assays, we further showed that RipAW associated with three crucial components of the immune receptor complex, namely FLS2, XLG2, and BIK1. Furthermore, RipAW elevated the ubiquitination levels of FLS2, XLG2, and BIK1, accelerating their degradation via the 26S proteasome pathway. Additionally, co-expression of FLS2, XLG2, or BIK1 with RipAW partially but significantly restored the RipAW-suppressed ROS burst, confirming the involvement of the immune receptor complex in RipAW-regulated PTI. Overall, our results indicate that RipAW impairs host PTI by disrupting the immune receptor complex. Our findings provide new insights into the virulence mechanism of R. solanacearum.

COP1 Mediates Dark-Induced Stomatal Closure by Suppressing FT, TSF and SOC1 Expression to Promote NO Accumulation in Arabidopsis Guard Cells.

RING-finger-type ubiquitin E3 ligase Constitutively Photomorphogenic 1 (COP1) and floral integrators such as FLOWERING LOCUS T (FT), TWIN SISTER OF FT (TSF) and SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1 (SOC1) have been identified as regulators of stomatal movement. However, little is known about their roles and relationship in dark-induced stomatal closure. Here, we demonstrated that COP1 is required for dark-induced stomatal closure using cop1 mutant. The cop1 mutant closed stomata in response to exogenous nitric oxide (NO) but not hydrogen peroxide (H2O2), and H2O2 but not NO accumulated in cop1 in darkness, further indicating that COP1 acts downstream of H2O2 and upstream of NO in dark-induced stomatal closure. Expression of FT, TSF and SOC1 in wild-type (WT) plants decreased significantly with dark duration time, but this process was blocked in cop1. Furthermore, ft, tsf, and soc1 mutants accumulated NO and closed stomata faster than WT plants in response to darkness. Altogether, our results indicate that COP1 transduces H2O2 signaling, promotes NO accumulation in guard cells by suppressing FT, TSF and SOC1 expression, and consequently leads to stomatal closure in darkness. These findings add new insights into the mechanisms of dark-induced stomatal closure.

Ethylene Acts as a Local and Systemic Signal to Mediate UV-B-Induced Nitrate Reallocation to Arabidopsis Leaves and Roots via Regulating the ERFs-NRT1.8 Signaling Module.

Nitrate is the preferred nitrogen source for plants and plays an important role in plant growth and development. Under various soil stresses, plants reallocate nitrate to roots to promote stress tolerance through the ethylene-ethylene response factors (ERFs)-nitrate transporter (NRT) signaling module. As a light signal, ultraviolet B (UV-B) also stimulates the production of ethylene. However, whether UV-B regulates nitrate reallocation in plants via ethylene remains unknown. Here, we found that UV-B-induced expression of ERF1B, ORA59, ERF104, and NRT1.8 in both Arabidopsis shoots and roots as well as nitrate reallocation from hypocotyls to leaves and roots were impaired in ethylene signaling mutants for Ethylene Insensitive2 (EIN2) and EIN3. UV-B-induced NRT1.8 expression and nitrate reallocation to leaves and roots were also inhibited in the triple mutants for ERF1B, ORA59, and ERF104. Deletion of NRT1.8 impaired UV-B-induced nitrate reallocation to both leaves and roots. Furthermore, UV-B promoted ethylene release in both shoots and roots by enhancing the gene expression and enzymatic activities of ethylene biosynthetic enzymes only in shoots. These results show that ethylene acts as a local and systemic signal to mediate UV-B-induced nitrate reallocation from Arabidopsis hypocotyls to both leaves and roots via regulating the gene expression of the ERFs-NRT1.8 signaling module.

[High-Throughput Sequencing Technology for Detection of Gene Mutations in Myeloid Malignancies and Its Clinical Prognostic Significance].

OBJECTIVE: To detect the gene mutations in patients with myeloid malignancies by high-throughput sequencing and explore the correlation between gene mutations and prognosis. METHODS: A retrospective analysis was performed on 56 patients with myeloid malignancies who were hospitalized in the department of hematology, Peking University International Hospital from January 2020 to May 2021. The genetic mutations of the patients were detected by next-generation sequencing technology, and the correlation between the genetic mutations and prognosis of myeloid malignancies was analyzed. RESULTS: In 56 patients, the number of mutated genes detected in a single patient is 0-9, with a median of 3. Sequencing results showed that the most common mutated genes were RUNX1(21.4%), TET2(17.9%), DNMT3A(17.9%), TP53(14.3%) and ASXL1(14.3%), among which the most common mutations occurred in the signaling pathway-related genes (23.3%) and the transcription factor genes (18.3%). 84% of the patients carried multiple mutated genes (≥2), and correlation analysis showed there were obvious co-occurring mutations between WT1 and FLT3, NPM1 and FLT3-ITD, and MYC and FLT3. TP53 mutation was more common in MDS patients.The overall survival time of patients with NRAS mutation was significantly shortened (P =0.049). The prognosis of patients with TP53 mutation was poor compared with those without TP53 mutation, but the difference wasn't statistically significant (P =0.08). CONCLUSION: The application of next-generation sequencing technology is of great significance in myeloid malignancies, which is helpful to better understand the pathogenesis of the disease, to judge the prognosis and to find possible therapeutic targets.

[Clinical Study of Blinatumomab in the Treatment of Adult Relapsed/Refractory Ph-Negative Acute B-Lymphoblastic Leukemia].

OBJECTIVE: To investigate the efficacy and safety of CD19/CD3 bisecific monoclonalantibody (Blinatumomab) in the treatment of adult patients with relapsed / refractory Ph-negative acute B-lymphoblastic leukemia (R/R-B-ALL). METHODS: Ten adult R/R B-ALL patients were all treated with Blinatumomab. Each treatment cycle was administered for 28 days and stopped for 14 days. The dose was 9 µg/day for the first 7 days of cycle 1, and 28 µg/day for days 8-28 if there were no adverse reactions. From the second cycle onwards, the daily dose was 28 µg. The remission, survival time (EFS and OS) and adverse reactions were observed after treatment. RESULTS: Nine patients with curative effect could be evaluated. Four patients achieved CR after one course, and one patient achieved CR after two courses, the overall remission rate was 55.6%(5/9). The median EFS was 4 months (1-12 months), and the median OS was 6 months (2-44 months). Nine of the 10 patients had fever of different degrees. Serum levels of cytokines such as IL-6, IL-10, IL-17 and IFN-γ increased. Two patients resumed medication after 1 week of treatment interruption due to neurotoxicity and CRS, respectively. One patient was discontinued due to grade 3 CRS and died of tropical candidiaemia. CONCLUSION: Blinatumomab has a good response rate in the treatment of relapsed/refractory B-ALL patients, but the duration of remission is shorter. Drug-related adverse reactions are mainly CRS and neurotoxicity. Inflammatory factors IL-6, IL-10, IL-17 and IFN-γ can be used as indicators to monitor CRS. The bisspecificity MAbs provide an opportunity for subsequent allogeneic hematopoietic stem cell transplantation in R/R-B-ALL patients.

[Pedigree Analysis of ACTN1-Related Thrombocytopenia Attributed to A Novel Mutation].

AbstractObjective: To investigate the clinical phenotype and genotype of an ACTN1-associated thrombocytopenic family and explore its molecular pathogenesis. METHODS: All the family members' peripheral blood was collected for routine blood tests, blood smear, coagulation function, and platelet aggregation test. Flow cytometry was used to detect the expression of platelet CD41 and CD61. The proband and her father were tested bone marrow cytomorphology. Whole-exome sequencing techniques were performed to detect and uncover mutant loci of suspected pathogenic genes. Bioinformatics was used to assess the conserved nature of the mutated loci and to analyze the effect of the mutated genes leading to the function of the corresponding amino acid sequences. RESULTS: The platelet count of the proband was 88×109/L, and the blood smear showed dumbbell-shaped platelets, snake-shaped platelets and platelets of various sizes. Her bone marrow cytomorphology revealed normal megakaryocyte morphology with a count of 270. The platelet count of the proband's father was 74×109/L, with large platelets and platelets of various sizes observed in the blood smear, and the morphology of megakaryocytes was normal in bone marrow with a megakaryocyte count of 239. Her grandfather had a platelet count of 83×109/L, with snake-shaped platelets and platelets of various sizes on blood smears. Other family members were normal in all tests. The missense mutation c.2396G > A in exon 20 of the ACTN1 gene in the proband resulted in the mutation of 799 amino acids of the encoded protein, i.e., Arg, to His. The sequencing results of her father and grandfather at this locus were found to be consistent with her. Furthermore, bioinformatics analysis indicated that the locus was highly conserved across species and that variation in this locus might lead to functional impairment of the protein. The protein model analysis demonstrated that α-actin-1 at position 799 Arg and Glu at position 811 could form a critical salt bridge which stabilizes the conformation of the Ca2+ binding loop within the calmodulin-like motif. the mutation of R799H lost this critical salt bridge and destabilized this structural domain. CONCLUSION: In the present study, the newly uncovered missense mutation c.2396G＞A in exon 20 of the ACTN1 gene is potentially the molecular mechanism for the thrombocytopenia.

JAK2V617F/STAT5 signaling pathway promotes cell proliferation through activation of Pituitary Tumor Transforming Gene 1 expression.

Gain-of-function mutations of JAK2 play crucial roles in the development of myeloproliferative neoplasms; however, the underlying downstream events of this activated signaling pathway are not fully understood. Our experiment was designed and performed to address one aspect of this issue. Here we report that AG490, a potent JAK2V617F kinase inhibitor, effectively inhibits the proliferation of HEL cells. Interestingly, AG490 also decreases the expression of PTTG1, a possible target gene of the aberrant signaling pathway, in a dose- and time-dependent manner. Furthermore, the promoter activity analyses reveal that the inhibition of the PTTG1 expression is affected at the transcriptional level. Thus, our results suggest that the JAK2V617F/STAT5 signaling pathway promotes cell proliferation through the transcriptional activation of PTTG1.

Reduction of PGRN increased fibrosis during skin wound healing in mice.

Progranulin (PGRN) is a multi-functional growth factor known to be involved in regulating of development, cell cycle progression, cell motility, tumorigenesis and angiogenesis. Research has revealed that PGRN is a crucial mediator of skin wound healing. Nonetheless, the role of PGRN in the fibrosis process of cutaneous wound healing has not been identified. In the present study, mice with excisional wounds were treated with si-m-PGRN or physiological saline. We observed the expression of PGRN in intact and post-injury skin by immunohistochemistry. Tissue sections of skin around the wound were performed by hematoxylin & eosin and masson's trichrome staining. After PGRN knockdown by siRNA, the expression of PGRN, collagen I (Col I), small mothers against decapentaplegic homolog 3 (Smad3), phosphorylated Smad3 (P-Smad3), transforming growth factor (TGF)-ß1 and TGF-ß receptor I (TßRI) were detected by real-time reverse transcription polymerase chain reaction (RT-qPCR) or Western blot. PGRN mRNA and protein expressions were increased after insult and remained above that of intact skin through day 20. Down-regulation of PGRN augmented fibrosis area, skin thickness and the expression of Col I. In addition, reduction of PGRN considerably increased the expression of TGF-ß1, TßRI, Smad3 and P-Smad3. These results indicate that PGRN knockdown enhances the fibrosis degree, probably via the TGF-ß/Smad signaling pathway.

[Inducing-apoptosis effect of brucine on human monocytic leukemia cell line THP-1 and its mechanism].

This study was aimed to investigate the inducing-apoptosis effect of brucine on human monocytic leukemia cell line THP-1 cells and its possible mechanism. The inhibition effect of brucine on growth of THP-1 cells was measured by CCK-8 method. Morphological changes of THP-1 cells treated with brucine was detected by acridine orange/ethidium bromide (AO/EB)double staining. Annexin-V/PI double labeling method was used to assay the apoptosis rate of THP-1 cells. The effect of brucine on THP-1 cell cycle distribution was detected by PI single staining. RT-PCR was used to detect the expression of BCL-2 and BAX. The results showed that the brucine could inhibit the THP-1 cell growth in concentration and time-dependent manners at the range of 50 to 400 µg/ml. The cells stained with AO/EB revealed that the brucine induced the nuclear chromatin condensation. After the THP-1 cells were treated with brucine of 400µg/ml for 48 hours, most nucleic were stained as orange-red, and condensed, displaying the late apoptotic cell morphology. Annexin-V/PI detection showed that brucine could induce apoptosis of THP-1 cells in a concentration-dependent manner. Compared with the control group, more cells in brucine-treated group were arrested at G0/G1 phase in a concentration-dependent manner. RT-PCR detection revealed that the expression of BCL-2 was down-regulated strikingly and BAX was up-regulated. It is concluded that brucine can efficiently inhibit cell growth and block THP-1 cells in G0/G1 phase. The mechanism of THP-1 cell apoptosis induced by brucine may be related to the inhibition of BCL-2 and activation of BAX.

Overexpressed ostepontin-c as a potential biomarker for esophageal squamous cell carcinoma.

BACKGROUND: The metastasis gene osteopontin (OPN) is subject to alternative splicing, which yields three messages, osteopontin-a, osteopontin-b and osteopontin-c. Osteopontin-c is selectively expressed in invasive, but not in noninvasive tumors. In the present study, we examined the expression of OPN-c in esophageal squamous cell carcinomas (ESCCs) and assessed its value as a diagnostic biomarker. METHODS: OPN-c expression was assessed by immunohistochemistry in 63 ESCC samples and correlated with clinicopathologic factors. Expression was also examined in peripheral blood mononuclear cells (PBMCs) from 120 ESCC patients and 30 healthy subjects. The role of OPN-c mRNA as a tumor marker was investigated by receiver operating characteristic curve (ROC) analysis. RESULTS: Immunohistochemistry showed that OPN-c was expressed in 30 of 63 cancer lesions (48%)and significantly associated with pathological T stage (P=0.038) and overall stage (P=0.023). Real time PCR showed that OPN-c mRNA was expressed at higher levels in the PBMCs of ESCC patients than in those of healthy subjects (P<0.0001) with a sensitivity as an ESCC biomarker of 86.7%. CONCLUSION: Our findings suggest that expression of OPN-c is significantly elevated in ESCCs and this upregulation could be a potential diagnostic marker.

[Apoptosis-inducing effects of brucine on human chronic myeloid leukemia cell line K562].

To investigate the apoptosis-induction effect of brucine on human chronic myeloid leukemia cell line K562 cells, K562 cells were exposed to various dosages of brucine. MTT method was used to assayed the growth inhibition effect of brucine on K562 cells. The apoptosis of K562 cells was detected by acridine orange/ethidium bromide (AO/EB) double staining, Annexin-V/PI double labeling method and DNA agarose gel electrophoresis. The results showed that brucine could remarkably inhibit the K562 cell growth in a concentration-dependent and time-dependent manners at the range of 50 to 400 µg/ml, and its most significant inhibition was observed at 400 µg/ml for 72 hours and the inhibition rate was 94.0%. Staining of cells with AO-EB revealed that brucine induced nuclear chromatin condensation. After the K562 cells were treated with the brucine of 400 µg/ml for 72 hours, the most of the nucleus were orange stained and condensation-like or bead-like showing apoptotic morphology. The K562 cells treated with brucine of different concentrations (50, 100, 200, 400, 800 µg/ml) for 72 hours, Annexin-V/PI detection showed brucine could induce apoptosis of K562 cells, and apoptosis rate increased gradually with increasing concentration of drugs. The K562 cells treated with brucine of 400 µg/ml for 72 hours displayed typical ladder strap in DNA gel electrophoresis. It is concluded that brucine can efficiently inhibit cell growth and induce apoptosis of K562 cells with dose-dependent manner in concentrations of 50 - 400 µg/ml.