Drug pair of Cornus officinalis and Radix achyranthis bidentatae improves renal injury of hypertension by regulating metabolic reprogramming mediated by eNOS.

Objective: To explore the effects and possible mechanisms of the drug pair Cornus officinalis and Radix achyranthis bidentatae (SYR-NX) on improving hypertensive kidney damage. Method: SYR-NX, a formulation of Cornus officinalis and Radix Achyranthis Bidentatae with a dose ratio 1:2.5, was used in this experiment. We investigated the effects of SYR-NX on spontaneously hypertensive rats (SHR) fed with a high-salt diet and Human Kidney-2 (HK2) cells exposed to hypoxia. After 8 weeks of treatment with SYR-NX, blood pressure was tested, and ß 2-Microglobulin(ß2-MG), blood creatinine (S-cr), endothelial nitric oxide synthase (eNOS), nicotinamide adenine dinucleotide phosphate (NADPH), M2 pyruvate kinase (PKM2), adenosine triphosphate (ATP), pyruvate, lactate, connective tissue growth factor (CTGF) and tumor necrosis factor-α (TNF-α)were measured. HK2 cells pre-treated with SYR-NX were cultured in a three-gas hypoxic incubator chamber (5 % CO2, 1 % O2, 94 % N2) for 12 h, and then eNOS, PKM2, NADPH, ATP, pyruvate, lactate, CTGF and TNF-α were assessed. Results: SYR-NX significantly reduced SBP, DBP, ß2-MG, S-cr, PKM2, pyruvate, lactate, CTGF and TNF-α, and increased eNOS, NADPH, and ATP. Conclusion: SYR-NX can regulate metabolic reprogramming through eNOS and improves hypertensive kidney injury.

Comparison between solid pseudopapillary neoplasms of the pancreas and pancreatic ductal adenocarcinoma with cystic changes using computed tomography.

BACKGROUND: Solid pseudopapillary neoplasms of the pancreas (SPN) share similar imaging findings with pancreatic ductal adenocarcinoma with cystic changes (PDAC with cystic changes), which may result in unnecessary surgery. AIM: To investigate the value of computed tomography (CT) in differentiation of SPN from PDAC with cystic changes. METHODS: This study retrospectively analyzed the clinical and imaging findings of 32 patients diagnosed with SPN and 14 patients diagnosed with PDAC exhibiting cystic changes, confirmed through pathological diagnosis. Quantitative and qualitative analysis was performed, including assessment of age, sex, tumor size, shape, margin, density, enhancement pattern, CT values of tumors, CT contrast enhancement ratios, "floating cloud sign," calcification, main pancreatic duct dilatation, pancreatic atrophy, and peripancreatic invasion or distal metastasis. Multivariate logistic regression analysis was used to identify relevant features to differentiate between SPN and PDAC with cystic changes, and receiver operating characteristic curves were obtained to evaluate the diagnostic performance of each variable and their combination. RESULTS: When compared to PDAC with cystic changes, SPN had a lower age (32 years vs 64 years, P < 0.05) and a slightly larger size (5.41 cm vs 3.90 cm, P < 0.05). SPN had a higher frequency of "floating cloud sign" and peripancreatic invasion or distal metastasis than PDAC with cystic changes (both P < 0.05). No significant difference was found with respect to sex, tumor location, shape, margin, density, main pancreatic duct dilatation, calcification, pancreatic atrophy, enhancement pattern, CT values of tumors, or CT contrast enhancement ratios between the two groups (all P > 0.05). The area under the receiver operating characteristic curve of the combination was 0.833 (95% confidence interval: 0.708-0.957) with 78.6% sensitivity, 81.3% specificity, and 80.4% accuracy in differentiation of SPN from PDAC with cystic changes. CONCLUSION: A larger tumor size, "floating cloud sign," and peripancreatic invasion or distal metastasis are useful CT imaging features that are more common in SPN and may help discriminate SPN from PDAC with cystic changes.

Xue Ping Tablets treat abnormal uterine bleeding via VEGF-ERK1/2 pathway.

Objective: To investigate the protective effects against abnormal uterine bleeding (AUB) and possible mechanisms of Xue Ping tablets (XPT) using a rat model. Methods: A total of 58 unmated female and 25 male SPF SD rats aged 8-9 weeks were selected. Eight unmated female rats were selected as the blank control group according to the complete random method. The other 50 rats were mated in a female/male ratio of 2:1. In the morning after mating, vaginal smears were collected. Presence of vaginal plug or sperm was regarded as the first day of pregnancy. All pregnant rats were given 8.3 mg/kg of mifepristone by gavage at 8:00 a.m. and 100 µg/kg misoprostol by gavage at 6:00 p.m. on the seventh day of pregnancy to induce incomplete abortion, thereby establishing a rat model of AUB. Forty rats were randomly divided into model, low- (220 mg/kg), medium- (441 mg/kg), high-dose (882 mg/kg) XPT, and positive control groups. The positive group was given 130 mg/kg Gong Xue Ning (GXN). The model group and the blank group were given an equal amount of distilled water. Results: Compared with the model group, the volume of bleeding in the positive and middle- and high-dose XPT groups decreased (P < 0.05). Moreover, compared with the model group, the progesterone levels in the positive and XPT groups were significantly increased. Immunohistochemistry showed that XPT significantly decreased the expression levels of VEGF, p-ERK, NF-κB, SAA, MMP-2, MMP-9, TIMP-1, TIMP-2 and TIMP-3. WB results showed that XPT significantly decreased the expression levels of p-ERK, MMP-9, NF-κB, MMP-2 and VEGF. QRT-PCR results showed that XPT significantly decreased the expression levels of VEGF, NF-κB, SAA, MMP-2, TIMP-1, TIMP-2 and TIMP-3 (P < 0.05). Conclusions: XPT could reduce AUB by inhibiting the inflammatory factors involved in the VEGF-ERK1/2 pathway.

Computed tomography-based radiomics diagnostic approach for differential diagnosis between early- and late-stage pancreatic ductal adenocarcinoma.

BACKGROUND: One of the primary reasons for the dismal survival rates in pancreatic ductal adenocarcinoma (PDAC) is that most patients are usually diagnosed at late stages. There is an urgent unmet clinical need to identify and develop diagnostic methods that could precisely detect PDAC at its earliest stages. AIM: To evaluate the potential value of radiomics analysis in the differentiation of early-stage PDAC from late-stage PDAC. METHODS: A total of 71 patients with pathologically proved PDAC based on surgical resection who underwent contrast-enhanced computed tomography (CT) within 30 d prior to surgery were included in the study. Tumor staging was performed in accordance with the 8th edition of the American Joint Committee on Cancer staging system. Radiomics features were extracted from the region of interest (ROI) for each patient using Analysis Kit software. The most important and predictive radiomics features were selected using Mann-Whitney U test, univariate logistic regression analysis, and minimum redundancy maximum relevance (MRMR) method. Random forest (RF) method was used to construct the radiomics model, and 10-times leave group out cross-validation (LGOCV) method was used to validate the robustness and reproducibility of the model. RESULTS: A total of 792 radiomics features (396 from late arterial phase and 396 from portal venous phase) were extracted from the ROI for each patient using Analysis Kit software. Nine most important and predictive features were selected using Mann-Whitney U test, univariate logistic regression analysis, and MRMR method. RF method was used to construct the radiomics model with the nine most predictive radiomics features, which showed a high discriminative ability with 97.7% accuracy, 97.6% sensitivity, 97.8% specificity, 98.4% positive predictive value, and 96.8% negative predictive value. The radiomics model was proved to be robust and reproducible using 10-times LGOCV method with an average area under the curve of 0.75 by the average performance of the 10 newly built models. CONCLUSION: The radiomics model based on CT could serve as a promising non-invasive method in differential diagnosis between early and late stage PDAC.

Efficacy of Huangqi Injection in the Treatment of Hypertensive Nephropathy: A Systematic Review and Meta-Analysis.

Background: Huangqi injection (HQI) is the extract of Astragalus membranaceus (Fisch.) Bunge, which is widely used in the treatment of a variety of diseases in China. It is supposed to be an important adjuvant therapy for hypertensive nephropathy. Objective: To evaluate the efficacy of HQI combined with antihypertensive drugs in the treatment of hypertensive nephropathy. Materials and Methods: We systematically searched China National Knowledge Infrastructure (CNKI), Chinese Scientific Journals Database (VIP), Wanfang Knowledge Service Platform (WanfangData), Chinese Biomedical Database (CBM), EMBASE, PubMed and Cochrane Library from their inception to April 23st, 2021. All studies were independently screened by two auditors according to the inclusion and exclusion criteria. Randomized controlled trials comparing HQI in combination with antihypertensive drugs vs. antihypertensive drugs alone were extracted. Results: The meta-analysis included 15 studies involving 1,483 participants.The effect of HQI combined with antihypertensive drugs is better than that of antihypertensive drugs alone in regulating hypertensive nephropathy for reducing 24-h urinary total protein (24 h UTP) [WMD=-0.29, 95% CI (-0.40, -0.18), P = 0.000], microalbuminuria (mALB) [WMD = -17.04, 95% CI (-23.14, -10.94), P = 0.000], serum creatinine (SCr) [WMD = -40.39, 95% CI (-70.39, -10.39), P = 0.008], systolic blood pressure (SBP) [WMD = -9.50, 95% CI (-14.64, -4.37), P = 0.000], diastolic blood pressure (DBP) [WMD = -4.588, 95% CI (-6.036, -3.140), P = 0.000], cystatin-C (Cys-c) [WMD = -0.854, 95% CI (-0.99, -0.72), P = 0.000], blood urea nitrogen (BUN) [WMD = -4.155, 95% CI (-6.152, -2.157), P = 0.000]. Conclusion: The combination of HQI and antihypertensive drugs is more efficient in improving the related indexes of patients with hypertensive nephropathy than using antihypertensive drugs alone, and a moderate dose of HQI (no more than 30 mL) may benefit more. However, the quality of the methodology is low and the number of samples is small, the results need to be confirmed by more stringent randomized controlled trials.

Mechanism of Abelmoschus manihot L. in the Treatment of Contrast-Induced Nephropathy on the Basis of Network Pharmacology Analysis.

Background: Contrast-induced nephropathy (CIN) is increasingly seen in patients receiving contrast medium. Abelmoschus manihot (L.) Medik. (Malvaceae) and its preparations are widely used and effective in the treatment of various chronic kidney diseases and CIN in China. It is supposed to be an important adjuvant therapy for CIN. Methods: PubMed and CNKI were searched for the main compounds of A. manihot L. The Swiss target prediction platform, OMIM, GeneCards, DisGeNET, and DrugBank databases were mined for information relevant to the prediction of targets that A. manihot L. in the treatment of CIN. Subsequently, STRING database was applied for the construction of the PPI protein interaction network, meanwhile, the core targets were screened. DAVID database was used to perform the GO function and Kegg signal pathway enrichment analysis. AutoDockTools and PYMOAL were used for molecular docking. Vitro experiments were used to verify the effect of TFA, the main active component of A. manihot L., in the intervention of iopromide-induced cells injury. Results: A total of 17 chemical components and 133 potential targets in A. manihot L. were obtained. The top 15 proteins with higher degree value were selected from the PPI network model, AKT1, PIK3R1, EGFR, SRC,AR, APP, TNF, GAPDH, MMP9, and PTPN1, etc. may be core targets. The enrichment analysis indicated that A. manihot L. was involved in the regulation of PI3K/AKT signaling pathway, FoxO signaling pathway, VEGF signaling pathway, HIF-1, TNF signaling pathway, melanoma, hepatitis B, and other signaling pathways which were mainly associated with the regulation of transcription and apoptosis, protein phosphorylation, inflammatory response, aging, and cell proliferation. Molecular docking indicated that the key components and core targets had a good binding ability. The vitro experiments illustrated that TFA reduces iopromide induced renal tubular cell injury and apoptosis, which may be related to regulating the phosphorylation of AKT. Conclusion: The study preliminarily revealed the multi-component, multi-target, and multi-pathway synergistic effects of A. manihot L. on CIN, which provide theoretical reference and basis for the study of the pharmacological mechanism of A. manihot L. in the treatment of CIN.

Qian Yang Yu Yin Granule Improves Renal Injury of Hypertension by Regulating Metabolic Reprogramming Mediated by HIF-1α/PKM2 Positive Feedback Loop.

Protection against hypoxia injury is an important therapeutic strategy for treating hypertensive nephropathy. In this study, the effects of Qian Yang Yu Yin granule (QYYY) on spontaneously hypertensive rats fed with high salt diet and HEK293T cells exposed to hypoxia were investigated. After eight weeks' treatment of QYYY, blood pressure, serum creatinine, serum cystatin C, blood urea nitrogen, urinary ß2-microglobulin, urinary N-acetyl-ß-glucosaminidase, and urinary microalbumin were assessed. The changes of hypoxia-inducible factor-1α (HIF-1α), pyruvate kinase M2 (PKM2), glucose transport 1 (GLUT1), lactate dehydrogenase A (LDH-A), connective tissue growth factor (CTGF), transforming growth factor-ß1 (TGF-ß1), ATP, lactate, pyruvate, and pathology were also assessed in vivo. HEK293T cells pre-treated with QYYY and/or HIF-1α over expressing cells were cultured in a three gas hypoxic incubator chamber (5% CO2, 1% O2, 94% N2) for 12 h and then the expressions of HIF-1α, PKM2, GLUT1, LDH-A, CTGF, TGF-ß1, ATP, lactate, and pyruvate were detected. Our results showed that QYYY promoted the indicators of renal inflammation and fibrosis mediated by HIF-1α/PKM2 positive feedback loop in vivo and vitro. Our findings indicated that QYYY treated hypertensive nephropathy by regulating metabolic reprogramming mediated by HIF-1α/PKM2 positive feedback loop.

Combined therapy of hypertensive nephropathy with ginkgo leaf extract and dipyridamole injection and antihypertensive drugs: A systematic review and meta-analysis.

BACKGROUND: In recent years, the incidence rate of hypertensive nephropathy has been increasing quickly, which has been a major threat to people's health. Renin-angiotensin-aldosterone system blockers have certain curative effects. However, there are some patients having serious adverse reactions, and the benefit population is limited, so the treatment of hypertensive renal damage is necessary to have beneficial supplement. More and more clinical studies have shown that ginkgo leaf extract and dipyridamole injection (GDI) combined with antihypertensive drugs has achieved good results in the treatment of hypertensive renal damage. It is supposed to be a supplementary treatment in hypertensive nephropathy. OBJECTIVES: To systematically assess the efficacy and safety of GDI combined with antihypertensive drugs on hypertensive renal injury. METHODS: Seven databases including PubMed, Cochrane Library, Embase, Wanfang database, China biomedical literature service system (Sino Med), VIP Chinese Sci-tech journal database (VIP), and China national knowledge internet (CNKI) were retrieved to collect randomized controlled trials (RCTs) in the experimental group containing combined therapy of hypertensive nephropathy with GDI and antihypertensive drugs. The retrieval time was from the establishment of database to July 8, 2020. Two researchers independently selected literature, extracted data, and evaluated the risk of bias in the study. The methodological quality was evaluated with Cochrane handbook and meta-analysis was performed with Stata 14.0 software. RESULTS: Eight studies were included in this study which involved 556 patients. The meta-analyses indicated that, compared with using antihypertensive drugs alone, combined treatment of GDI with antihypertensive drugs can decrease 24-hour urinary total protein (weighted mean difference [WMD] -0.61, 95% confidence interval [CI]: -0.82, -0.39; k = 6, P ≤ .001), blood urea nitrogen (WMD -1.27, 95% CI: -2.45, -0.10; k = 6, P = .033, serum creatinine (WMD -29.50, 95% CI: -56.44, -2.56; number of estimates [k] = 6, P = .032). CONCLUSIONS: Our meta-analyses showed that GDI combined with antihypertensive drugs can improve the renal function of hypertensive patients with renal injury.

Evaluation of contrast-enhanced computed tomography for the differential diagnosis of hypovascular pancreatic neuroendocrine tumors from chronic mass-forming pancreatitis.

PURPOSE: To assess the role of contrast-enhanced computed tomography (CECT) for differentiation of hypovascular pancreatic neuroendocrine tumors (hypo-PNETs) from chronic mass-forming pancreatitis (CMFP). METHODS: A retrospective study of 59 patients (27 hypo-PNETs patients vs 32 CMFP patients) who underwent preoperative CECT between July 2012 and July 2019 was performed. Qualitative and quantitative analysis was performed, including mass location, size, margin, cystic changes, calcification, pancreatic or bile duct dilatation, pancreatic atrophy, local vessels involvement, mass contrast enhancement and mass-to-pancreas enhancement ratio. Multivariate logistic regression analyses were used to identify relevant CT imaging findings in differentiation between hypo-PNETs and CMFP. RESULTS: When compared to CMFP, hypo-PNETs more frequently had a well-defined margin and cystic changes and less frequently had a history of pancreatitis and calcification. CMFP had higher mass contrast enhancement and mass-to-pancreas enhancement ratio in the portal and delayed phases than hypo-PNETs. After multivariate logistic regression analyses, areas under the curve (AUCs) were 0.795 (95 % CI: 0.652-0.899), 0.752 (95 % CI: 0.604-0.866), 0.859 (95 % CI: 0.726-0.943), and 0.929 (95 % CI: 0.814-0.983) for Model 1(clinical factors), Model 2 (qualitative parameters), Model 3 (quantitative parameters), and their combinations, respectively. CONCLUSION: Combined assessment of clinical factors, qualitative, and quantitative imaging characteristics can improve the differentiation between hypo-PNETs and CMFP at CECT.

Association Between ALDH-2 rs671 and Essential Hypertension Risk or Blood Pressure Levels: A Systematic Review and Meta-Analysis.

Background: The association between Aldehyde dehydrogenase II (ALDH-2) rs671 polymorphism and essential hypertension (EH) risk or blood pressure (BP) levels remains unclear. Objective: To systematically review the influence of the aldehyde dehydrogenase II rs671 polymorphism on essential hypertension risk and blood pressure levels. Methods: The PubMed, EMbase, Web of Science, Cochrane Library, CNKI and CBM databases were electronically searched to identify case-control or cohort studies published prior to July 2019 that examined the association between the rs671 polymorphism and the risk of essential hypertension or blood pressure levels. A meta-analysis was conducted with Stata 15.1 software. Results: Twenty-two articles were included. Among these articles, 20 incorporated 30 individual studies evaluating the association between the rs671 polymorphism and EH (11,051 hypertensive patients and 15,926 normotensive controls), and 8 incorporated 12 individual studies evaluating the association between the rs671 polymorphism and BP (20,512 subjects). The results of the meta-analysis showed that the mutation of the rs671 polymorphism was associated with a significantly decreased risk of EH in all models: allelic model (OR = 0.80, 95% CI: 0.73-0.87), homozygous model (OR = 0.71, 95% CI: 0.63-0.80), heterozygous model (OR = 0.79, 95% CI: 0.72-0.87), dominant model (OR = 0.79, 95% CI: 0.71-0.87), and recessive model (OR = 0.76, 95% CI: 0.68-0.85). In the stratified analyses, significant associations were found for males, drinkers and population-based studies. Simultaneously, the A carriers had lower SBP (WMD = -1.78, 95% CI: -3.02 to -0.53) and DBP (WMD = -1.09, 95% CI: -1.58 to -0.61) levels than individuals with the GG homozygote. Conclusion: The collective findings of this meta-analysis suggested that the ALDH-2 rs671 polymorphism represented an important genetic marker in the development of hypertension. Considering the overall quality of evidence and the relatively small pooled sample size, more well-conducted high-quality studies are required to verify the above conclusion. Systematic Review Registration Number: PROSPERO (CRD42019129746).

Danhong Injection for the Treatment of Hypertensive Nephropathy: A Systematic Review and Meta-Analysis.

OBJECTIVE: Danhong Injection (DHI) has been widely used to treat various diseases in China for many years. The objective of this systematic review was to evaluate the efficacy of DHI combined with antihypertensive drugs for treatment of hypertensive nephropathy. METHODS: Seven databases were searched from inception to September 21st, 2019. Randomized controlled trials comparing DHI combined with antihypertensive drugs versus antihypertensive drugs alone were extracted. The primary outcome was microalbuminuria (mALB). Secondary outcomes included systolic blood pressure (SBP), diastolic blood pressure (DBP), and serum creatinine (SCr). RESULTS: Fifteen studies were included in the meta-analysis, which indicated that DHI combined with antihypertensive drugs has advantages compared with antihypertensive drugs alone for reducing mALB [weighted mean difference (WMD) = -12.86, 95% confidence interval (CI) (-14.72, -11.0), P < 0.01], lowering SBP [WMD = -2.84, 95% CI (-4.56, -1.12), P = 0.001] and DBP [WMD = -2.38, 95% CI (-4.34, -0.43), P = 0.017], and decreasing SCr [WMD = -40.45, 95% CI (-55.69, -25.21), P < 0.01]. CONCLUSION: The combination of DHI with antihypertensive drugs appears to be more effective than antihypertensive drugs alone for treatment of hypertensive nephropathy. A moderate duration (≤4 weeks) of DHI administration is reasonable, and longer treatment with DHI should be avoided, according to the results of subgroup analysis.

The effects of gastrodin injection on hypertension: A systematic review and meta-analysis.

BACKGROUND: Hypertension is a common chronic disease and poses a huge burden to health care systems. Recent studies have shown that gastrodin injection (GI) has a potential supplementary therapeutic effect on hypertension. OBJECTIVES: To systematically assess the efficacy and safety of GI in treatment of hypertension. METHODS: Systematic search was conducted on 7 databases (PubMed, Cochrane Library, Embase, Wanfang database, China biomedical literature service system, VIP Chinese Sci-tech journal database and China national knowledge internet). The retrieval time was from the establishment of database to February 15, 2020. Two researchers independently selected literature, extracted data and evaluated the risk of bias in the study. The methodological quality was evaluated with Cochrane handbook. The meta-analysis was performed with Stata 14.0 software. RESULTS: Thirteen studies were included in this study involving 1525 patients. Compared with using conventional therapy alone, GI combined with conventional therapy can decrease systolic blood pressure (weighted mean difference [WMD] -6.67, 95% confidence interval [CI]: -10.30, -3.04. number of estimates [k] = 9, I = 89.3%), diastolic blood pressure (WMD -4.52, 95% CI: -7.79, -1.26. k = 9, I = 92.3%), and improve the clinical efficacy (relative risk [RR] 1.18, 95% CI: 1.10, 1.26. k = 6, I = 12.6%). CONCLUSIONS: The current evidence showed that GI combined with conventional therapy can improve systolic blood pressure, diastolic blood pressure and clinical efficacy. GI can become a supplementary treatment for hypertension.

Plant NLR immune receptor Tm-22 activation requires NB-ARC domain-mediated self-association of CC domain.

The nucleotide-binding, leucine-rich repeat-containing (NLR) class of immune receptors of plants and animals recognize pathogen-encoded proteins and trigger host defenses. Although animal NLRs form oligomers upon pathogen recognition to activate downstream signaling, the mechanisms of plant NLR activation remain largely elusive. Tm-22 is a plasma membrane (PM)-localized coiled coil (CC)-type NLR and confers resistance to Tobacco mosaic virus (TMV) by recognizing its viral movement protein (MP). In this study, we found that Tm-22 self-associates upon recognition of MP. The CC domain of Tm-22 is the signaling domain and its function requires PM localization and self-association. The nucleotide-binding (NB-ARC) domain is important for Tm-22 self-interaction and regulates activation of the CC domain through its nucleotide-binding and self-association. (d)ATP binding may alter the NB-ARC conformation to release its suppression of Tm-22 CC domain-mediated cell death. Our findings provide the first example of signaling domain for PM-localized NLR and insight into PM-localized NLR activation.

Arabidopsis formin 2 regulates cell-to-cell trafficking by capping and stabilizing actin filaments at plasmodesmata.

Here, we demonstrate that Arabidopsis thaliana Formin 2 (AtFH2) localizes to plasmodesmata (PD) through its transmembrane domain and is required for normal intercellular trafficking. Although loss-of-function atfh2 mutants have no overt developmental defect, PD's permeability and sensitivity to virus infection are increased in atfh2 plants. Interestingly, AtFH2 functions in a partially redundant manner with its closest homolog AtFH1, which also contains a PD localization signal. Strikingly, targeting of Class I formins to PD was also confirmed in rice, suggesting that the involvement of Class I formins in regulating actin dynamics at PD may be evolutionarily conserved in plants. In vitro biochemical analysis showed that AtFH2 fails to nucleate actin assembly but caps and stabilizes actin filaments. We also demonstrate that the interaction between AtFH2 and actin filaments is crucial for its function in vivo. These data allow us to propose that AtFH2 regulates PD's permeability by anchoring actin filaments to PD.

Cotton Leaf Curl Multan virus C4 protein suppresses both transcriptional and post-transcriptional gene silencing by interacting with SAM synthetase.

Gene silencing is a natural antiviral defense mechanism in plants. For effective infection, plant viruses encode viral silencing suppressors to counter this plant antiviral response. The geminivirus-encoded C4 protein has been identified as a gene silencing suppressor, but the underlying mechanism of action has not been characterized. Here, we report that Cotton Leaf Curl Multan virus (CLCuMuV) C4 protein interacts with S-adenosyl methionine synthetase (SAMS), a core enzyme in the methyl cycle, and inhibits SAMS enzymatic activity. By contrast, an R13A mutation in C4 abolished its capacity to interact with SAMS and to suppress SAMS enzymatic activity. Overexpression of wild-type C4, but not mutant C4R13A, suppresses both transcriptional gene silencing (TGS) and post-transcriptional gene silencing (PTGS). Plants infected with CLCuMuV carrying C4R13A show decreased levels of symptoms and viral DNA accumulation associated with enhanced viral DNA methylation. Furthermore, silencing of NbSAMS2 reduces both TGS and PTGS, but enhanced plant susceptibility to two geminiviruses CLCuMuV and Tomato yellow leaf curl China virus. These data suggest that CLCuMuV C4 suppresses both TGS and PTGS by inhibiting SAMS activity to enhance CLCuMuV infection in plants.

Hsp90 Interacts With Tm-22 and Is Essential for Tm-22-Mediated Resistance to Tobacco mosaic virus.

The tomato resistance gene Tm-22 encodes a coiled coil-nucleotide binding site-leucine rich repeat type resistance protein and confers effective immune response against tobamoviruses by detecting the presence of viral movement proteins (MPs). In this study, we show that the Nicotiana benthamiana Heat shock protein 90-kD (Hsp90) interacts with Tm-22. Silencing of Hsp90 reduced Tm-22-mediated resistance to Tobacco mosaic virus (TMV) and the steady-state levels of Tm-22 protein. Further, Hsp90 associates with SGT1 in yeast and in plant cells. These results suggest that Hsp90-SGT1 complex takes part in Tm-22-mediated TMV resistance by functioning as chaperone to regulate Tm-22 stability.

Antiviral Resistance Protein Tm-22 Functions on the Plasma Membrane.

The tomato Tobacco mosaic virus resistance-22 (Tm-22 ) gene encodes a coiled-coil-nucleotide binding site-Leu-rich repeat protein lacking a conventional plasma membrane (PM) localization motif. Tm-22 confers plant extreme resistance against tobamoviruses including Tobacco mosaic virus (TMV) by recognizing the avirulence (Avr) viral movement protein (MP). However, the subcellular compartment where Tm-22 functions is unclear. Here, we demonstrate that Tm-22 interacts with TMV MP to form a protein complex at the PM We show that both inactive and active Tm-22 proteins are localized to the PM When restricted to PM by fusing Tm-22 to the S-acylated PM association motif, the Tm-22 fusion protein can still induce a hypersensitive response cell death, consistent with its activation at the PM Through analyses of viral MP mutants, we find that the plasmodesmata (PD) localization of the Avr protein MP is not required for Tm-22 function. These results suggest that Tm-22-mediated resistance takes place on PM without requirement of its Avr protein to be located to PD.

Autophagy functions as an antiviral mechanism against geminiviruses in plants.

Autophagy is an evolutionarily conserved process that recycles damaged or unwanted cellular components, and has been linked to plant immunity. However, how autophagy contributes to plant immunity is unknown. Here we reported that the plant autophagic machinery targets the virulence factor ßC1 of Cotton leaf curl Multan virus (CLCuMuV) for degradation through its interaction with the key autophagy protein ATG8. A V32A mutation in ßC1 abolished its interaction with NbATG8f, and virus carrying ßC1V32A showed increased symptoms and viral DNA accumulation in plants. Furthermore, silencing of autophagy-related genes ATG5 and ATG7 reduced plant resistance to the DNA viruses CLCuMuV, Tomato yellow leaf curl virus, and Tomato yellow leaf curl China virus, whereas activating autophagy by silencing GAPC genes enhanced plant resistance to viral infection. Thus, autophagy represents a novel anti-pathogenic mechanism that plays an important role in antiviral immunity in plants.

CLCuMuB ßC1 Subverts Ubiquitination by Interacting with NbSKP1s to Enhance Geminivirus Infection in Nicotiana benthamiana.

Viruses interfere with and usurp host machinery and circumvent defense responses to create a suitable cellular environment for successful infection. This is usually achieved through interactions between viral proteins and host factors. Geminiviruses are a group of plant-infecting DNA viruses, of which some contain a betasatellite, known as DNAß. Here, we report that Cotton leaf curl Multan virus (CLCuMuV) uses its sole satellite-encoded protein ßC1 to regulate the plant ubiquitination pathway for effective infection. We found that CLCuMu betasatellite (CLCuMuB) ßC1 interacts with NbSKP1, and interrupts the interaction of NbSKP1s with NbCUL1. Silencing of either NbSKP1s or NbCUL1 enhances the accumulation of CLCuMuV genomic DNA and results in severe disease symptoms in plants. ßC1 impairs the integrity of SCFCOI1 and the stabilization of GAI, a substrate of the SCFSYL1 to hinder responses to jasmonates (JA) and gibberellins (GA). Moreover, JA treatment reduces viral accumulation and symptoms. These results suggest that CLCuMuB ßC1 inhibits the ubiquitination function of SCF E3 ligases through interacting with NbSKP1s to enhance CLCuMuV infection and symptom induction in plants.

FERONIA receptor kinase pathway suppresses abscisic acid signaling in Arabidopsis by activating ABI2 phosphatase.

Plant growth and development are controlled by a delicate balance of hormonal cues. Growth-promoting hormones and growth-inhibiting counterparts often antagonize each other in their action, but the molecular mechanisms underlying these events remain largely unknown. Here, we report a cross-talk mechanism that enables a receptor-like kinase, FERONIA (FER), a positive regulator of auxin-promoted growth, to suppress the abscisic acid (ABA) response through activation of ABI2, a negative regulator of ABA signaling. The FER pathway consists of a FER kinase interacting with guanine exchange factors GEF1, GEF4, and GEF10 that, in turn, activate GTPase ROP11/ARAC10. Arabidopsis mutants disrupted in any step of the FER pathway, including fer, gef1gef4gef10, or rop11/arac10, all displayed an ABA-hypersensitive response, implicating the FER pathway in the suppression mechanism. In search of the target for the FER pathway, we found that the ROP11/ARAC10 protein physically interacted with the ABI2 phosphatase and enhanced its activity, thereby linking the FER pathway with the inhibition of ABA signaling.