TRIM25 predominately associates with anti-viral stress granules.

Stress granules (SGs) are induced by various environmental stressors, resulting in their compositional and functional heterogeneity. SGs play a crucial role in the antiviral process, owing to their potent translational repressive effects and ability to trigger signal transduction; however, it is poorly understood how these antiviral SGs differ from SGs induced by other environmental stressors. Here we identify that TRIM25, a known driver of the ubiquitination-dependent antiviral innate immune response, is a potent and critical marker of the antiviral SGs. TRIM25 undergoes liquid-liquid phase separation (LLPS) and co-condenses with the SG core protein G3BP1 in a dsRNA-dependent manner. The co-condensation of TRIM25 and G3BP1 results in a significant enhancement of TRIM25's ubiquitination activity towards multiple antiviral proteins, which are mainly located in SGs. This co-condensation is critical in activating the RIG-I signaling pathway, thus restraining RNA virus infection. Our studies provide a conceptual framework for better understanding the heterogeneity of stress granule components and their response to distinct environmental stressors.

A phage nucleus-associated RNA-binding protein is required for jumbo phage infection.

Large-genome bacteriophages (jumbo phages) of the proposed family Chimalliviridae assemble a nucleus-like compartment bounded by a protein shell that protects the replicating phage genome from host-encoded restriction enzymes and DNA-targeting CRISPR-Cas nucleases. While the nuclear shell provides broad protection against host nucleases, it necessitates transport of mRNA out of the nucleus-like compartment for translation by host ribosomes, and transport of specific proteins into the nucleus-like compartment to support DNA replication and mRNA transcription. Here, we identify a conserved phage nuclear shell-associated protein that we term Chimallin C (ChmC), which adopts a nucleic acid-binding fold, binds RNA with high affinity in vitro, and binds phage mRNAs in infected cells. ChmC also forms phase-separated condensates with RNA in vitro. Targeted knockdown of ChmC using mRNA-targeting dCas13d results in accumulation of phage-encoded mRNAs in the phage nucleus, reduces phage protein production, and compromises virion assembly. Taken together, our data show that the conserved ChmC protein plays crucial roles in the viral life cycle, potentially by facilitating phage mRNA translocation through the nuclear shell to promote protein production and virion development.

The effectiveness of brief reminiscence-based psychosocial interventions for cancer patients: A systematic review and meta-analysis.

AIM: To determine the effectiveness of brief reminiscence-based psychosocial interventions in alleviating psychological distress in cancer patients. BACKGROUND: Cancer patients suffer tremendous psycho-spiritual pain, which affects their quality of life. Brief reminiscence-based psychosocial interventions have demonstrated positive effects on the mental health of cancer patients; however, the efficacy of these interventions has been inconsistent. DESIGN: A systematic review and meta-analysis. METHODS: This review was conducted and reported in accordance with the PRISMA 2020 checklist provided by the EQUATOR network. The Cochrane Library, Web of Science, PsycINFO, PubMed, Embase, CINAHL and Scopus databases were systematically searched from inception to 27 November 2022 to identify randomised controlled trials (RCTs) published in English. RESULTS: Twenty studies involving 1744 cancer participants were included. The meta-analysis showed statistically significant effects of brief reminiscence-based psychosocial interventions on hope, anxiety and depression at post-intervention. A separate analysis revealed that brief reminiscence-based psychosocial interventions had a sustainable effect on hope, spiritual well-being, anxiety and depression at 1 month after the intervention. However, no statistically significant effect on quality of life was found in our study either immediately after the intervention or at 1 month. CONCLUSIONS: Brief reminiscence-based psychosocial interventions can significantly reduce anxiety and depressive symptoms and improve hope and spiritual well-being in cancer patients. RELEVANCE TO CLINICAL PRACTICE: This study further supports that brief reminiscence-based psychosocial interventions should be incorporated into the routine care of cancer patients to address their psychosocial distress. PATIENT OR PUBLIC CONTRIBUTION: All authors of this article contributed to the study conception and design. All authors of the included studies provided original data for this paper.

Psoas muscle index and psoas muscle density are associated with functional status in patients with degenerative lumbar spinal stenosis.

BACKGROUND: The factors affecting lumbar spinal function in patients with degenerative lumbar spinal stenosis (DLSS) are still unclear. OBJECTIVE: This study explored psoas major muscle morphology in patients with DLSS and its association with their functional status. METHODS: A retrospective study was conducted on 288 patients with DLSS and 260 control subjects. Psoas major muscle evaluation included three morphometric parameters at the L3/4 disc level: psoas major index (PMI), muscle attenuation, and psoas major morphological changes (MPM). The association between psoas major morphology and functional status was assessed using the Oswestry disability index (ODI). RESULTS: Both female and male patients with DLSS had a higher PMI and lower muscle attenuation. PMI and muscle attenuation were inversely correlated with age in the DLSS group. After multivariable analyses, the PMI and psoas major muscle attenuation were positively correlated with patients' functional status. CONCLUSION: The PMI and muscle attenuation were positively correlated with functional status in patients with DLSS. These findings have important implications for physiotherapy programs of postoperative rehabilitation and conservative management of DLSS.

Development and external validation of a predictive model for prolonged length of hospital stay in elderly patients undergoing lumbar fusion surgery: comparison of three predictive models.

PURPOSE: This study aimed to develop a predictive model for prolonged length of hospital stay (pLOS) in elderly patients undergoing lumbar fusion surgery, utilizing multivariate logistic regression, single classification and regression tree (hereafter, "classification tree") and random forest machine-learning algorithms. METHODS: This study was a retrospective review of a prospective Geriatric Lumbar Disease Database. The primary outcome measure was pLOS, which was defined as the LOS greater than the 75th percentile. All patients were grouped as pLOS group and non-pLOS. Three models (including logistic regression, single-classification tree and random forest algorithms) for predicting pLOS were developed using training dataset and internal validation using testing dataset. Finally, online tool based on our model was developed to assess its validity in the clinical setting (external validation). RESULTS: The development set included 1025 patients (mean [SD] age, 72.8 [5.6] years; 632 [61.7%] female), and the external validation set included 175 patients (73.2 [5.9] years; 97[55.4%] female). Multivariate logistic analyses revealed that older age (odds ratio [OR] 1.06, p < 0.001), higher BMI (OR 1.08, p = 0.002), number of fused segments (OR 1.41, p < 0.001), longer operative time (OR 1.02, p < 0.001), and diabetes (OR 1.05, p = 0.046) were independent risk factors for pLOS in elderly patients undergoing lumbar fusion surgery. The single-classification tree revealed that operative time ≥ 232 min, delayed ambulation, and BMI ≥ 30 kg/m2 as particularly influential predictors for pLOS. A random forest model was developed using the remaining 14 variables. Intraoperative EBL, operative time, delayed ambulation, age, number of fused segments, BMI, and RBC count were the most significant variables in the final model. The predictive ability of our three models was comparable, with no significant differences in AUC (0.73 vs. 0.71 vs. 0.70, respectively). The logistic regression model had a higher net benefit for clinical intervention than the other models. The nomogram was developed, and the C-index of external validation for PLOS was 0.69 (95% CI, 0.65-0.76). CONCLUSION: This investigation produced three predictive models for pLOS in elderly patients undergoing lumbar fusion surgery. The predictive ability of our three models was comparable. Logistic regression model had a higher net benefit for clinical intervention than the other models. Our predictive model could inform physicians about elderly patients with a high risk of pLOS after surgery.

A phage nucleus-associated RNA-binding protein is required for jumbo phage infection.

Large-genome bacteriophages (jumbo phages) of the Chimalliviridae family assemble a nucleus-like compartment bounded by a protein shell that protects the replicating phage genome from host-encoded restriction enzymes and CRISPR/Cas nucleases. While the nuclear shell provides broad protection against host nucleases, it necessitates transport of mRNA out of the nucleus-like compartment for translation by host ribosomes, and transport of specific proteins into the nucleus-like compartment to support DNA replication and mRNA transcription. Here we identify a conserved phage nuclear shell-associated protein that we term Chimallin C (ChmC), which adopts a nucleic acid-binding fold, binds RNA with high affinity in vitro, and binds phage mRNAs in infected cells. ChmC also forms phase-separated condensates with RNA in vitro. Targeted knockdown of ChmC using mRNA-targeting dCas13d halts infections at an early stage. Taken together, our data suggest that the conserved ChmC protein acts as a chaperone for phage mRNAs, potentially stabilizing these mRNAs and driving their translocation through the nuclear shell to promote translation and infection progression.

Enhanced Recovery After Surgery (ERAS) Program for Anterior Cervical Discectomy and Fusion (ACDF) in Patients Over 60 Years Old.

Background: Enhanced recovery after surgery (ERAS) is currently widely used in many surgical specialties, but there is still a lack of concern about the cervical ERAS program for old patients (>60 years old). We aimed to determine whether our ERAS program significantly improved satisfaction and outcomes in old patients (>60 years old) with anterior cervical discectomy and fusion (ACDF). Methods: This is a retrospective cohort study. The study enrolled patients if they were over the age of 60 years old underwent ACDF from July 2019 and June 2021 (ERAS group) and from January 2018 and June 2019 (non-ERAS group). Data including demographic, comorbidity, and surgical information were collected. We also evaluated ERAS process compliance, primary outcome, surgical complication, and length of stay (LOS). Results: There were 135 patients in the ERAS group, and 122 patients in the non-ERAS group were included. A comparison of the demographic data revealed that there were no statistically significant intergroup differences observed between the group. Overall, ERAS pathway compliance was 91.9%. There were no significant differences in the fusion levels, operative time, intraoperative blood loss, postoperative VAS score, and complications between the ERAS and non-ERAS groups. In addition, there was no significant difference in readmission and mortality at 30-day follow-up between the two groups. However, we observed a statistically significant decrease in the LOS in the ERAS group (8.68±2.34 of ERAS group versus 10.43±4.05 in non-ERAS group, p=0.013). Conclusion: This report describes the first ERAS protocol used in old patients with ACDF. Our ERAS program is safe and associated with incremental benefits with respect to LOS in old patients with ACDF.

FAM91A1-TBC1D23 complex structure reveals human genetic variations susceptible for PCH.

Pontocerebellar hypoplasia (PCH) is a group of rare neurodevelopmental disorders with limited diagnostic and therapeutic options. Mutations in WDR11, a subunit of the FAM91A1 complex, have been found in patients with PCH-like symptoms; however, definitive evidence that the mutations are causal is still lacking. Here, we show that depletion of FAM91A1 results in developmental defects in zebrafish similar to that of TBC1D23, an established PCH gene. FAM91A1 and TBC1D23 directly interact with each other and cooperate to regulate endosome-to-Golgi trafficking of KIAA0319L, a protein known to regulate axonal growth. Crystal structure of the FAM91A1-TBC1D23 complex reveals that TBC1D23 binds to a conserved surface on FAM91A1 by assuming a Z-shaped conformation. More importantly, the interaction between FAM91A1 and TBC1D23 can be used to predict the risk of certain TBC1D23-associated mutations to PCH. Collectively, our study provides a molecular basis for the interaction between TBC1D23 and FAM91A1 and suggests that disrupted endosomal trafficking underlies multiple PCH subtypes.

Bibliometric analysis of research on neurodegenerative diseases and single-cell RNA sequencing: Opportunities and challenges.

Neurodegeneration, characterized by the progressive deterioration in neuronal structure or function, presents an elusive mechanism. The use of single-cell RNA sequencing (scRNA-seq) technology in the clinic is becoming increasingly prevalent in recent decades. This technology offers unparalleled cell-level insights into neurodegenerative diseases, establishing itself as a potent tool for elucidating these diseases underlying mechanisms. Here, we made a deep investigation for scRNA-seq research in neurodegenerative diseases using bibliometric analysis from 2009 to 2022. We observed a robust upward trajectory in the number of publications on this subject. The United States stood out as the principal contributor to this expanding field. Specifically, the University of California System exhibited notable research prowess in this field. Alzheimer disease and Parkinson disease were the diseases most frequently investigated. Key research hotspots include the creation of a molecular brain atlas and identification of vulnerable neuronal subpopulations and potential therapeutic targets at the transcriptomic level.

CrMP-Sol database: classification, bioinformatic analyses and comparison of cancer-related membrane proteins and their water-soluble variant designs.

Membrane proteins are critical mediators for tumor progression and present enormous therapeutic potentials. Although gene profiling can identify their cancer-specific signatures, systematic correlations between protein functions and tumor-related mechanisms are still unclear. We present here the CrMP-Sol database ( https://bio-gateway.aigene.org.cn/g/CrMP ), which aims to breach the gap between the two. Machine learning was used to extract key functional descriptions for protein visualization in the 3D-space, where spatial distributions provide function-based predictive connections between proteins and cancer types. CrMP-Sol also presents QTY-enabled water-soluble designs to facilitate native membrane protein studies despite natural hydrophobicity. Five examples with varying transmembrane helices in different categories were used to demonstrate the feasibility. Native and redesigned proteins exhibited highly similar characteristics, predicted structures and binding pockets, and slightly different docking poses against known ligands, although task-specific designs are still required for proteins more susceptible to internal hydrogen bond formations. The database can accelerate therapeutic developments and biotechnological applications of cancer-related membrane proteins.

Comparative efficacy of various exercise interventions on depression in older adults with mild cognitive impairment: A systematic review and network meta-analysis.

BACKGROUND: Exercise is a promising nonpharmacological treatment for improving depression in older adults with MCI, but it is unclear which exercises are most effective. The objectives of this study were to compare and rank the effectiveness of various exercise interventions for depression in mild cognitive impairment (MCI) and to investigate the effects of exercise on depression. METHODS: The PRISMA-NMA guidelines were applied to the development and reporting of review criteria. The Cochrane Library, Web of Science, PsycINFO, PubMed, EMBASE, CINAHL, and Scopus databases were systematically searched by combining search terms for randomized controlled trial studies (RCTs) published in English from individual databases with the earliest available date set to March 10, 2023. Two evaluators independently selected and evaluated eligible studies of changes in depression in older adults with MCI after an exercise intervention. A protocol for this systematic review was registered in PROSPERO (Registration number: CRD42022377052). RESULTS: A network meta-analysis was conducted on 15 eligible RCTs consisting of 4271 subjects, including aerobic (n = 6), mind-body (n = 6) and multicomponent (n = 3) exercise trials. Compared to controls, mind-body exercise showed the strongest improvement in depressive symptoms (SMD = -0.63, 95% CI: -1.13, -0.14), followed by aerobic (SMD = -0.57, 95% CI: -0.88, -0.26) and multicomponent exercise (SMD = -0.53, 95% CI: -1.02, -0.03). Notably, there were no statistically significant differences between exercise types: aerobic vs. mind-body (SMD = 0.06, 95% PrI: -0.71, 0.84), multicomponent vs. mind-body (SMD = 0.11, 95% PrI: -0.75, 0.97), or multicomponent vs. aerobic (SMD = 0.04, 95% PrI: -0.771, 0.86). CONCLUSIONS: In this review, we found that mind-body exercise was most effective when compared to conventional controls and that multiple exercise modalities (aerobic, mind-body, and multicomponent exercise) had beneficial and comparable effects in reducing depressive states in older adults with MCI. These findings may guide clinical geriatric stakeholders and allied health professionals in providing more scientifically optimal exercise prescriptions for older adults with MCI. In the future, more high-quality, long-term clinical trials are needed to support the exploration of longer-term dynamic effects.

Establishment of environment-sensitive probes targeting BRD3/BRD4 for imaging and therapy of tumor.

The BET (bromo and extra-terminal) family proteins are epigenetic readers and master transcription coactivators, which have attracted great interests as cancer therapeutic targets. However, there are few developed labeling toolkits that can be applied for the dynamic studies of BET family proteins in living cells and tissue slices. In order to label and study the distribution of the BET family proteins in tumor cells and tumor tissues, a novel series of environment-sensitive fluorescent probes (6a-6c) were designed and evaluated for their labeling properties. Interestingly, 6a is capable of identifying tumor tissue slices and making a distinction between the tumor and normal tissues. Moreover, it can localize to the nuclear bodies in tumor slices just like BRD3 antibody. In addition, it also played an anti-tumor role through the induction of apoptosis. All these features render 6a may compatible for immunofluorescent studies and future cancer diagnosis, and guide for the discovery of new anticancer drugs.

The association between low virulence organisms in different locations and intervertebral disc structural failure: A meta-analysis and systematic review.

Many factors may trigger intervertebral disc (IVD) structural failure (intervertebral disc degeneration (IDD) and endplate changes), including inflammation, infection, dysbiosis, and the downstream effects of chemical factors. Of these, microbial diversity in the IVD and elsewhere in the body has been considered as one of the potential reasons for disc structural failure. The exact relationships between microbial colonization and IVD structural failure are not well understood. This meta-analysis aimed to investigate the impact of microbial colonization and its location (such as skin, IVD, muscle, soft tissues, and blood) on IVD structural failure and corresponding low back pain (LBP) if any. We searched four online databases for potential studies. The potential relationships between microbial colonization in different sample sources (such as skin, IVD, muscle, soft tissues, and blood) and IDD and endplate change were considered as primary outcomes. Odds ratio (OR) and 95% confidence intervals (CI) for direct comparisons were reported. Grading of Recommendations Assessment, Development and Evaluation (GRADE) scale was used to assess the quality of evidence. Twenty-five cohort studies met the selection criteria. Overall pooled prevalence of microbial colonization in 2419 patients with LBP was 33.2% (23.6%-43.6%). The pooled prevalence of microbial colonization in 2901 samples was 29.6% (21.0%-38.9%). Compared with the patients without endplate change, the patients with endplate changes had higher rates of microbial colonization of disc (OR = 2.83; 95% CI = 1.93-4.14; I 2 = 37.6%; p = 0.108). The primary pathogen was Cutibacterium acnes which was present in 22.2% of cases (95% CI = 13.3%-32.5%; I 2 = 96.6%; p = 0.000). This meta-analysis and systematic review found low-quality grade evidence for an association between microbial colonization of disc with endplate changes. The primary pathogen was C. acnes. Due to lack of enough high-quality studies and methodological limitations of this review, further studies are required to improve our understanding of the potential relationships and mechanisms of microbiota, dysbiosis, IVD colonization and IVD structural failure.

Correlation of psoas major muscle morphology with function and clinical symptoms in patients with symptomatic multilevel lumbar spinal stenosis.

OBJECTIVE: This study was performed to quantify the morphological characteristics of the psoas major muscle in patients with symptomatic multilevel degenerative lumbar spinal stenosis (SMLSS) and assess the correlations of these morphological characteristics with function and clinical symptoms. METHODS: One hundred fourteen patients diagnosed with SMLSS (≥ 3 segments) were included. The patients' presenting symptoms were assessed with the Oswestry Disability Index (ODI), and visual analogue scale (VAS) scores were recorded. The morphology of the psoas major was evaluated at the L3/4 intervertebral disc level in three ways: by measuring (i) the psoas muscle mass index (PMI); (ii) the mean muscle attenuation (Hounsfield units, HU); and (iii) the morphologic change of the psoas major (mean ratios of the short axis to the long axis of the bilateral psoas major). RESULTS: Men had a higher PMI than women (p = 0.001). Patients with severe disability had a significantly lower PMI (p = 0.002) and muscle attenuation (p = 0.001). The PMI and muscle attenuation were significantly higher in the patients with no or mild back pain (both p < 0.001). In the univariable and multivariable analyses, a greater HU value was associated with a higher functional status as assessed by the ODI (p = 0.002), and a higher PMI was associated with less severe back pain as measured by the VAS score (p < 0.001). CONCLUSION: This study showed that muscle attenuation of psoas major positively correlated with the functional status and PMI negatively correlated with low back pain severity in patients diagnosed with SMLSS. Future prospective studies are needed to evaluate whether improvement in such muscle parameters through physiotherapy programs can alleviate the clinical symptoms and improve the functional status of patients with SMLSS.

Integrin ligands block mechanical signal transduction in baroreceptors.

Baroreceptors are nerve endings located in the adventitia of the carotid sinus and aortic arch. They act as a mechanoelectrical transducer that can sense the tension stimulation exerted on the blood vessel wall by the rise in blood pressure and transduce the mechanical force into discharge of the nerve endings. However, the molecular identity of mechanical signal transduction from the vessel wall to the baroreceptor is not clear. We discovered that exogenous integrin ligands, such as RGD, IKVAV, YIGSR, PHSRN, and KNEED, could restrain pressure-dependent discharge of the aortic nerve in a dose-dependent and reversible manner. Perfusion of RGD at the baroreceptor site in vivo can block the baroreceptor reflex. An immunohistochemistry study showed the binding of exogenous RGD to the nerve endings under the adventitia of the rat aortic arch, which may competitively block the binding of integrins to ligand motifs in extracellular matrix. These findings suggest that connection of integrins with extracellular matrix plays an important role in the mechanical coupling process between vessel walls and arterial baroreceptors.

Retrospective Data Analysis for Enhanced Recovery After Surgery (ERAS) Protocol for Elderly Patients with Long-Level Lumbar Fusion.

BACKGROUND: Enhanced recovery after surgery (ERAS) for spinal surgery is new; specifically, an ERAS program for elderly patients is lacking. Geriatric patients have special characteristics that result in further harm by surgical stress. ERAS interventions are designed to improve recovery after surgery and can result in substantial benefits in clinical outcomes and cost-effectiveness. We aimed to determine whether ERAS significantly improved satisfaction and outcomes in elderly patients with long-level lumbar fusion. METHODS: Patients >70 years old with lumbar disc herniation or lumbar spinal stenosis who underwent lumbar fusion of ≥3 levels from July 2019 to June 2021 (ERAS group) and from January 2018 to June 2019 (non-ERAS group) were enrolled. Demographic, comorbidity, and surgical data were collected from electronic medical records. ERAS interventions were categorized as preoperative, intraoperative, and postoperative. We also evaluated primary outcome, surgical complications, and length of stay (LOS). RESULTS: The study included 154 patients, 72 in the ERAS group and 82 case-matched patients in the non-ERAS group. Overall, ERAS pathway compliance was 91%. There were no significant differences in readmission and mortality rates at 30-day follow-up between the ERAS and non-ERAS groups. Statistically significant decreases were observed in the ERAS group in complications (6 in ERAS group vs. 19 in non-ERAS group, P = 0.013) and LOS (17.74 ± 5.56 days in ERAS group vs. 22.13 ± 12.21 days in non-ERAS group, P = 0.041). Multivariable linear regression showed that implementation of ERAS (P = 0.002) was correlated with LOS. Multivariable logistic regression showed that implementation of ERAS (P = 0.004) was correlated with complications. CONCLUSIONS: The ERAS protocol used in elderly patients after long-level lumbar fusion surgery was safe and associated with incremental benefits regarding complications and LOS.

Which sagittal evaluation system can effectively predict mechanical complications in the treatment of elderly patients with adult degenerative scoliosis? Roussouly classification or Global Alignment and Proportion (GAP) Score.

BACKGROUND: To achieve the proper sagittal alignment, previous studies have developed different assessment systems for adult degenerative scoliosis (ADS) which could help the spine surgeon in making treatment strategies. The purpose of our study is to evaluate whether Roussouly classification or global alignment and proportion (GAP) score is more appropriate in the prediction of mechanical complications after surgical treatment of ADS. METHODS: ADS patients who received long segmental fusion in the treatment during the period from December 2016 to December 2018 were evaluated in this study. Basic information and radiologic measurements were collected for analysis. Patients were divided into two groups according to occurrence or absence of mechanical complications for comparison. Mechanical complications included proximal junctional kyphosis (PJK), proximal junctional failure (PJF). GAP categories divided GAP score into proportioned spinopelvic position, moderately disproportioned position, and severely disproportioned position according to the cut-off values. The correlation between evaluation systems and mechanical complications was analyzed through a logistic regression model via stepwise backward elimination based on the Wald statistics. Receiver operator characteristic (ROC) curve was used to determine the predictability of the evaluation systems in the occurrence of mechanical complications and calculate their cut-off value. Area under the curve (AUC) was used to evaluate the validity of the thresholds. RESULTS: A total of 80 patients were included in this study. There were 41 patients in mechanical complication group and 39 patients in no mechanical complication group. GAP score (P = 0.008) and GAP categories (P = 0.007) were positively correlated with mechanical complications; Roussouly score was negatively correlated with mechanical complications (P = 0.034); GAP score was positively correlated with PJK (P = 0.021); Roussouly score was negatively correlated with implant-related complications (P = 0.018); GAP categories were correlated with implant loosening (P = 0.023). Results of ROC showed that GAP score was more effective in predicting PJK (AUC = 0.863) and PJF (AUC = 0.724) than Roussouly score; GAP categories (AUC = 0.561) was more effective than GAP score (AUC = 0.555) in predicting implant-related complications. CONCLUSIONS: Roussouly classification could only be a rough estimate of optimal spinopelvic alignment. Quantitative parameters in GAP score made it more effective in predicting mechanical complications, PJK and PJF than Roussouly classification.

ASIC2 Synergizes with TRPV1 in the Mechano-Electrical Transduction of Arterial Baroreceptors.

Mechanosensitive ion channels (MSCs) are key molecules in the mechano-electrical transduction of arterial baroreceptors. Among them, acid-sensing ion channel 2 (ASIC2) and transient receptor potential vanilloid subfamily member 1 (TRPV1) have been studied extensively and documented to play important roles. In this study, experiments using aortic arch-aortic nerve preparations isolated from rats revealed that both ASIC2 and TRPV1 are functionally necessary, as blocking either abrogated nearly all pressure-dependent neural discharge. However, whether ASIC2 and TRPV1 work in coordination remained unclear. So we carried out cell-attached patch-clamp recordings in HEK293T cells co-expressing ASIC2 and TRPV1 and found that inhibition of ASIC2 completely blocked stretch-activated currents while inhibition of TRPV1 only partially blocked these currents. Immunofluorescence staining of aortic arch-aortic adventitia from rats showed that ASIC2 and TRPV1 are co-localized in the aortic nerve endings, and co-immunoprecipitation assays confirmed that the two proteins form a compact complex in HEK293T cells and in baroreceptors. Moreover, protein modeling analysis, exogenous co-immunoprecipitation assays, and biotin pull-down assays indicated that ASIC2 and TRPV1 interact directly. In summary, our research suggests that ASIC2 and TRPV1 form a compact complex and function synergistically in the mechano-electrical transduction of arterial baroreceptors. The model of synergism between MSCs may have important biological significance beyond ASIC2 and TRPV1.

Biochemical and structural characterization of the BioZ enzyme engaged in bacterial biotin synthesis pathway.

Biotin is an essential micro-nutrient across the three domains of life. The paradigm earlier step of biotin synthesis denotes "BioC-BioH" pathway in Escherichia coli. Here we report that BioZ bypasses the canonical route to begin biotin synthesis. In addition to its origin of Rhizobiales, protein phylogeny infers that BioZ is domesticated to gain an atypical role of ß-ketoacyl-ACP synthase III. Genetic and biochemical characterization demonstrates that BioZ catalyzes the condensation of glutaryl-CoA (or ACP) with malonyl-ACP to give 5'-keto-pimeloyl ACP. This intermediate proceeds via type II fatty acid synthesis (FAS II) pathway, to initiate the formation of pimeloyl-ACP, a precursor of biotin synthesis. To further explore molecular basis of BioZ activity, we determine the crystal structure of Agrobacterium tumefaciens BioZ at 1.99 Å, of which the catalytic triad and the substrate-loading tunnel are functionally defined. In particular, we localize that three residues (S84, R147, and S287) at the distant bottom of the tunnel might neutralize the charge of free C-carboxyl group of the primer glutaryl-CoA. Taken together, this study provides molecular insights into the BioZ biotin synthesis pathway.