1.Expert Consensus on Neurocritical Care Monitoring and Management in Beijing and Tibet(2025)
Drolma PHURBU ; Wenjin CHEN ; Heng ZHANG ; Jian ZHANG ; Xiaomeng WANG ; Guoying LIN ; Wenjun PAN ; Xiying GUI ; Xin CAI ; Chodron TENZIN ; Jianlei FU ; Qianwei LI ; TSEYANG ; Yijun LIU ; Bo LIU ; Tsering DROLMA ; Yudron SONAM ; KYILV ; Samdrup TSERING ; Wa DA ; Juan GUO ; Cheng QIU ; Huan CHEN ; Xiaoting WANG ; Yangong CHAO ; Dawei LIU ; Wenzhao CHAI ; Chenggong HU ; Wanhong YIN ; Shihong ZHU
Medical Journal of Peking Union Medical College Hospital 2026;17(1):59-72
Neurocritical care involves complex pathophysiological mechanisms, and its incidence is higher, injuries are more severe, and treatment is more challenging in high-altitude environments. This consensus, based on the latest domestic and international evidence-based medical data, establishes a standardized, goal-oriented framework for neurocritical care management applicable in high-altitude regions and nationwide. The consensus was developed following international standards for evidence quality assessment and underwent two rounds of Delphi expert consultation, resulting in 32 recommendation statements covering three parts: management systems, monitoring and assessment, and core strategies. Key updates include: advocating for the establishment of independent neurocritical care units and implementing precise tiered diagnosis and treatment based on the "Five Differences in Critical Care" concept; constructing a "trinity" multimodal brain monitoring system centered on cerebral blood flow, cerebral oxygenation, and brain function, emphasizing routine bedside transcranial Doppler ultrasound, cerebral oximetry, and continuous electroencephalography monitoring; shifting management strategies from mild hypothermia therapy to targeted temperature management, and defining the "446" target management pathway for the supercritical stage; emphasizing the assessment of static and dynamic cerebrovascular autoregulation functions through multimodal methods to achieve individualized optimal mean arterial pressure management; elevating cerebrospinal fluid management goals to the level of "glymphatic system" function maintenance; implementing a multidisciplinary collaborative, whole-process management model focusing on patients' long-term neurological functional outcomes; de-escalation criteria include multidimensional indicators such as recovery of brain structure, restoration of cerebrovascular autoregulation, improvement in cerebrospinal fluid dynamics, and reduction in biomarker levels; and integrating cutting-edge technologies like artificial intelligence into post-critical care management and rehabilitation planning. This consensus systematically integrates the entire process of neurocritical care management, reflecting the modern connotation of goal-oriented, dynamic, and multimodal integration in neurocritical care medicine. It aims to adapt to new trends such as deepening understanding of pathophysiological mechanisms, the integration of medicine and engineering, and the empowerment of artificial intelligence, thereby further advancing the discipline of critical care medicine.
2.Effect of Wenpi Pills on lipid metabolism in mice with non-alcoholic fatty liver disease induced by various diets.
Chen-Fang ZHANG ; Kai LIU ; Chao-Wen FAN ; Mei-Ting TAI ; Xin ZHANG ; Rong ZHANG ; Qin-Wen CHEN ; Zun-Li KE
China Journal of Chinese Materia Medica 2025;50(10):2730-2739
The aim of this study was to investigate the improvement effect of Wenpi Pills(WPP) on non-alcoholic fatty liver disease(NAFLD). The experiment was divided into two parts, using C57BL/6 mouse models induced by a high-fat diet(HFD) and a methionine and choline deficiency diet(MCD). The HFD-induced experiment lasted for 16 weeks, while the MCD-induced experiment lasted for 6 weeks. Mice in both parts were divided into four groups: control group, model group, low-dose WPP group(3.875 g·kg~(-1), WPP_L), and high-dose WPP group(15.5 g·kg~(-1), WPP_H). After sample collection from the HFD-induced mice, lipid content in the serum and liver, liver function indexes in the serum, and hepatic pathology were examined. Real-time fluorescent quantitative reverse transcription PCR(qRT-PCR) was used to detect the expression of lipid-related genes. After sample collection from the MCD-induced mice, serum liver function indexes and inflammatory factors were measured, and hepatic pathology and lipid changes were analyzed by hematoxylin-eosin(HE) staining and widely targeted lipidomic profiling, respectively. The results from the HFD-induced experiment showed that, compared with the HFD group, WPP administration significantly reduced the levels of aspartate aminotransferase(AST), alanine aminotransferase(ALT), triglyceride(TG), and total cholesterol(TC) in the serum, with the WPP_H group showing the most significant improvement. HE staining results indicated that, compared with the HFD group, WPP treatment improved the morphology of white adipocytes, reducing their size, and alleviated hepatic steatosis and lipid droplet accumulation. The qRT-PCR results suggested that WPP might increase the mRNA expression of liver cholesterol-converting genes, such as liver X receptor α(LXRα) and cytochrome P450 family 27 subfamily A member 1(CYP27A1), as well as lipid consumption genes like peroxisome proliferator-activated receptor α(PPARα) and adenosine mono-phosphate-activated protein kinase(AMPK). Meanwhile, WPP decreased the mRNA expression of lipid synthesis genes, including fatty acid synthetase(FAS), stearoyl-CoA desaturase 1(SCD1), and sterol regulatory element-binding protein 1c(SREBP-1c), thereby reducing liver lipid accumulation. The results from the MCD-induced experiment showed that, compared with the MCD group, WPP administration reduced the levels of ALT, AST, and inflammatory factors in the serum, thereby alleviating liver injury and the inflammatory response. HE staining of liver tissue indicated that WPP effectively improved hepatic steatosis. Non-targeted lipidomics analysis showed that WPP improved lipid metabolism disorders in the liver, mainly by affecting the metabolism of TG and cholesterol esters. In conclusion, WPP can improve hepatic lipid accumulation in NAFLD mice induced by both HFD and MCD. This beneficial effect is primarily achieved by alleviating liver injury and inflammation, as well as regulating lipid metabolism.
Animals
;
Non-alcoholic Fatty Liver Disease/genetics*
;
Lipid Metabolism/drug effects*
;
Mice
;
Mice, Inbred C57BL
;
Drugs, Chinese Herbal/administration & dosage*
;
Male
;
Diet, High-Fat/adverse effects*
;
Liver/drug effects*
;
Humans
;
Disease Models, Animal
;
Methionine
3.Preparation of baicalin-berberine complex nanocrystal enteric microspheres and pharmacodynamic evaluation of ulcerative colitis treatment in rats.
Xiao-Chao HUANG ; Yi-Wen HU ; Peng-Yu SHEN ; Rui-Hong JIAN ; Dong-Li QI ; Zhi-Dong LIU ; Jia-Xin PI
China Journal of Chinese Materia Medica 2025;50(15):4263-4274
To enhance the therapeutic efficacy of the baicalin-berberine complex(BA-BBR) in the treatment of ulcerative colitis(UC), BA-BBR nanocrystal microspheres(BA-BBR NC MS) were prepared using the dropping method. The microspheres were characterized in terms of morphology, particle size, differential scanning calorimetry(DSC), and powder X-ray diffraction(XRD). The release profiles of BA and BBR from the microspheres were measured, and the drug release mechanism was investigated. A rat model of UC was induced by 5% dextran sodium sulfate(DSS) and treated continuously for 7 days to evaluate the therapeutic effects of different formulations. The results showed that the prepared BA-BBR MS and BA-BBR NC MS were uniform gel spheres with particle sizes of(1.77±0.16) mm and(1.67±0.08) mm, respectively. After drying, the gels collapsed inward and exhibited a rough surface. During the preparation process, the BA-BBR nanocrystals(BA-BBR NC) were uniformly encapsulated within the microspheres. The release profiles of the microspheres followed a first-order kinetic model, and the 12-hour cumulative release of BA and BBR from BA-BBR NC MS was higher than that from BA-BBR MS. Compared with BA-BBR, BA-BBR NC, and BA-BBR MS, BA-BBR NC MS further alleviated UC symptoms in rats, most significantly reducing the levels of TNF-α, IL-1β, IL-6, and MPO, while increasing the level of IL-4 in colon tissues. These results indicate that BA-BBR NC MS, based on a "nano-in-micro" design, can deliver BA-BBR to the intestine and exert significant therapeutic effects in a UC rat model, suggesting it as a promising new strategy for the treatment of UC.
Animals
;
Colitis, Ulcerative/metabolism*
;
Rats
;
Nanoparticles/chemistry*
;
Microspheres
;
Male
;
Berberine/administration & dosage*
;
Flavonoids/administration & dosage*
;
Rats, Sprague-Dawley
;
Drugs, Chinese Herbal/administration & dosage*
;
Humans
;
Particle Size
;
Tumor Necrosis Factor-alpha/immunology*
;
Drug Liberation
;
Drug Compounding
4.BiFC and FACS-based CRISPR screening revealed that QKI promotes PABPN1 LLPS in colorectal cancer cells.
Mengxia LI ; Zhijie HU ; Yingye HUANG ; Yuting HAN ; Cheng LIANG ; Yuchi LIU ; Runze WU ; Xin LU ; Ke DENG ; Susu LIU ; Xin OU ; Yuwei LI ; Chao LIU ; Xuening LI ; Jingting LIANG ; Yonggui FU ; Anlong XU
Protein & Cell 2025;16(7):557-574
Protein liquid-liquid phase separation (LLPS), a pivotal phenomenon intricately linked to cellular processes, is regulated by various other proteins. However, there is still a lack of high-throughput methods for screening protein regulators of LLPS in target proteins. Here, we developed a CRISPR/Cas9-based screening method to identify protein phase separation regulators by integrating bimolecular fluorescence complementation (BiFC) and fluorescence-activated cell sorting (FACS). Using this newly developed method, we screened the RNA-binding proteins that regulate PABPN1 phase separation and identified the tumor suppressor QKI as a promoter of PABPN1 phase separation. Furthermore, QKI exhibits decreased expression levels and diminished nuclear localization in colorectal cancer cells, resulting in reduced PABPN1 phase separation, which, in turn, promotes alternative polyadenylation (APA), cell proliferation, and migration in colorectal cancer.
Humans
;
Colorectal Neoplasms/genetics*
;
RNA-Binding Proteins/genetics*
;
Poly(A)-Binding Protein I/genetics*
;
CRISPR-Cas Systems
;
Flow Cytometry
;
Cell Proliferation
;
Cell Line, Tumor
;
Cell Movement
5.Aldolase A accelerates hepatocarcinogenesis by refactoring c-Jun transcription.
Xin YANG ; Guang-Yuan MA ; Xiao-Qiang LI ; Na TANG ; Yang SUN ; Xiao-Wei HAO ; Ke-Han WU ; Yu-Bo WANG ; Wen TIAN ; Xin FAN ; Zezhi LI ; Caixia FENG ; Xu CHAO ; Yu-Fan WANG ; Yao LIU ; Di LI ; Wei CAO
Journal of Pharmaceutical Analysis 2025;15(7):101169-101169
Hepatocellular carcinoma (HCC) expresses abundant glycolytic enzymes and displays comprehensive glucose metabolism reprogramming. Aldolase A (ALDOA) plays a prominent role in glycolysis; however, little is known about its role in HCC development. In the present study, we aim to explore how ALDOA is involved in HCC proliferation. HCC proliferation was markedly suppressed both in vitro and in vivo following ALDOA knockout, which is consistent with ALDOA overexpression encouraging HCC proliferation. Mechanistically, ALDOA knockout partially limits the glycolytic flux in HCC cells. Meanwhile, ALDOA translocated to nuclei and directly interacted with c-Jun to facilitate its Thr93 phosphorylation by P21-activated protein kinase; ALDOA knockout markedly diminished c-Jun Thr93 phosphorylation and then dampened c-Jun transcription function. A crucial site Y364 mutation in ALDOA disrupted its interaction with c-Jun, and Y364S ALDOA expression failed to rescue cell proliferation in ALDOA deletion cells. In HCC patients, the expression level of ALDOA was correlated with the phosphorylation level of c-Jun (Thr93) and poor prognosis. Remarkably, hepatic ALDOA was significantly upregulated in the promotion and progression stages of diethylnitrosamine-induced HCC models, and the knockdown of A ldoa strikingly decreased HCC development in vivo. Our study demonstrated that ALDOA is a vital driver for HCC development by activating c-Jun-mediated oncogene transcription, opening additional avenues for anti-cancer therapies.
6.Effects and mechanisms of swimming for inhibiting traumatic joint contracture in a rat model
Xiaoping SHUI ; Chunying LI ; Xin ZHANG ; Bin LI ; Chao FENG ; Hongyu ZHOU ; Ke CHEN ; Yingying LIAO
Chinese Journal of Tissue Engineering Research 2025;29(2):262-268
BACKGROUND:Early exercise treatment is the main prevention way for traumatic joint contracture and is also a research focus.Swimming may be a potential intervention for joint contracture due to the special physical properties of water. OBJECTIVE:To explore the effects of swimming on the development of joint contracture in a rat model and study its mechanisms. METHODS:Twenty-four Sprague-Dawley rats were randomly divided into a blank control group(n=8)and a joint contracture group(n=16).After the surgical operation of knee joint contracture rat models,the joint contracture group was randomly subdivided into a surgical control group(n=8)and a swimming treatment group(n=8).Swimming started in the swimming treatment group in the second week after surgery and lasted for a total of 5 weeks.At the 6th week after surgery,the body mass,knee joint range of motion,and quadriceps diameter were tested,and the diameter/body mass index was calculated.Hematoxylin-eosin staining was performed to detect the pathological changes in the knee joint capsule and quadriceps muscle,and Masson staining was used to observe fibrotic changes in the knee joint capsule.Furthermore,the protein expression of transforming growth factor β1 and type I collagen in the knee joint capsule was quantified by immunohistochemical assay and western blot was performed to detect the protein expression of MuRF1 in the quadriceps femoris. RESULTS AND CONCLUSION:Compared with the blank control group,the knee range of motion decreased in the surgical control and swimming treatment groups(P<0.01),and knee extension deficit and arthrogenic extension deficit were significantly increased(P<0.01),the diameter of the quadriceps muscle was decreased(P<0.01),the joint capsule showed significant fibrosis,the quadriceps muscle was atrophied,and the diameter/body mass index was decreased(P<0.01).Compared with the surgical control group,the swimming treatment group showed a significant increase in knee joint range of motion and quadriceps diameter(P<0.01),and significant improvement in joint capsule fibrosis and quadriceps atrophy.Compared with the blank control group,collagen fiber content and expression of transforming growth factor β1 and type I collagen were increased in the joint capsule of rats in both the surgical control group and the swimming treatment group(P<0.01).Compared with the surgical control group,collagen fiber content and expression of transforming growth factor β1 and type I collagen protein in the joint capsule were decreased in the swimming treatment group.Compared with the blank control group,the expression of MuRF1 protein in the quadriceps muscle of rats in the surgical control group and the swimming treatment group was increased(P<0.05).Compared with the surgical control group,the expression of MuRF1 protein in the quadriceps muscle of rats in the swimming treatment group was decreased(P<0.05).To conclude,early swimming intervention reduces transforming growth factor β1 and type I collagen expression in the joint capsule of traumatic joint contracture rats,decreases MuRF1 expression in the quadriceps muscle,and increases joint range of motion and quadriceps diameter,thereby inhibiting the development of joint contracture.
7.PDGF-C: an Emerging Target in The Treatment of Organ Fibrosis
Chao YANG ; Zi-Yi SONG ; Chang-Xin WANG ; Yuan-Yuan KUANG ; Yi-Jing CHENG ; Ke-Xin REN ; Xue LI ; Yan LIN
Progress in Biochemistry and Biophysics 2025;52(5):1059-1069
Fibrosis, the pathological scarring of vital organs, is a severe and often irreversible condition that leads to progressive organ dysfunction. It is particularly pronounced in organs like the liver, kidneys, lungs, and heart. Despite its clinical significance, the full understanding of its etiology and complex pathogenesis remains incomplete, posing substantial challenges to diagnosing, treating, and preventing the progression of fibrosis. Among the various molecular players involved, platelet-derived growth factor-C (PDGF-C) has emerged as a crucial factor in fibrotic diseases, contributing to the pathological transformation of tissues in several key organs. PDGF-C is a member of the PDGFs family of growth factors and is synthesized and secreted by various cell types, including fibroblasts, smooth muscle cells, and endothelial cells. It acts through both autocrine and paracrine mechanisms, exerting its biological effects by binding to and activating the PDGF receptors (PDGFRs), specifically PDGFRα and PDGFRβ. This binding triggers multiple intracellular signaling pathways, such as JAK/STAT, PI3K/AKT and Ras-MAPK pathways. which are integral to the regulation of cell proliferation, survival, migration, and fibrosis. Notably, PDGF-C has been shown to promote the proliferation and migration of fibroblasts, key effector cells in the fibrotic process, thus accelerating the accumulation of extracellular matrix components and the formation of fibrotic tissue. Numerous studies have documented an upregulation of PDGF-C expression in various fibrotic diseases, suggesting its significant role in the initiation and progression of fibrosis. For instance, in liver fibrosis, PDGF-C stimulates hepatic stellate cell activation, contributing to the excessive deposition of collagen and other extracellular matrix proteins. Similarly, in pulmonary fibrosis, PDGF-C enhances the migration of fibroblasts into the damaged areas of lungs, thereby worsening the pathological process. Such findings highlight the pivotal role of PDGF-C in fibrotic diseases and underscore its potential as a therapeutic target for these conditions. Given its central role in the pathogenesis of fibrosis, PDGF-C has become an attractive target for therapeutic intervention. Several studies have focused on developing inhibitors that block the PDGF-C/PDGFR signaling pathway. These inhibitors aim to reduce fibroblast activation, prevent the excessive accumulation of extracellular matrix components, and halt the progression of fibrosis. Preclinical studies have demonstrated the efficacy of such inhibitors in animal models of liver, kidney, and lung fibrosis, with promising results in reducing fibrotic lesions and improving organ function. Furthermore, several clinical inhibitors, such as Olaratumab and Seralutinib, are ongoing to assess the safety and efficacy of these inhibitors in human patients, offering hope for novel therapeutic options in the treatment of fibrotic diseases. In conclusion, PDGF-C plays a critical role in the development and progression of fibrosis in vital organs. Its ability to regulate fibroblast activity and influence key signaling pathways makes it a promising target for therapeutic strategies aiming at combating fibrosis. Ongoing research into the regulation of PDGF-C expression and the development of PDGF-C/PDGFR inhibitors holds the potential to offer new insights and approaches for the diagnosis, treatment, and prevention of fibrotic diseases. Ultimately, these efforts may lead to the development of more effective and targeted therapies that can mitigate the impact of fibrosis and improve patient outcomes.
8.Identification and Analysis of MHCⅡ Genes in Wuzhishan Pigs
Yuanyuan LIU ; Wenshui XIN ; Zhe CHAO ; Zongxi CAO ; Yifei CAI ; Qiang LI ; Lingwei LI ; Guangliang LIU
Laboratory Animal and Comparative Medicine 2025;45(3):340-348
ObjectiveTo obtain the gene sequences of major histocompatibility complex (MHC ) Ⅱgenes of Wuzhishan pigs, analyze their genetic information, and explore the biological functions of their MHC system. MethodsSpleen samples were collected from 3 adult male Wuzhishan pigs. Primers were designed according to MHCⅡ gene sequences, and the coding sequences of Wuzhishan pig MHCⅡ genes were amplified by RT-PCR. Sanger sequencing was performed to determine the full-length sequences. Bioinformatics tools were employed to analyze the physicochemical properties, phylogenetic relationships, conserved motifs, structural domains, chromosomal localization, and syntenic relationships of these genes. ResultsEight MHCⅡ genes were identified in Wuzhishan pigs, designated as SLA-DRA, SLA-DQA, SLA-DQB, SLA-DRB, SLA-DOB, SLA-DMB, SLA-DMA and SLA-DOA. The full-length sequences of these genes were determined by Sanger sequencing and subsequently deposited in GenBank under accession numbers PQ182796, PQ182797, PQ182798, PQ182799, PQ182800, PQ182801, PQ182802, and PQ164779. Phylogenetic analysis showed that the six MHCⅡ genes of Wuzhishan pigs clustered separately from their counterparts in Duroc, Meishan, Large White, and Bama pigs, indicating distinct evolutionary trajectories. Bioinformatics analysis demonstrated that most MHC Ⅱ proteins were hydrophobic, with molecular weights ranging from 27 700 to 30 000 Da. Genes within the same subregion shared conserved motifs. Specifically, four MHCⅡ proteins encoded by SLA-DQB, SLA-DRB, SLA-DOB, and SLA-DMB contained the MHCⅡβ conserved domain, while those encoded by the genes SLA-DRA, SLA-DQA, SLA-DMA, and SLA-DOA contained the MHCⅡα conserved domain. The eight MHCⅡ genes were scattered along the long arm of chromosome 7 in the Wuzhishan pigs, exhibiting syntenic relationships with three human genes and five Duroc pig genes. ConclusionThe MHCⅡ genes of Wuzhishan pigs may possess a unique evolutionary origin.
9.Identification and Analysis of MHCⅡ Genes in Wuzhishan Pigs
Yuanyuan LIU ; Wenshui XIN ; Zhe CHAO ; Zongxi CAO ; Yifei CAI ; Qiang LI ; Lingwei LI ; Guangliang LIU
Laboratory Animal and Comparative Medicine 2025;45(3):340-348
ObjectiveTo obtain the gene sequences of major histocompatibility complex (MHC ) Ⅱgenes of Wuzhishan pigs, analyze their genetic information, and explore the biological functions of their MHC system. MethodsSpleen samples were collected from 3 adult male Wuzhishan pigs. Primers were designed according to MHCⅡ gene sequences, and the coding sequences of Wuzhishan pig MHCⅡ genes were amplified by RT-PCR. Sanger sequencing was performed to determine the full-length sequences. Bioinformatics tools were employed to analyze the physicochemical properties, phylogenetic relationships, conserved motifs, structural domains, chromosomal localization, and syntenic relationships of these genes. ResultsEight MHCⅡ genes were identified in Wuzhishan pigs, designated as SLA-DRA, SLA-DQA, SLA-DQB, SLA-DRB, SLA-DOB, SLA-DMB, SLA-DMA and SLA-DOA. The full-length sequences of these genes were determined by Sanger sequencing and subsequently deposited in GenBank under accession numbers PQ182796, PQ182797, PQ182798, PQ182799, PQ182800, PQ182801, PQ182802, and PQ164779. Phylogenetic analysis showed that the six MHCⅡ genes of Wuzhishan pigs clustered separately from their counterparts in Duroc, Meishan, Large White, and Bama pigs, indicating distinct evolutionary trajectories. Bioinformatics analysis demonstrated that most MHC Ⅱ proteins were hydrophobic, with molecular weights ranging from 27 700 to 30 000 Da. Genes within the same subregion shared conserved motifs. Specifically, four MHCⅡ proteins encoded by SLA-DQB, SLA-DRB, SLA-DOB, and SLA-DMB contained the MHCⅡβ conserved domain, while those encoded by the genes SLA-DRA, SLA-DQA, SLA-DMA, and SLA-DOA contained the MHCⅡα conserved domain. The eight MHCⅡ genes were scattered along the long arm of chromosome 7 in the Wuzhishan pigs, exhibiting syntenic relationships with three human genes and five Duroc pig genes. ConclusionThe MHCⅡ genes of Wuzhishan pigs may possess a unique evolutionary origin.
10.Junctophilin-2 MORN-Helix Domain: Structural Basis for Membrane Binding and Hypertrophic Cardiomyopathy-associated Mutations
Jing-Xin WANG ; Zhi-Wei LI ; Wei LIU ; Wen-Qing ZHANG ; Jian-Chao LI
Progress in Biochemistry and Biophysics 2025;52(8):2103-2116
ObjectiveJunctophilin-2 (JPH2) is an essential structural protein that maintains junctional membrane complexes (JMCs) in cardiomyocytes by tethering the plasma membrane to the sarcoplasmic reticulum, thereby facilitating excitation-contraction (E-C) coupling. Mutations in JPH2 have been associated with hypertrophic cardiomyopathy (HCM), but the molecular mechanisms governing its membrane-binding properties and the functional relevance of its membrane occupation and recognition nexus (MORN) repeat motifs remain incompletely understood. This study aimed to elucidate the structural basis of JPH2 membrane association and its implications for HCM pathogenesis. MethodsA recombinant N-terminal fragment of mouse JPH2 (residues1-440), encompassing the MORN repeats and an adjacent helical region, was purified under near-physiological buffer conditions.X-ray crystallography was employed to determine the structure of the JPH2 MORN-Helix domain. Sequence conservation analysis across species and junctophilin isoforms was performed to assess the evolutionary conservation of key structural features. Functional membrane-binding assays were conducted using liposome co-sedimentation and cell-based localization studies in COS7 and HeLa cells. In addition, site-directed mutagenesis targeting positively charged residues and known HCM-associated mutations, including R347C, was used to evaluate their effects on membrane interaction and subcellular localization. ResultsThe crystal structure of the mouse JPH2 MORN-Helix domain was resolved at 2.6 Å, revealing a compact, elongated architecture consisting of multiple tandem MORN motifs arranged in a curved configuration, forming a continuous hydrophobic core stabilized by alternating aromatic residues. A C-terminal α-helix further reinforced structural integrity. Conservation analysis identified the inner groove of the MORN array as a highly conserved surface, suggesting its role as a protein-binding interface. A flexible linker segment enriched in positively charged residues, located adjacent to the MORN motifs, was found to mediate direct electrostatic interactions with negatively charged phospholipid membranes. Functional assays demonstrated that mutation of these basic residues impaired membrane association, while the HCM-linked R347C mutation completely abolished membrane localization in cellular assays, despite preserving the overall MORN-Helix fold in structural modeling. ConclusionThis study provides structural insight into the membrane-binding mechanism of the cardiomyocyte-specific protein JPH2, highlighting the dual roles of its MORN-Helix domain in membrane anchoring and protein interactions. The findings clarify the structural basis for membrane targeting via a positively charged linker and demonstrate that disruption of this interaction—such as that caused by the R347C mutation—likely contributes to HCM pathogenesis. These results not only enhance current understanding of JPH2 function in cardiac E-C coupling but also offer a structural framework for future investigations into the assembly and regulation of JMCs in both physiological and disease contexts.

Result Analysis
Print
Save
E-mail