1.TGF-β1-engineered Biomimetic Platelet Nanoparticles for Targeted Therapy of Ischemic Stroke
Li-Qi CHEN ; Tian-Fang KANG ; Guo-Jun HUANG ; Ting YIN ; Ai-Qing MA ; Lin-Tao CAI ; Hong PAN
Progress in Biochemistry and Biophysics 2026;53(3):697-710
ObjectivePost-ischemic acute inflammation and the subsequent persistent dysregulation of the immune microenvironment represent major pathological drivers that aggravate neuronal injury and severely restrict functional recovery following ischemic stroke. Although current reperfusion therapies partially restore blood flow, they fail to effectively modulate the secondary inflammatory cascade and oxidative stress, which remain critical barriers to neurological restoration. To address this challenge, this study aimed to engineer and systematically evaluate a biomimetic nanosystem composed of transforming growth factor-β1 (TGF-β1)-loaded platelet membrane-camouflaged lipid nanoparticles (PLP). This nanosystem was designed to achieve dual lesion-targeted delivery and immune microenvironment remodeling. By verifying its spatiotemporal accumulation, anti-inflammatory activity, and neuroprotective efficacy, we sought to establish an integrated therapeutic strategy that simultaneously enables lesion targeting, immune regulation, and functional recovery after ischemic injury. MethodsThe physicochemical properties of PLP, including hydrodynamic particle size, zeta potential, structural stability, and morphology, were characterized using dynamic light scattering, zeta potential analysis, and transmission electron microscopy. The preservation of platelet membrane-derived adhesion and immunoregulatory proteins was confirmed by SDS-PAGE through comparative analysis of protein band profiles between PLP and native platelet membranes. The in vitro biological activities of PLP were evaluated using two complementary cellular models. LPS-induced M1-polarized RAW264.7 macrophages were employed to assess inflammatory modulation, while oxygen glucose deprivation/reperfusion (OGD/R)-induced BV2 microglial cells and SH-SY5Y neuronal cells were utilized to investigate neuroinflammatory regulation and neuronal protection. For in vivo validation, a transient middle cerebral artery occlusion (tMCAO) mouse model was established to mimic ischemia-reperfusion injury. The spatiotemporal biodistribution and lesion-targeting capability of the PLP were monitored through live fluorescence imaging. Therapeutic efficacy was comprehensively evaluated by triphenyltetrazolium chloride (TTC) staining, glial fibrillary acidic protein (GFAP) immunofluorescence analysis, body weight monitoring, and neurological severity score (NSS) assessment. ResultsPLP nanoparticles displayed a uniform spherical morphology, nanoscale particle size distribution, and stable negative surface charge, indicating favorable colloidal stability and circulation potential. SDS-PAGE results confirmed the effective retention of key platelet membrane proteins associated with endothelial adhesion, immune evasion, and inflammatory regulation, demonstrating the successful biomimetic construction. Optimal therapeutic concentrations were determined in OGD/R-induced BV2 cells, where PLP exhibited excellent cytocompatibility and anti-inflammatory activity.In vitro experiments demonstrated that PLP significantly inhibited the polarization of RAW264.7 macrophages toward the pro-inflammatory M1 phenotype and markedly reduced neuronal apoptosis under ischemia-reperfusion conditions. In vivo fluorescence imaging revealed that PLP rapidly accumulated in the ischemic brain hemisphere and maintained prolonged retention for up to 7 d, suggesting enhanced lesion-specific targeting and sustained drug release. Compared with control group, PLP treatment significantly reduced cerebral infarct volume, attenuated reactive astrogliosis, improved weight recovery, and accelerated neurological functional restoration, as reflected by significantly improved NSS scores. ConclusionThis study establishes a multifunctional biomimetic nanoplatform that integrates platelet membrane-mediated active targeting with the anti-inflammatory, antioxidative, and neuroprotective properties of TGF-β1. The PLP system enables rapid lesion homing and long-term retention while synergistically regulating the post-stroke inflammatory microenvironment by suppressing pro-inflammatory immune activation, reducing neuronal apoptosis, and limiting excessive astrocyte reactivity. Importantly, this study proposes a conceptually therapeutic paradigm that combines targeted delivery with immune microenvironment remodeling to achieve comprehensive neurovascular protection. These findings provide strong experimental evidence supporting the translational potential of biomimetic nanotherapeutics as next-generation precision interventions for ischemic stroke.
2.Noninvasive Screening for Chronic Atrophic Gastritis Using Photoplethysmography-derived Meridian-labelled Harmonic Parameters
Yun-Qing LE ; Jian-Xin CHEN ; Ai-Ping CHEN ; Zhi-Hong LI
Progress in Biochemistry and Biophysics 2026;53(5):1178-1194
ObjectiveChronic atrophic gastritis (CAG) is usually diagnosed by gastroscopy and histopathological biopsy. These procedures remain the reference standard, but their invasive nature and resource requirements may limit their use in large-scale population screening and repeated follow-up. A convenient and reproducible method for noninvasive auxiliary screening may help identify individuals who require further endoscopic assessment. Fingertip photoplethysmography (PPG) provides a noninvasive recording of peripheral pulse waves and allows harmonic features to be extracted from the signal. In this study, the so-called meridian-related variables were defined as PPG-derived harmonic parameters labelled according to meridian nomenclature, rather than as direct measurements of meridian physiology. This study aimed to compare these harmonic parameters between patients with CAG and non-CAG controls, identify parameters that remained different after age adjustment, and develop a multivariable model for noninvasive auxiliary screening and pre-endoscopic risk stratification of CAG. MethodsA total of 343 participants were included, comprising 171 patients with CAG and 172 non-CAG controls. CAG diagnosis was established using gastroscopy and histopathology as the reference standard. Fingertip PPG signals were collected using a PPG-based pulse acquisition device. Eight PPG-derived harmonic parameters labelled according to meridian nomenclature were extracted for analysis. Between-group differences were first assessed using nonparametric tests. Age-adjusted analyses were then performed to reduce potential confounding by age. The false discovery rate (FDR) method was applied for multiple-comparison correction. A multivariable logistic regression model integrating age and multiple harmonic parameters was constructed. Model performance was evaluated using receiver operating characteristic (ROC) analysis and the area under the curve (AUC). Internal validation performance was assessed using stratified five-fold cross-validation and bootstrap optimism correction. Threshold performance was examined using both a high-specificity strategy and a Youden index-based cutoff. Decision curve analysis was used to evaluate the model’s net clinical benefit across a range of threshold probabilities. ResultsAll eight harmonic parameters were non-normally distributed. In the univariate analysis, the stomach-labelled harmonic parameter (ST), bladder-labelled harmonic parameter (BL), and liver-labelled harmonic parameter (LR) differed between the CAG and non-CAG groups. After age adjustment and FDR correction, only ST and BL remained statistically significant. Compared with non-CAG controls, patients with CAG showed higher ST values and lower BL values. This finding indicates an associated differential harmonic pattern that was not fully explained by age distribution. However, the discriminative ability of a single harmonic parameter was limited. The best-performing single indicator was ST, with an AUC of 0.652 (95% CI: 0.595-0.707). The multivariable model integrating age and multiple harmonic parameters achieved an AUC of 0.791 (95% CI: 0.743-0.835), representing an improvement of 0.139 over ST alone. In internal validation, stratified five-fold cross-validation yielded a mean AUC of 0.753 (95% CI: 0.715-0.781), and the bootstrap optimism-corrected AUC was 0.748. These results suggest that the model retained moderate discriminative performance after internal validation.At a specificity of at least 95%, the model achieved a sensitivity of only 40.4% (95% CI: 25.7%-49.7%). This high-specificity cutoff may be suboptimal as the preferred threshold for an initial screening setting because of the potential risk of missed CAG cases. The Youden index-based optimal cutoff was 0.419, corresponding to a sensitivity of 80.7% and a specificity of 62.8%. This threshold may better match the practical aim of noninvasive auxiliary screening, where sensitivity is usually prioritized to reduce missed cases. Decision curve analysis showed that, within a threshold probability range of 10%-55%, the model provided higher net clinical benefit than the reference strategies of recommending gastroscopy for all participants or for none. ConclusionPatients with CAG showed associated harmonic differences in fingertip PPG-derived features, mainly characterized by higher ST and lower BL values after age adjustment and FDR correction. Compared with a single harmonic parameter, the multivariable model showed better overall discrimination and retained moderate internal validation performance. These findings suggest that PPG-derived harmonic parameters labelled according to meridian nomenclature may provide auxiliary information for noninvasive auxiliary screening and front-line triage before gastroscopic confirmation in CAG. The present results support further validation rather than immediate clinical implementation. External validation in independent, multicenter, and preferably prospective screening cohorts is needed to assess the model’s generalizability, screening performance, and potential clinical utility.
3.Noninvasive Screening for Chronic Atrophic Gastritis Using Photoplethysmography-derived Meridian-labelled Harmonic Parameters
Yun-Qing LE ; Jian-Xin CHEN ; Ai-Ping CHEN ; Zhi-Hong LI
Progress in Biochemistry and Biophysics 2026;53(5):1178-1194
ObjectiveChronic atrophic gastritis (CAG) is usually diagnosed by gastroscopy and histopathological biopsy. These procedures remain the reference standard, but their invasive nature and resource requirements may limit their use in large-scale population screening and repeated follow-up. A convenient and reproducible method for noninvasive auxiliary screening may help identify individuals who require further endoscopic assessment. Fingertip photoplethysmography (PPG) provides a noninvasive recording of peripheral pulse waves and allows harmonic features to be extracted from the signal. In this study, the so-called meridian-related variables were defined as PPG-derived harmonic parameters labelled according to meridian nomenclature, rather than as direct measurements of meridian physiology. This study aimed to compare these harmonic parameters between patients with CAG and non-CAG controls, identify parameters that remained different after age adjustment, and develop a multivariable model for noninvasive auxiliary screening and pre-endoscopic risk stratification of CAG. MethodsA total of 343 participants were included, comprising 171 patients with CAG and 172 non-CAG controls. CAG diagnosis was established using gastroscopy and histopathology as the reference standard. Fingertip PPG signals were collected using a PPG-based pulse acquisition device. Eight PPG-derived harmonic parameters labelled according to meridian nomenclature were extracted for analysis. Between-group differences were first assessed using nonparametric tests. Age-adjusted analyses were then performed to reduce potential confounding by age. The false discovery rate (FDR) method was applied for multiple-comparison correction. A multivariable logistic regression model integrating age and multiple harmonic parameters was constructed. Model performance was evaluated using receiver operating characteristic (ROC) analysis and the area under the curve (AUC). Internal validation performance was assessed using stratified five-fold cross-validation and bootstrap optimism correction. Threshold performance was examined using both a high-specificity strategy and a Youden index-based cutoff. Decision curve analysis was used to evaluate the model’s net clinical benefit across a range of threshold probabilities. ResultsAll eight harmonic parameters were non-normally distributed. In the univariate analysis, the stomach-labelled harmonic parameter (ST), bladder-labelled harmonic parameter (BL), and liver-labelled harmonic parameter (LR) differed between the CAG and non-CAG groups. After age adjustment and FDR correction, only ST and BL remained statistically significant. Compared with non-CAG controls, patients with CAG showed higher ST values and lower BL values. This finding indicates an associated differential harmonic pattern that was not fully explained by age distribution. However, the discriminative ability of a single harmonic parameter was limited. The best-performing single indicator was ST, with an AUC of 0.652 (95% CI: 0.595-0.707). The multivariable model integrating age and multiple harmonic parameters achieved an AUC of 0.791 (95% CI: 0.743-0.835), representing an improvement of 0.139 over ST alone. In internal validation, stratified five-fold cross-validation yielded a mean AUC of 0.753 (95% CI: 0.715-0.781), and the bootstrap optimism-corrected AUC was 0.748. These results suggest that the model retained moderate discriminative performance after internal validation.At a specificity of at least 95%, the model achieved a sensitivity of only 40.4% (95% CI: 25.7%-49.7%). This high-specificity cutoff may be suboptimal as the preferred threshold for an initial screening setting because of the potential risk of missed CAG cases. The Youden index-based optimal cutoff was 0.419, corresponding to a sensitivity of 80.7% and a specificity of 62.8%. This threshold may better match the practical aim of noninvasive auxiliary screening, where sensitivity is usually prioritized to reduce missed cases. Decision curve analysis showed that, within a threshold probability range of 10%-55%, the model provided higher net clinical benefit than the reference strategies of recommending gastroscopy for all participants or for none. ConclusionPatients with CAG showed associated harmonic differences in fingertip PPG-derived features, mainly characterized by higher ST and lower BL values after age adjustment and FDR correction. Compared with a single harmonic parameter, the multivariable model showed better overall discrimination and retained moderate internal validation performance. These findings suggest that PPG-derived harmonic parameters labelled according to meridian nomenclature may provide auxiliary information for noninvasive auxiliary screening and front-line triage before gastroscopic confirmation in CAG. The present results support further validation rather than immediate clinical implementation. External validation in independent, multicenter, and preferably prospective screening cohorts is needed to assess the model’s generalizability, screening performance, and potential clinical utility.
4.Polydatin Delays Progression of Colitis-associated Colorectal Cancer by Modulating IL-17A/Wnt/β-catenin Signaling Pathway
Jie LIU ; Mengmeng LYU ; Yanfei HONG ; Xinmei NAN ; Jialong SU ; Huachen LIU ; Qing WANG ; Guiying PENG
Chinese Journal of Experimental Traditional Medical Formulae 2026;32(13):144-154
ObjectiveTo investigate the effects and underlying mechanisms of polydatin in delaying the progression of colitis-associated colorectal cancer (CAC) by constructing an azoxymethane (AOM)/dextran sulfate sodium (DSS)-induced CAC mouse model and conducting in vitro experiments. MethodsFifty-four male C57BL/6J mice were randomly divided into normal, model, and polydatin groups (0.045 g·kg-1). The CAC mouse model was established using AOM/DSS, and samples were collected at 4, 7, and 10 weeks. Body weight change rate, disease activity index (DAI), and tumor formation were assessed. Hematoxylin-eosin (HE) staining was used to observe pathological injury in intestinal tissues. Immunohistochemistry (IHC) was performed to detect zonula occludens-1 (ZO-1) expression in colonic tissues, and Western blot was used to detect the expression of E-cadherin, N-cadherin, and Vimentin in colonic epithelial cells. Real-time PCR was used to measure mRNA expression of interleukin-17A (IL-17A), Wnt3a, β-catenin, T cell factor 1 (Tcf1), E-cadherin, N-cadherin, and Vimentin in colonic tissues. Flow cytometry was used to analyze the proportion of CD8+T cells and the expression of exhaustion-related molecules in tumors. Human colon cancer DLD-1 cells were cultured in a polydatin-containing medium, and wound healing assays were performed to observe migration changes. Real-time PCR was used to detect mRNA expression of interleukin-17 receptor A (IL-17RA), Wnt3a, β-catenin, Tcf1, E-cadherin, N-cadherin, and Vimentin in DLD-1 cells. ResultsCompared with the normal group, the model group at all three time points showed significantly decreased body weight change rate (P<0.01), significantly shortened colon length (P<0.01), and markedly increased DAI scores (P<0.01). HE staining revealed significant inflammatory cell infiltration in the submucosa of the colon in the model group, accompanied by epithelial dysplasia. ZO-1 expression in colonic tissues was significantly reduced (P<0.01). The mRNA expression of the pro-inflammatory factor IL-17A and key molecules of the Wnt/β-catenin pathway (Wnt3a, β-catenin, Tcf1) was significantly elevated (P<0.05). The mRNA and protein expression of epithelial-mesenchymal transition (EMT) markers N-cadherin and Vimentin was significantly upregulated (P<0.05), while E-cadherin expression was significantly downregulated (P<0.05). The proportion of tumor-infiltrating CD8+T cells expressing immunosuppressive molecules (TIM-3, LAG-3, PD-1) was significantly increased (P<0.05). Compared with the model group, the polydatin group showed significant improvement in body weight and DAI score (P<0.01), as well as recovery of colon length and tissue injury. ZO-1 expression in colonic tissue was significantly increased (P<0.01), while IL-17A, Wnt3a, β-catenin, Tcf1, N-cadherin, and Vimentin expression levels were significantly decreased (P<0.05), and E-cadherin expression was significantly increased (P<0.01). Tumor-infiltrating CD8+ T cells expressing immunosuppressive molecules were significantly reduced (P<0.05). In vitro experiments showed that polydatin significantly inhibited migration of DLD-1 cells (P<0.01) and reversed the upregulation of IL-17RA, Wnt3a, β-catenin, N-cadherin, and Vimentin mRNA, as well as the downregulation of E-cadherin mRNA (P<0.05). ConclusionPolydatin inhibits IL-17A secretion and IL-17RA expression, improves the immune microenvironment, blocks activation of the Wnt/β-catenin signaling pathway, suppresses EMT markers (N-cadherin and Vimentin), and restores tight junction protein expression in intestinal epithelial cells, thereby delaying the progression from colitis to colorectal cancer in mice.
5.The SMAD-Pathway Mediates HMGB1-Induced Proliferation and Metastatic Progression in Cutaneous Squamous Cell Carcinoma Cells
De-De LIAN ; Xue Mei LI ; Yu-Xi JIA ; Ming-Wei ZHOU ; Xiang-Ru CHEN ; Yang-Yang TIAN ; Min LI ; Ming-Hui SUN ; Ye ZHAO ; Hong-Jun LI ; Qing-Ling ZHANG
Annals of Dermatology 2026;38(1):51-58
Background:
High-mobility group box protein 1 (HMGB1) is a chromatin-binding protein involved in arthritis, ischemia, sepsis, atherosclerosis, neurodegenerative disorders, meningitis, and cancer. HMGB1 exhibits dual roles in cancer, acting as either a tumor suppressor or oncoprotein depending on context.
Objective:
This research aimed to elucidate HMGB1’s functional significance in cutaneous squamous cell carcinoma (cSCC).
Methods:
We overexpressed HMGB1 in cSCC cell lines using recombinant adenovirus and examined its effects on cell proliferation, colony formation, and cell migration.
Results:
Immunohistochemical analysis revealed elevated HMGB1 expression levels in cSCC tissue relative to normal epidermis. To assess the influence of HMGB1, we employed recombinant adenoviruses expressing HMGB1 to transduce SCC cell lines (SCC12 and SCC13). Enhanced HMGB1 expression significantly promoted cellular proliferation and colony formation capacity.Notably, HMGB1 overexpression elevated the levels of proliferation regulators, including P63, SOX2, CDK4 and CDK6. Furthermore, HMGB1 overexpression substantially enhanced tumor invasiveness, accompanied by upregulation of epithelial-mesenchymal transition (EMT) biomarkers. Mechanistically, overexpression of HMGB1 enhanced transforming growth factor-β signaling by increasing phosphorylation of SMAD2/3, the key mediators of EMT.
Conclusion
These data imply that HMGB1 acts as a tumor-promoting factor in cSCC.
6.Neither a Friend nor a Foe: An Unusual Case of Severe Symptomatic Hypercalcemia Secondary to Atypical Parathyroid Adenoma
Wye Hong Leong ; Qing Ci Goh ; Vanusha Devaraja Pillai ; Siow Ping Lee ; Maryam Ahmad Sharifuddin
Journal of the ASEAN Federation of Endocrine Societies 2026;41(S1):79-80
Introduction:
Atypical parathyroid adenoma (APA) constitutes approximately 0.5–4.0% of all cases of primary hyperparathyroidism (pHPT). Here, we report a case of APA
presenting with severe hypercalcemia, complicated with
renal impairment, bilateral medullary nephrocalcinosis,
and multiple fragility fractures.
Case:
A 45-year-old male initially presented with a 6-month
history of constipation, polyuria, lethargy, bone pain,
and difficulty in initiating micturition. Laboratory
investigations revealed impaired renal function with
an estimated glomerular filtration rate of 41.4 mL/min,
severe hypercalcemia (4.07 mmol/L), and an elevated
intact parathyroid hormone (iPTH) level of 104.0 pmol/L
(reference range: 1.58–6.03 pmol/L), confirming the
diagnosis of pHPT. He was also found to have vitamin D deficiency, with a serum total 25-hydroxyvitamin D level
of 46 nmol/L.
Ultrasound of the abdomen demonstrated bilateral
medullary nephrocalcinosis, while neck ultrasound and
Tc-99 m sestamibi parathyroid scintigraphy revealed a
concordant lesion in the posterior aspect of the left thyroid
lobe, suggestive of a parathyroid adenoma.
He returned 3 months later with closed fractures of the right
subtrochanteric femur and the right humerus following
a fall from standing height.
In view of persistent hypercalcemia despite hyperhydration and treatment with zoledronic acid, subcutaneous
denosumab (60 mg) was administered, resulting in an
improvement in serum calcium levels. A left inferior
parathyroidectomy was then performed concurrently
with internal fixation of the right femur. The surgery was
uneventful. Histopathological examination confirmed an
atypical parathyroid adenoma. Postoperatively, the serum
calcium and iPTH levels normalized, and the patient
remained asymptomatic and normocalcemic during
regular follow-up.
Conclusion
APA remains a diagnostic and therapeutic challenge due
to its clinical, biochemical, and histopathological features
of equivocal malignancy. Surgical resection remains
the mainstay of management of APA, and long-term
surveillance is essential in view of its uncertain malignant
potential and risk of recurrence.
Hypercalcemia
;
Parathyroid Neoplasms
7.Trimming and morphological identification of deposited tick specimens originating from 17 counties or cities in Yunnan Province
Zheng-xiang LIU ; Zong-ti SHAO ; Yu-qiong LI ; Qing-hong YUAN
Acta Parasitologica et Medica Entomologica Sinica 2026;33(3):204-209,225
Objective To characterize the species composition and distribution patterns of ticks in 17 counties and cities of Yunnan Province, thereby furnishing fundamental data for the prediction, prevention, and control of local tick-borne diseases. Methods Tick specimens deposited in Yunnan Institute of Endemic Disease Control and Prevention (YIEDC) collected from 17 counties or cities during 1957-2024 were thoroughly trimmed and morphological identified based on diagnostic characters. Results A total of 2 923 tick specimens were taxonomically identified and classified into 18 species within 6 genera in the Ixodidae family. Specifically, the genus Haemaphysalis comprised 6 species with 154 specimens, the genus Rhipicephalus included 3 species with 2 444 specimens, the genus Ixodes consisted of 4 species with 236 specimens, the genus Amblyomma included 3 species with 49 specimens, the genus Dermacentor contained 1 species with 12 specimens, and the genus Hyalomma included 1 species with 28 specimens. A wide range of host animals were found, including livestock, wild avian species, wild mammalian species, reptiles (including pythons), and humans. Conclusions Ticks were found on a wide array of host animals within the 17 counties and cities of Yunnan Province, demonstrating high host species diversity. Our data suggest a need to strengthen the monitoring of tick-borne diseases and provide health education for the general population in Yunnan Province.
8.Tasquinimod promotes the sensitivity of ovarian cancer cells to cisplatin by down-regulating the HDAC4/p21 pathway
Zhao LI ; Ya-Hong WU ; Ye-Qing GUO ; Xiao-Jia MIN ; Ying LIN
The Korean Journal of Physiology and Pharmacology 2025;29(2):191-204
To investigate whether Tasquinimod can influence cisplatin resistance in drug-resistant ovarian cancer (OC) cell lines by regulating histone deacetylase 4 (HDAC4) or p21, we explored its effects on the cell cycle, and associated mechanisms.RT-PCR and Western blot analyses, flow cytometry, CCK8 assay, and immunofluorescence were utilized to investigate the effects of Tasquinimod on gene expression, cell cycle, apoptosis, viability, and protein levels in OC cells. The results showed that Tasquinimod inhibited cell viability and promoted apoptosis in SKOV3/DDP (cisplatin) and A2780/DDP cells more effectively than DDP alone. In combination with cisplatin, Tasquinimod further enhanced cell apoptosis and reduced cell viability in these cell lines, an effect that could be reversed following HDAC4 overexpression. Tasquinimod treatment down-regulated HDAC4, Bcl-2, and cyclin D1, and CDK4 expression and up-regulated the cleaved-Caspase-3, and p21 expression in SKOV3/DDP and A2780/ DDP cells. Additionally, Tasquinimod inhibited DDP resistance in OC/DDP cells. These effects were similarly observed in OC mouse models treated with Tasquinimod. In conclusion, Tasquinimod can improve OC cells' sensitivity to DDP by down-regulating the HDAC4/p21 axis, offering insights into potential strategies for overcoming cisplatin resistance in OC.
9.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.
10.The Application of Spatial Resolved Metabolomics in Neurodegenerative Diseases
Lu-Tao XU ; Qian LI ; Shu-Lei HAN ; Huan CHEN ; Hong-Wei HOU ; Qing-Yuan HU
Progress in Biochemistry and Biophysics 2025;52(9):2346-2359
The pathogenesis of neurodegenerative diseases (NDDs) is fundamentally linked to complex and profound alterations in metabolic networks within the brain, which exhibit marked spatial heterogeneity. While conventional bulk metabolomics is powerful for detecting global metabolic shifts, it inherently lacks spatial resolution. This methodological limitation hampers the ability to interrogate critical metabolic dysregulation within discrete anatomical brain regions and specific cellular microenvironments, thereby constraining a deeper understanding of the core pathological mechanisms that initiate and drive NDDs. To address this critical gap, spatial metabolomics, with mass spectrometry imaging (MSI) at its core, has emerged as a transformative approach. It uniquely overcomes the limitations of bulk methods by enabling high-resolution, simultaneous detection and precise localization of hundreds to thousands of endogenous molecules—including primary metabolites, complex lipids, neurotransmitters, neuropeptides, and essential metal ions—directly in situ from tissue sections. This powerful capability offers an unprecedented spatial perspective for investigating the intricate and heterogeneous chemical landscape of NDD pathology, opening new avenues for discovery. Accordingly, this review provides a comprehensive overview of the field, beginning with a discussion of the technical features, optimal application scenarios, and current limitations of major MSI platforms. These include the widely adopted matrix-assisted laser desorption/ionization (MALDI)-MSI, the ultra-high-resolution technique of secondary ion mass spectrometry (SIMS)-MSI, and the ambient ionization method of desorption electrospray ionization (DESI)-MSI, along with other emerging technologies. We then highlight the pivotal applications of spatial metabolomics in NDD research, particularly its role in elucidating the profound chemical heterogeneity within distinct pathological microenvironments. These applications include mapping unique molecular signatures around amyloid β‑protein (Aβ) plaques, uncovering the metabolic consequences of neurofibrillary tangles composed of hyperphosphorylated tau protein, and characterizing the lipid and metabolite composition of Lewy bodies. Moreover, we examine how spatial metabolomics contributes to constructing detailed metabolic vulnerability maps across the brain, shedding light on the biochemical factors that render certain neuronal populations and anatomical regions selectively susceptible to degeneration while others remain resilient. Looking beyond current applications, we explore the immense potential of integrating spatial metabolomics with other advanced research methodologies. This includes its combination with three-dimensional brain organoid models to recapitulate disease-relevant metabolic processes, its linkage with multi-organ axis studies to investigate how systemic metabolic health influences neurodegeneration, and its convergence with single-cell and subcellular analyses to achieve unprecedented molecular resolution. In conclusion, this review not only summarizes the current state and critical role of spatial metabolomics in NDD research but also offers a forward-looking perspective on its transformative potential. We envision its continued impact in advancing our fundamental understanding of NDDs and accelerating translation into clinical practice—from the discovery of novel biomarkers for early diagnosis to the development of high-throughput drug screening platforms and the realization of precision medicine for individuals affected by these devastating disorders.


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