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Background: The aim of this paper was to investigate the protein concentrations of high-temperature requirement A 1 (HTRA1) and transforming growth factor- β (TGF- β) in the vitreous humor of patients with chorioretinal vascular diseases. Methods: This study measured protein concentrations of HTRA1, TGF- β 1 − 3 , and vascular endothelial growth factor A (hereinafter called VEGF) in the vitreous humor from seven eyes of patients with chorioretinal vascular diseases (age-related macular degeneration, diabetic macular edema, and retinal vein occlusion) and six control eyes (idiopathic epiretinal membrane and macular hole). We analyzed the mutual relationship among the protein levels. Results: The protein levels of HTRA1 and VEGF were significantly increased in the chorioretinal vascular disease group compared with the control group (1.57 ± 0.79 × 10 − 9 mol/mL vs. 0.68 ± 0.79 × 10 − 9 mol/mL, p = 0.039; 3447.00 ± 3423.47 pg/mL vs. 35.33 ± 79.01 pg/mL, p = 0.046, respectively). TGF- β 2 levels were not significantly different between groups (2222.71 ± 1151.25 pg/mL for the chorioretinal vascular disease group vs. 1918.83 ± 744.01 pg/mL for the control group, p = 0.62). The concentration of HTRA1 was strongly associated with TGF- β 2 levels in the vitreous humor, independent of VEGF (r = 0.80, p = 0.0010). Conclusions: We revealed that vitreous HTRA1 was increased in patients with chorioretinal vascular diseases and strongly correlated with TGF- β 2 . [ABSTRACT FROM AUTHOR]

This article discusses a rare case of a 73-year-old man with a novel presentation of CADASIL type II, a hereditary cerebral arteriopathy. The man presented with gradually progressive choreiform movements and was diagnosed with vascular chorea. Genetic analysis revealed a heterozygous HTRA1 variant, confirming the diagnosis of CADASIL type II. The article provides information on the clinical features, neuroimaging findings, and genetic implications of CADASIL type II. [Extracted from the article]

Shina Song,1,2 Xiaofeng Li,1 Xuting Xue,3 Wenping Dong,2 Changxin Li1 1Department of Neurology, The First Hospital of Shanxi Medical University, Taiyuan, People’s Republic of China; 2Department of Geriatrics, General Hospital of TISCO, Taiyuan, People’s Republic of China; 3Shanxi Key Laboratory of Otorhinolaryngology Head and Neck Cancer, The First Hospital of Shanxi Medical University, Taiyuan, People’s Republic of ChinaCorrespondence: Wenping Dong, Department of Geriatrics, General Hospital of TISCO, North Street, Xinhualing District, Taiyuan, Shanxi Province, 030009, People’s Republic of China, Tel +86 13703581782, Email tgzyydwp@163.com Changxin Li, Department of Neurology, The First Hospital of Shanxi Medical University, Jiefangnan Road 85, Taiyuan, Shanxi Province, 030001, People’s Republic of China, Tel +86 13834635428, Email dslcxyx@126.comAbstract: High temperature requirement A1 (HTRA1) is a member of the serine protease family, comprising four structural domains: IGFBP domain, Kazal domain, protease domain and PDZ domain. HTRA1 encodes a serine protease, a secreted protein that is widely expressed in the vasculature. HTRA1 regulates a wide range of physiological processes through its proteolytic activity, and is also involved in a variety of vascular abnormalities-related diseases. This article reviews the role of HTRA1 in the development of vascular abnormalities-related hereditary cerebral small vessel disease (CSVD), age-related macular degeneration (AMD), tumors and other diseases. Through relevant research advances to understand the role of HTRA1 in regulating signaling pathways or refolding, translocation, degradation of extracellular matrix (ECM) proteins, thus directly or indirectly regulating angiogenesis, vascular remodeling, and playing an important role in vascular homeostasis, further understanding the mechanism of HTRA1’s role in vascular abnormality-related diseases is important for HTRA1 to be used as a therapeutic target in related diseases.Keywords: HTRA1, vascular anomalies, cerebral small vessel disease, AMD, tumor

Abstract Background The aberrant secretion and excessive deposition of type I collagen (Col1) are important factors in the pathogenesis of myocardial fibrosis in dilated cardiomyopathy (DCM). However, the precise molecular mechanisms underlying the synthesis and secretion of Col1 remain unclear. Methods and results RNA-sequencing analysis revealed an increased HtrA serine peptidase 1 (HTRA1) expression in patients with DCM, which is strongly correlated with myocardial fibrosis. Consistent findings were observed in both human and mouse tissues by immunoblotting, quantitative reverse transcription polymerase chain reaction (qRT-PCR), immunohistochemistry, and immunofluorescence analyses. Pearson’s analysis showed a markedly positive correlation between HTRA1 level and myocardial fibrosis indicators, including extracellular volume fraction (ECV), native T1, and late gadolinium enhancement (LGE), in patients with DCM. In vitro experiments showed that the suppression of HTRA1 inhibited the conversion of cardiac fibroblasts into myofibroblasts and decreased Col1 secretion. Further investigations identified the role of HTRA1 in promoting the formation of endoplasmic reticulum (ER) exit sites, which facilitated the transportation of Col1 from the ER to the Golgi apparatus, thereby increasing its secretion. Conversely, HTRA1 knockdown impeded the retention of Col1 in the ER, triggering ER stress and subsequent induction of ER autophagy to degrade misfolded Col1 and maintain ER homeostasis. In vivo experiments using adeno-associated virus-serotype 9-shHTRA1-green fluorescent protein (AAV9-shHTRA1-GFP) showed that HTRA1 knockdown effectively suppressed myocardial fibrosis and improved left ventricular function in mice with DCM. Conclusions The findings of this study provide valuable insights regarding the treatment of DCM-associated myocardial fibrosis and highlight the therapeutic potential of targeting HTRA1-mediated collagen secretion.

Background: The aberrant secretion and excessive deposition of type I collagen (Col1) are important factors in the pathogenesis of myocardial fibrosis in dilated cardiomyopathy (DCM). However, the precise molecular mechanisms underlying the synthesis and secretion of Col1 remain unclear. Methods and results: RNA-sequencing analysis revealed an increased HtrA serine peptidase 1 (HTRA1) expression in patients with DCM, which is strongly correlated with myocardial fibrosis. Consistent findings were observed in both human and mouse tissues by immunoblotting, quantitative reverse transcription polymerase chain reaction (qRT-PCR), immunohistochemistry, and immunofluorescence analyses. Pearson's analysis showed a markedly positive correlation between HTRA1 level and myocardial fibrosis indicators, including extracellular volume fraction (ECV), native T1, and late gadolinium enhancement (LGE), in patients with DCM. In vitro experiments showed that the suppression of HTRA1 inhibited the conversion of cardiac fibroblasts into myofibroblasts and decreased Col1 secretion. Further investigations identified the role of HTRA1 in promoting the formation of endoplasmic reticulum (ER) exit sites, which facilitated the transportation of Col1 from the ER to the Golgi apparatus, thereby increasing its secretion. Conversely, HTRA1 knockdown impeded the retention of Col1 in the ER, triggering ER stress and subsequent induction of ER autophagy to degrade misfolded Col1 and maintain ER homeostasis. In vivo experiments using adeno-associated virus-serotype 9-shHTRA1-green fluorescent protein (AAV9-shHTRA1-GFP) showed that HTRA1 knockdown effectively suppressed myocardial fibrosis and improved left ventricular function in mice with DCM. Conclusions: The findings of this study provide valuable insights regarding the treatment of DCM-associated myocardial fibrosis and highlight the therapeutic potential of targeting HTRA1-mediated collagen secretion. [ABSTRACT FROM AUTHOR]

Introduction: The aim of this study was to investigate the linkage disequilibrium (LD) and haplotype of three most associated SNP with nAMD of 80 patients in Indonesia. Methods: All patients underwent standard ophthalmic tests including fundoscopy and optical coherence tomography. Genomic DNA was extracted using commercially available DNA isolation kits. Genotyping of rs11200638, rs1061170 and del443ins54 used polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methods. The acquired genotype data were analyzed using Haploview and R package software. Results: Linkage Disequilibrium analyses showed high LD value in the 10q26 region of 80 patients with AMD and 85 controls. The PCR-RFLP showed TTA was the most frequent haplotype while GTG was the most associated haplotype in the study sample. Conclusion: There was a high LD in the 10q26 region and strong association in GTG haplotype of Indonesian patients with AMD. [ABSTRACT FROM AUTHOR]

Background: The infiltrative nature of human gliomas renders complete surgical removal of tumors futile. Thus, illuminating mechanisms of their infiltrative properties may improve therapies and outcomes of glioma patients. Methods: Comprehensive bioinformatic analyses of PRSS family were undertaken. Transfection of HTRA1 siRNAs was used to suppress HTRA1 expression. CCK‐8, EdU, and colony formation assay were employed to assess cell viability, and cell migration/invasion was detected by transwell, wound healing, and 3D tumor spheroid invasion assays. Immunoprecipitation was applied to study the mechanism that HTRA1 affected cell migration. In addition, in situ xenograft tumor model was employed to explore the role of HTRA1 in glioma growth in vivo. Results: HTRA1 knockdown could lead to suppression of cell viability, migration and invasion, as well as increased apoptosis. Immunoprecipitation results indicates HTRA1 might facilitate combination between HDAC6 and α‐tubulin to enhance cell migration by decreasing α‐tubulin acetylation. Besides, HTRA1 knockdown inhibited the growth of xenografts derived from orthotopic implantation of GBM cells and prolonged the survival time of tumor‐bearing mice. Conclusion: Our results indicate that HTRA1 promotes the proliferation and migration of GBM cells in vitro and in vivo, and thus may be a potential target for treatment in gliomas. [ABSTRACT FROM AUTHOR]

BACKGROUND: From the pathological mechanism of Western medicine, ligamentum flavum hypertrophy is the key pathogenic factor of lumbar spinal stenosis, and there is a lack of biological information on lumbar spinal stenosis of the Qi deficiency and blood stasis type. OBJECTIVE: To analyze and compare differential protein expression between hypertrophic and normal ligamentum flavum in patients with lumbar spinal stenosis of the Qi deficiency and blood stasis type. METHODS: Ligamentum flavum tissue samples were collected from six lumbar spinal stenosis patients with Qi deficiency and blood stasis, including three cases of ligamentum flavum hypertrophy (experimental group) and three cases of normal ligamentum flavum (control group). 4D Label free quantitative proteomic detection was performed to screen differentially expressed proteins. Gene oncology and Kyoto Encyclopedia of Genes and Genomes were used for enrichment analysis. RESULTS AND CONCLUSION: There were 183 differentially expressed proteins between the two groups, including 87 up-regulated and 96 down-regulated. Gene oncology enrichment analysis showed that biological processes mainly focused on cell processes, biological regulation and response to stimuli. Cell composition was concentrated in cell, intracellular, and protein-complex species. The main molecular functions included linkage, catalytic activity and molecular function regulator. The up-regulated proteins were mainly enriched to lysosomal signaling pathway, rheumatoid arthritis signaling pathway, and Staphylococcus aureus infection signaling pathway, while the down-regulated proteins were enriched to eight signaling pathways, namely p53 signaling pathway, renal cell carcinoma signaling pathway, transforming growth factor β signaling pathway, ubiquitin-mediated protein hydrolysis signaling pathway, Ca signaling pathway, cGMP-PKG signaling pathway, hypoxia-inducible factor 1 signaling pathway, and proteoglycan signaling pathway in cancer. INHBA, MMP14, TNC, HTRA1, FGF2 were the important differentially expressed proteins in the experimental group. To conclude, there are differential protein expressions between hypertrophic and normal ligamentum flavum in patients with Qi-stagnation and blood-stasis type lumbar spinal stenosis. INHBA may be the determinant of this disease, and its mechanism may be the activation of transforming growth factor β/Smad related signaling pathway, causing ligamentum flavum hypertrophy and subsequently leading to lumbar spinal stenosis. [ABSTRACT FROM AUTHOR]

INTRODUCTION: Cerebral small vessel disease (SVD) is common in patients with cognitive impairment and neurodegenerative diseases such as Alzheimer's and Parkinson's. This study investigated the burden of magnetic resonance imaging (MRI)‐based markers of SVD in patients with neurodegenerative diseases as a function of rare genetic variant carrier status. METHODS: The Ontario Neurodegenerative Disease Research Initiative study included 520 participants, recruited from 14 tertiary care centers, diagnosed with various neurodegenerative diseases and determined the carrier status of rare non‐synonymous variants in five genes (ABCC6, COL4A1/COL4A2, NOTCH3/HTRA1). RESULTS: NOTCH3/HTRA1 were found to significantly influence SVD neuroimaging outcomes; however, the mechanisms by which these variants contribute to disease progression or worsen clinical correlates are not yet understood. DISCUSSION: Further studies are needed to develop genetic and imaging neurovascular markers to enhance our understanding of their potential contribution to neurodegenerative diseases. [ABSTRACT FROM AUTHOR]

本文对1例60岁男性轻度认知障碍、头晕患者的临床症状、影像学和基因检测结果进行分析。该患者既往有高血压、高脂血症、高尿酸血症病史，以及长期吸烟、饮酒史，其母亲曾患痴呆，头颅MRI示多发腔隙性脑梗死、脑白质变性和多发微出血病灶，基因检测报告示HTRA1基因c.1174T>C杂合突变，以上结果符合HTRA1基因杂合突变相关遗传性脑小血管病的诊断。 Abstract: Clinical symptoms, imaging findings, and genetic testing results of a 60-year-old male patient with mild cognitive impairment and dizziness were analyzed. The patient had a history of hypertension, hyperlipidemia, hyperuricemia, and long-term smoking and alcohol consumption. His mother had dementia. Cranial magnetic resonance images revealed multiple lacunar infarctions, white matter degeneration, and multiple microbleeding lesions. Genetic testing report showed a heterozygous mutation in the HTRA1 gene (c.1174T > C). All of above results are consistent with the diagnosis of heterozygous HTRA1-related hereditary cerebral small vessel disease.

Abstract Background Age-related macular degeneration (AMD), characterized by the degeneration of retinal pigment epithelium (RPE) and photoreceptors, is the leading cause of irreversible vision impairment among the elderly. RPE senescence is an important contributor to AMD and has become a potential target for AMD therapy. HTRA1 is one of the most significant susceptibility genes in AMD, however, the correlation between HTRA1 and RPE senescence hasn’t been investigated in the pathogenesis of AMD. Methods Western blotting and immunohistochemistry were used to detect HTRA1 expression in WT and transgenic mice overexpressing human HTRA1 (hHTRA1-Tg mice). RT-qPCR was used to detect the SASP in hHTRA1-Tg mice and ARPE-19 cells infected with HTRA1. TEM, SA-β-gal was used to detect the mitochondria and senescence in RPE. Retinal degeneration of mice was investigated by fundus photography, FFA, SD-OCT and ERG. The RNA-Seq dataset of ARPE-19 cells treated with adv-HTRA1 versus adv-NC were analyzed. Mitochondrial respiration and glycolytic capacity in ARPE-19 cells were measured using OCR and ECAR. Hypoxia of ARPE-19 cells was detected using EF5 Hypoxia Detection Kit. KC7F2 was used to reduce the HIF1α expression both in vitro and in vivo. Results In our study, we found that RPE senescence was facilitated in hHTRA1-Tg mice. And hHTRA1-Tg mice became more susceptible to NaIO3 in the development of oxidative stress-induced retinal degeneration. Similarly, overexpression of HTRA1 in ARPE-19 cells accelerated cellular senescence. Our RNA-seq revealed an overlap between HTRA1-induced differentially expressed genes associated with aging and those involved in mitochondrial function and hypoxia response in ARPE-19 cells. HTRA1 overexpression in ARPE-19 cells impaired mitochondrial function and augmented glycolytic capacity. Importantly, upregulation of HTRA1 remarkably activated HIF-1 signaling, shown as promoting HIF1α expression which mainly located in the nucleus. HIF1α translation inhibitor KC7F2 significantly prevented HTRA1-induced cellular senescence in ARPE-19 cells, as well as improved the visual function in hHTRA1-Tg mice treated with NaIO3. Conclusions Our study showed elevated HTRA1 contributes to the pathogenesis of AMD by promoting cellular senescence in RPE through damaging mitochondrial function and activating HIF-1 signaling. It also pointed out that inhibition of HIF-1 signaling might serve as a potential therapeutic strategy for AMD. Video Abstract

The HtrA serine peptidase 1 (HTRA1) is a multidomain secretory protein with serine–protease activity involved in the regulation of many cellular processes in both physiological and pathological conditions. HTRA1 is normally expressed in the human placenta, and its expression is higher in the first trimester compared to the third trimester, suggesting an important role of this serine protease in the early phases of human placenta development. The aim of this study was to evaluate the functional role of HTRA1 in in vitro models of human placenta in order to define the role of this serine protease in preeclampsia (PE). BeWo and HTR8/SVneo cells expressing HTRA1 were used as syncytiotrophoblast and cytotrophoblast models, respectively. Oxidative stress was induced by treating BeWo and HTR8/SVneo cells with H2O2 to mimic PE conditions in order to evaluate its effect on HTRA1 expression. In addition, HTRA1 overexpression and silencing experiments were performed to evaluate the effects on syncytialization, cell mobility, and invasion processes. Our main data showed that oxidative stress significantly increased HTRA1 expression in both BeWo and HTR8/SVneo cells. In addition, we demonstrated that HTRA1 has a pivotal role in cell motility and invasion processes. In particular, HTRA1 overexpression increased while HTRA1 silencing decreased cell motility and invasion in HTR8/SVneo cell model. In conclusion, our results suggest an important role of HTRA1 in regulating extravillous cytotrophoblast invasion and motility during the early stage of placentation in the first trimester of gestation, suggesting a key role of this serine protease in PE onset.

Background: Osteoarthritis (OA) is a multifaceted chronic joint disease characterized by complex mechanisms. It has a detrimental impact on the quality of life for individuals in the middle-aged and elderly population while also imposing a significant socioeconomic burden. At present, there remains a lack of comprehensive understanding regarding the pathophysiology of OA. The objective of this study was to examine the genes, functional pathways, and immune infiltration characteristics associated with the development and advancement of OA. Methods: The Gene Expression Omnibus (GEO) database was utilized to acquire gene expression profiles. The R software was employed to conduct the screening of differentially expressed genes (DEGs) and perform enrichment analysis on these genes. The OA-characteristic genes were identified using the Weighted Gene Co-expression Network Analysis (WGCNA) and the Lasso algorithm. In addition, the infiltration levels of immune cells in cartilage were assessed using single-sample gene set enrichment analysis (ssGSEA). Subsequently, a correlation analysis was conducted to examine the relationship between immune cells and the OA-characteristic genes. Results: A total of 80 DEGs were identified. As determined by functional enrichment, these DEGs were associated with chondrocyte metabolism, apoptosis, and inflammation. Three OA-characteristic genes were identified using WGCNA and the lasso algorithm, and their expression levels were then validated using the verification set. Finally, the analysis of immune cell infiltration revealed that T cells and B cells were primarily associated with OA. In addition, Tspan2, HtrA1 demonstrated a correlation with some of the infiltrating immune cells. Conclusions: The findings of an extensive bioinformatics analysis revealed that OA is correlated with a variety of distinct genes, functional pathways, and processes involving immune cell infiltration. The present study has successfully identified characteristic genes and functional pathways that hold potential as biomarkers for guiding drug treatment and facilitating molecular-level research on OA. [ABSTRACT FROM AUTHOR]

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Inorganic arsenic (iAs) has been a human health concern and is associated with intestinal malignancies. However, the molecular mechanisms of the iAs‐induced oncogenic process in intestine epithelial cells remain elusive, partly because of the known hormesis effect of arsenic. Here, we established that six‐month exposure to iAs at a concentration similar to those found in contaminated drinking water could promote malignant characteristics, including enhanced proliferation and migration, resistance to apoptosis, and mesenchymal‐like transition in Caco‐2 cells. Transcriptome analysis and mechanism study revealed that key genes and pathways involved in cell adhesion, inflammation and oncogenic regulation were altered during chronic iAs exposure. Specifically, we uncovered that down‐regulation of HTRA1 was essential for the iAs‐induced acquisition of the cancer hallmarks. Further, we evidenced that the loss of HTRA1 during iAs‐exposure could be restored by HDAC6 inhibition. Caco‐2 cells with chronic exposure to iAs exhibited enhanced sensitivity to WT‐161, a specific inhibitor of HDAC6, when used alone than in combination with a chemotherapeutic agent. These findings provide valuable information for understanding the mechanisms of arsenic‐induced carcinogenesis and facilitating the health management of populations in arsenic‐polluted areas. This study explored the molecular mechanism associated with long‐term inorganic arsenic exposure in the colon epithelial Caco‐2 cell model. Our findings revealed that the down‐regulation of HTRA1 was essential for the malignant progression induced by chronic arsenic exposure, which could be restored by HDAC6 inhibition. These findings provide valuable information for understanding the key regulators of arsenic‐induced carcinogenesis. [ABSTRACT FROM AUTHOR]

Abstract Cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL) is an inherited cerebral small vessel disease (CSVD) caused by biallelic mutations in the high-temperature requirement serine peptidase A1 (HTRA1) gene. Even heterozygous mutations in HTRA1 are recently revealed to cause cardinal clinical features of CSVD. Here, we report the first establishment of a human induced pluripotent stem cell (hiPSC) line from a patient with heterozygous HTRA1-related CSVD. Peripheral blood mononuclear cells (PBMCs) were reprogrammed by the transfection of episomal vectors encoding human OCT3/4 (POU5F1), SOX2, KLF4, L-MYC, LIN28, and a murine dominant-negative mutant of p53 (mp53DD). The established iPSCs had normal morphology as human pluripotent stem cells and normal karyotype (46XX). Moreover, we found that the HTRA1 missense mutation (c.905G>A, p.R302Q) was heterozygous. These iPSCs expressed pluripotency-related markers and had the potential to differentiate into all three germ layers in vitro. HTRA1 and the supposed disease-associated gene NOG were differentially expressed in the patient iPSCs at mRNA levels compared to those of control lines. The iPSC line would facilitate in vitro research for understanding the cellular pathomechanisms caused by the HTRA1 mutation including its dominant-negative effect.

Background: Age-related macular degeneration (AMD), characterized by the degeneration of retinal pigment epithelium (RPE) and photoreceptors, is the leading cause of irreversible vision impairment among the elderly. RPE senescence is an important contributor to AMD and has become a potential target for AMD therapy. HTRA1 is one of the most significant susceptibility genes in AMD, however, the correlation between HTRA1 and RPE senescence hasn't been investigated in the pathogenesis of AMD. Methods: Western blotting and immunohistochemistry were used to detect HTRA1 expression in WT and transgenic mice overexpressing human HTRA1 (hHTRA1-Tg mice). RT-qPCR was used to detect the SASP in hHTRA1-Tg mice and ARPE-19 cells infected with HTRA1. TEM, SA-β-gal was used to detect the mitochondria and senescence in RPE. Retinal degeneration of mice was investigated by fundus photography, FFA, SD-OCT and ERG. The RNA-Seq dataset of ARPE-19 cells treated with adv-HTRA1 versus adv-NC were analyzed. Mitochondrial respiration and glycolytic capacity in ARPE-19 cells were measured using OCR and ECAR. Hypoxia of ARPE-19 cells was detected using EF5 Hypoxia Detection Kit. KC7F2 was used to reduce the HIF1α expression both in vitro and in vivo. Results: In our study, we found that RPE senescence was facilitated in hHTRA1-Tg mice. And hHTRA1-Tg mice became more susceptible to NaIO3 in the development of oxidative stress-induced retinal degeneration. Similarly, overexpression of HTRA1 in ARPE-19 cells accelerated cellular senescence. Our RNA-seq revealed an overlap between HTRA1-induced differentially expressed genes associated with aging and those involved in mitochondrial function and hypoxia response in ARPE-19 cells. HTRA1 overexpression in ARPE-19 cells impaired mitochondrial function and augmented glycolytic capacity. Importantly, upregulation of HTRA1 remarkably activated HIF-1 signaling, shown as promoting HIF1α expression which mainly located in the nucleus. HIF1α translation inhibitor KC7F2 significantly prevented HTRA1-induced cellular senescence in ARPE-19 cells, as well as improved the visual function in hHTRA1-Tg mice treated with NaIO3. Conclusions: Our study showed elevated HTRA1 contributes to the pathogenesis of AMD by promoting cellular senescence in RPE through damaging mitochondrial function and activating HIF-1 signaling. It also pointed out that inhibition of HIF-1 signaling might serve as a potential therapeutic strategy for AMD. F6p4cFd4Xy8hC-VtNmT8Qx Video Abstract [ABSTRACT FROM AUTHOR]

Late-onset retinal degeneration (L-ORD) is an autosomal dominant macular degeneration characterized by the formation of sub-retinal pigment epithelium (RPE) deposits and neuroretinal atrophy. L-ORD results from mutations in the C1q-tumor necrosis factor-5 protein (CTRP5), encoded by the CTRP5/C1QTNF5 gene. To understand the mechanism underlying L-ORD pathology, we used a human cDNA library yeast two-hybrid screen to identify interacting partners of CTRP5. Additionally, we analyzed the Bruch's membrane/choroid (BM-Ch) from wild-type (Wt), heterozygous S163R Ctrp5 mutation knock-in (Ctrp5S163R/wt ), and homozygous knock-in (Ctrp5S163R/S163R ) mice using mass spectrometry. Both approaches showed an association between CTRP5 and HTRA1 via its C-terminal PDZ-binding motif, stimulation of the HTRA1 protease activity by CTRP5, and CTRP5 serving as an HTRA1 substrate. The S163R-CTRP5 protein also binds to HTRA1 but is resistant to HTRA1-mediated cleavage. Immunohistochemistry and proteomic analysis showed significant accumulation of CTRP5 and HTRA1 in BM-Ch of Ctrp5S163R/S163R and Ctrp5S163R/wt mice compared with Wt. Additional extracellular matrix (ECM) components that are HTRA1 substrates also accumulated in these mice. These results implicate HTRA1 and its interaction with CTRP5 in L-ORD pathology.

Introduction: The aim of this study was to investigate the linkage disequilibrium (LD) and haplotype of three most associated SNP with nAMD of 80 patients in Indonesia. Methods: All patients underwent standard ophthalmic tests including fundoscopy and optical coherence tomography. Genomic DNA was extracted using commercially available DNA isolation kits. Genotyping of rs11200638, rs1061170 and del443ins54 used polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methods. The acquired genotype data were analyzed using Haploview and R package software. Results: Linkage Disequilibrium analyses showed high LD value in the 10q26 region of 80 patients with AMD and 85 controls. The PCR-RFLP showed TTA was the most frequent haplotype while GTG was the most associated haplotype in the study sample. Conclusion: There was a high LD in the 10q26 region and strong association in GTG haplotype of Indonesian patients with AMD. [ABSTRACT FROM AUTHOR]

Inflammation and elevated expression of high temperature requirement A serine peptidase 1 (HTRA1) are known high risk factors for age-related macular degeneration (AMD). However, the specific mechanism that HTRA1 causes AMD and the relationship between HTRA1 and inflammation remains unclear. We found that lipopolysaccharide (LPS) induced inflammation enhanced the expression of HTRA1, NF-κB, and p-p65 in ARPE-19 cells. Overexpression of HTRA1 up-regulated NF-κB expression, and on the other hand knockdown of HTRA1 down-regulated the expression of NF-κB. Moreover, NF-κB siRNA has no significant effect on the expression of HTRA1, suggesting HTRA1 works upstream of NF-κB. These results demonstrated that HTRA1 plays a pivotal role in inflammation, explaining possible mechanism of overexpressed HTRA1-induced AMD. Celastrol, a very common anti-inflammatory and antioxidant drug, was found to suppress inflammation by inhibiting phosphorylation of p65 protein efficaciously in RPE cells, which may be applied to the therapy of age-related macular degeneration. [ABSTRACT FROM AUTHOR]

Background: Heterozygous mutations in HTRA1 were recently found to cause autosomal dominant cerebral small vessel disease (CSVD), and it was named HTRA1-autosomal dominant disease (AD-HTRA1) in the consensus recommendations of the European Academy of Neurology. This study aimed to investigate the clinical features of a mutation in HTRA1 and the effect of HTRA1 mutation on white matter hyperintensity (WMH). Methods: A proband's brain magnetic resonance imaging (MRI) showed multiple lacunar infarctions and multiple WMH in the lateral ventricle, external capsule, frontal lobe and corpus callosum. The proband and family members were tested for CSVD-related genes by next-generation sequencing and the clinical data of the patients were collected. The published literature on AD-HTRA1 was collected, and the clinical characteristics and pathogenicity of the patients were summarized. Combined Annotation Dependent Depletion (CADD) is a tool for scoring the deleteriousness of single-nucleotide variants and insertion/deletion variants in the human genome. The relationship between the degree of WMH and the pathogenicity of the mutation was further analyzed. Result: It was found that the proband and her family members had a heterozygous missense mutation of c.854C > T (p.P285L) in the 4 exon of HTRA1 gene. A retrospective analysis of 5 families with c.854C > T mutation found that the patients had an early age of onset, cognitive impairment was more common, and alopecia and spondylosis could be combined at the same time. By univariate analysis, the severity of WMH was found to be significantly associated with the mutated CADD score (p < 0.05, Spearman's rho = 0.266). Conclusion: The clinical manifestations of AD-HTRA1 with mutation site c.854C > T (p.P285L) are similar to CARASIL, and brain MRI are mainly moderate or severe WMH and lacunar infarction (LI). WMH are affected by mutation sites. Therefore, our pathogenicity score for mutations can predict the severity of WMH. [ABSTRACT FROM AUTHOR]

Endplate osteochondritis is considered one of the major causes of intervertebral disc degeneration (IVDD) and low back pain. Menopausal women have a higher rate of endplate cartilage degeneration than similarly aged men, but the related mechanisms are still unclear. Subchondral bone changes, mainly mediated by osteoblasts and osteoclasts, are considered an important reason for the degeneration of cartilage. This work explored the role of osteoclasts in endplate cartilage degeneration, as well as its underlying mechanisms. A rat ovariectomy (OVX) model was used to induce estrogen deficiency. Our experiments indicated that OVX significantly promoted osteoclastogenesis and anabolism and catabolism changes in endplate chondrocytes. OVX osteoclasts cause an imbalance between anabolism and catabolism in endplate chondrocytes, as shown by a decrease in anabolic markers such as Aggrecan and Collagen II, and an increase in catabolic markers such as a disintegrin and metalloproteinase with thrombospondin motifs 5 (ADAMTS5) and matrix metalloproteinases (MMP13). Osteoclasts were also confirmed in this study to be able to secrete HtrA serine peptidase 1 (HTRA1), which resulted in increased catabolism in endplate chondrocytes through the NF-κB pathway under estrogen deficiency. This study demonstrated the involvement and mechanism of osteoclasts in the anabolism and catabolism changes of endplate cartilage under estrogen deficiency, and proposed a new strategy for the treatment of endplate osteochondritis and IVDD by targeting HTRA1.

Background: Stroke is the leading cause of mortality in China. DNA methylation has essential roles in multiple diseases, but its association with stroke was barely studied. We hereby explored the association between blood-based HTRA serine protease 1 (HTRA1) methylation and the risk of stroke. Results: The association was discovered in a hospital-based case–control study (cases/controls = 190:190) and further validated in a prospective nested case–control study including 139 cases who developed stroke within 2 years after recruitment and 144 matched stroke-free controls. We observed stroke-related altered HTRA1 methylation and expression in both case–control study and prospective study. This blood-based HTRA1 methylation was associated with stroke independently from the known risk factors and mostly affected the older population. The prospective results further showed that the altered HTRA1 methylation was detectable 2 years before the clinical determination of stroke and became more robust with increased discriminatory power for stroke along with time when combined with other known stroke-related variables [onset time ≤ 1 year: area under the curve (AUC) = 0.76]. Conclusions: In our study, altered HTRA1 methylation was associated with stroke at clinical and preclinical stages and thus may provide a potential biomarker in the blood for the risk evaluation and preclinical detection of stroke. [ABSTRACT FROM AUTHOR]

Background: Homozygous or compound heterozygous mutations in the high-temperature requirement A serine protease 1 gene (HTRA1) elicits cerebral autosomal recessive arteriopathy with subcortical infarcts and white matter lesions (CARASIL). The relationship between some heterozygous mutations, most of which are missense ones, and the occurrence of cerebral small vessel diseases (CSVD) has been reported. Recently, heterozygous HTRA1 nonsense mutations have been recognized to be pathogenic. Case presentation: We described two Chinese patients diagnosed with HTRA1-CSVD accompanied by heterozygous nonsense mutations. Their first clinical manifestations were symptoms due to ischemic stroke, and brain Magnetic Resonance Imaging (MRI) showed diffuse white matter lesions (WMLs) and microbleeds in both of them. Genetic sequencing revealed two novel heterozygous nonsense mutations: c.1096G>T (p.E366X) and c.151G>T (p.E51X). Conclusion: This case report expands the clinical, radiographic, and genetic spectrum of HTRA1-CSVD. Attention should be paid to young patients with ischemic stroke as the first clinical manifestation. Genetic screening for such sporadic CSVD is recommended, even if the symptoms are atypical. [ABSTRACT FROM AUTHOR]

Congenital cataract is the leading cause of blindness among children worldwide. Patients with posterior subcapsular congenital cataract (PSC) in the central visual axis can result in worsening vision and stimulus deprivation amblyopia. However, the pathogenesis of PSC remains unclear. This study aims to explore the functional regulation and mechanism of HTRA1 in human lens epithelial cells (HLECs). HTRA1 was significantly downregulated in the lens capsules of children with PSC compared to normal controls. HTRA1 is a suppression factor of transforming growth factor-β (TGF-β) signalling pathway, which plays a key role in cataract formation. The results showed that the TGF-β/Smad signalling pathway was activated in the lens tissue of PSC. The effect of HTRA1 on cell proliferation, migration and apoptosis was measured in HLECs. In primary HLECs, the downregulation of HTRA1 can promote the proliferation and migration of HLECs by activating the TGF-β/Smad signalling pathway and can significantly upregulate the TGF-β/Smad downstream target genes FN1 and α-SMA. HTRA1 was also knocked out in the eyes of C57BL/6J mice via adeno-associated virus-mediated RNA interference. The results showed that HTRA1 knockout can significantly upregulate p-Smad2/3 and activate the TGF-β/Smad signalling pathway, resulting in abnormal proliferation and irregular arrangement of lens epithelial cells and leading to the occurrence of subcapsular cataract. To conclude, HTRA1 was significantly downregulated in children with PSC, and the downregulation of HTRA1 enhanced the proliferation and migration of HLECs by activating the TGF-β/Smad signalling pathway, which led to the occurrence of PSC. [ABSTRACT FROM AUTHOR]

Background: The high-temperature requirement A 1 (HtrA1) is a multidomain secretory protein with serine-protease activity, expressed in many tissues, including placenta, where its expression is higher in the first trimester, suggesting an association of this serine protease in early phases of human placenta development. In this study, we evaluated maternal serum HtrA1 levels in the first and third trimester of gestation. In particular, we evaluated a possible role of HtrA1 as an early marker of gestational diabetes mellitus (GDM) in the first trimester of gestation. Methods: We evaluated HtrA1 serum levels in the third trimester (36–40 weeks) in normal pregnancies (n = 20) and GDM pregnancies (n = 20) by using ELISA analysis. Secondly, we performed the same analysis by using the first trimester sera (10–12 weeks) of healthy pregnant women that will develop a normal pregnancy (n = 210) or GDM (n = 28) during pregnancy. Results: We found that HtrA1 serum levels in the third trimester were higher in pregnancies complicated by GDM. Interestingly, higher HtrA1 serum levels were also found in the first trimester in women developing GDM later during the second–third trimester. No significant differences in terms of maternal age and gestational age were found between cases and controls. Women with GDM shown significantly higher pre-pregnancy BMI values compared to controls. Moreover, the probability of GDM occurrence significantly increased with increasing HtrA1 levels and BMI values. The ROC curve showed a good accuracy in predicting GDM, with an AUC of 0.74 (95%CI: 0.64–0.92). Conclusions: These results suggest an important role of HtrA1 as an early predictive marker of GDM in the first trimester of gestation, showing a significative clinical relevance for prevention of this disease. [ABSTRACT FROM AUTHOR]

Objective This study aimed at describing the frequency of rare variants of monogenic cerebral small vessel diseases (CSVD) in a cohort of patients with CSVD, and to explore its clinical relevance. Methods This study included CSVD patients visiting the Neurology Department of Peking Union Medical College Hospital(PUMCH) from March 2017 to January 2022, collecting their demographic and clinical information and DNA samples for whole-exome sequencing. Descriptive analysis and statistical analysis were conducted exploring the differences between monogenic CSVD-related gene mutation carriers and noncarriers. Results A total of 292 patients were included, 51.03% of whom carried one or more rare variants of monogenic CSVD-related genes. The most common rare low-frequency variants were located in the NOTCH3 gene (70 patients, 23.97%), followed by HTRA1 and COL4A1/COL4A2 (22 patients, 7.53%) respectively. Among the subgroup of patients without a family history of stroke (n=176), the frequency of rare variants was as high as 47.16%. Compared with non-carriers, the carriers were diagnosed at a younger age (58.76±13.71 vs. 63.46±13.21, P=0.003). No difference was found in phenotypes among single-SNP carriers, multiple-SNPs carriers, and noncarriers. Conclusions The frequency of rare mutation of monogenic CSVD-related genes were relatively high in Chinese CSVD cohort. The most common rare variant was within the NOTCH3, followed by HTRA1 and COL4A1/COL4A2 genes. For CSVD patients of unknown causes, genetic screening should not be neglected even if there is not a family history of the disease.

Priya Battu,1,* Kaushal Sharma,1,* Rajarathna Thangavel,2 Ramandeep Singh,3 Suresh Sharma,4 Vinod Srivastava,5 Akshay Anand1 1Neuroscience Research Lab, Department of Neurology, Post Graduate Institute of Medical Education and Research, Chandigarh, India; 2Department of Ophthalmology, Vasan Eye Care, Chennai, India; 3Advanced Eye Centre, Post Graduate Institute of Medical Education and Research, Chandigarh, India; 4Department of Statistics, Panjab University, Chandigarh, India; 5College of Health and Behavioral Sciences, Fort Hays State University, Hays, KS, USA*These authors contributed equally to this workCorrespondence: Akshay Anand, Neuroscience Research Lab, Department of Neurology, Post Graduate Institute of Medical Education and Research, Chandigarh, 160012, India, Tel +911722756094, Email akshay1anand@rediffmail.comBackground: Optical coherence tomography (OCT) parameters like subretinal fluid (SRF), intra retinal fluid (IRF) and retinal detachment (RPED) etc are routinely accessed by ophthalmologists in patients with retinal complaints. Correlation of OCT findings with genotype and phenotype of AMD patients is relatively unexplored. Here, we have investigated the association of OCT parameters’ with genetic variants along with protein expressions and examined their clinical relevance with AREDS (Age-Related Eye Disease Study) criteria in AMD patients.Methods: For this study, samples were recruited from Advanced Eye Centre, PGIMER, Chandigarh, India. Case-only analysis of anonymous imaging data (OCT/Fundus) acquired during the routine clinical evaluation of patients was done to examine the OCT findings in the AMD patients. TaqMan genotyping assays were used to analyze the single nucleotide polymorphisms in these patients. ELISA (enzyme linked immunosorbent assay) was used to estimate the protein levels of these genes in serum. Information pertaining to lifestyle/habits was also collected by administering a standard questionnaire at the time of recruitment of the patients.Results: Intra-retinal fluid (IRF) was associated significantly with the LIPC genotype (p=0.04). Similarly, smoking status and early AMD were also associated with the APOE genotype (p=0.03). Additionally, variants of IER-3 and SLC16A8 were also found to be associated with co-morbidities (p=0.02) and males (p=0.02), respectively. RPED has shown a significant association with AREDS criteria, which demonstrated an area under AUROC around 72%.Conclusion: Results of genotype–phenotype association can give a precise impression of AMD severity and can be beneficial for the early diagnosis of AMD cases.Keywords: age-related macular degeneration, RPE detachment, OCT parameters, TIMP-3, HTRA1, IPC, APOE, anti-VEGF therapy, AREDS

[Display omitted] High temperature requirement A serine peptidase 1 (HTRA1) is a serine protease involved in an array of signaling pathways. It is also responsible for the regulation of protein aggregates via refolding, translocation, and degradation. It has subsequently been found that runaway proteolytic HTRA1 activity plays a role in a variety of diseases, including Age-Related Macular Degeneration (AMD), osteoarthritis, and Rheumatoid Arthritis. Selective inhibition of serine protease HTRA1 therefore offers a promising new strategy for the treatment of these diseases. Herein we disclose structure–activity-relationship (SAR) studies which identify key interactions responsible for binding affinity of small molecule inhibitors to HTRA1. The study results in highly potent molecules with IC 50 ′s less than 15 nM and excellent selectivity following a screen of 35 proteases. [ABSTRACT FROM AUTHOR]

Abstract Cerebral amyloid angiopathy (CAA) is an age-related condition and a major cause of intracerebral hemorrhage and cognitive decline that shows close links with Alzheimer's disease (AD). CAA is characterized by the aggregation of amyloid-β (Aβ) peptides and formation of Aβ deposits in the brain vasculature resulting in a disruption of the angioarchitecture. Capillaries are a critical site of Aβ pathology in CAA type 1 and become dysfunctional during disease progression. Here, applying an advanced protocol for the isolation of parenchymal microvessels from post-mortem brain tissue combined with liquid chromatography tandem mass spectrometry (LC–MS/MS), we determined the proteomes of CAA type 1 cases (n = 12) including a patient with hereditary cerebral hemorrhage with amyloidosis-Dutch type (HCHWA-D), and of AD cases without microvascular amyloid pathology (n = 13) in comparison to neurologically healthy controls (n = 12). ELISA measurements revealed microvascular Aβ1-40 levels to be exclusively enriched in CAA samples (mean: > 3000-fold compared to controls). The proteomic profile of CAA type 1 was characterized by massive enrichment of multiple predominantly secreted proteins and showed significant overlap with the recently reported brain microvascular proteome of patients with cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), a hereditary cerebral small vessel disease (SVD) characterized by the aggregation of the Notch3 extracellular domain. We found this overlap to be largely attributable to the accumulation of high-temperature requirement protein A1 (HTRA1), a serine protease with an established role in the brain vasculature, and several of its substrates. Notably, this signature was not present in AD cases. We further show that HTRA1 co-localizes with Aβ deposits in brain capillaries from CAA type 1 patients indicating a pathologic recruitment process. Together, these findings suggest a central role of HTRA1-dependent protein homeostasis in the CAA microvasculature and a molecular connection between multiple types of brain microvascular disease.

Purpose: Age-relatedmacular degeneration (AMD) is a leading cause of vision loss. A Previous study based on the co-localization analysis of the genome-wide association study (GWAS) and eQTL genetic signals have reported that single nucleotide polymorphisms (SNPs), including rs760975, rs11528744, rs3761159, rs7212510, rs6965458, rs7559693, rs56108400, rs28495773, rs9928736, rs11777697, rs4381465 are associated with AMD in Americans. The aim of this studywas to investigate the association of these SNPs in a Han Chinese population. Methods: There were 576 patients with wet AMD and 572 healthy controls collected in this study. All SNPs were genotyped by flight mass spectrum. Hardy-Weinberg equilibrium was applied to evaluate allele distributions for both AMD and control groups. The genotype and allele frequencies were evaluated using the χ2 tests. Odds ratio (OR) and 95% confidence intervals (95% CI) were calculated for the risk of genotype and allele. Results: Three of the 11 SNPs (rs11528744 in HTRA1, rs9928736 in BCRA1 and rs4381465 in B3GLCT) were found to be significantly associated with AMD in the allelic model (corrected p = 0.001, OR = 1.391, 95%CI = 1.179-1.640 for rs11528744; corrected p = 0.004, OR = 0.695, 95%CI = 0.544-0.888 for rs9928736; corrected p = 0.002, OR = 0.614, 95%CI = 0.448-0.841 for rs4381465). There were no differences for the remaining eight SNPs between AMD cases and healthy controls. Conclusion: Our results showed that HTRA1 rs11528744, BCRA1 rs9928736, and B3GLCT rs4381465 were associated with wet AMD, suggesting that HTRA1, BCRA1, and B3GLCT genes may be involved in the development of AMD. [ABSTRACT FROM AUTHOR]

Background: Biallelic HTRA1 pathogenic variants are associated with autosomal recessive cerebral arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL). Recent studies have indicated that heterozygous HTRA1 variants are related to autosomal dominant hereditary cerebral small vessel disease (CSVD). However, few studies have assessed heterozygous HTRA1 carriers or the genotype–phenotype correlation. Methods: The clinical data of two unrelated Chinese Han families with CSVD were collected. Panel sequencing was used to search for pathogenic genes, Sanger sequencing was used for verification, three‐dimensional protein models were constructed, and pathogenicity was analyzed. Published HTRA1‐related phenotypes included in PubMed up to September 2021 were extensively reviewed, and the patients' genetic and clinical characteristics were summarized. Results: We report a novel heterozygous variant c.920T>C p.L307P in the HTRA1, whose main clinical and neuroimaging phenotypes are stroke and gait disturbance. We report another patient with the previously reported pathogenic variant HTRA1 c.589C>T p.R197X characterized by early cognitive decline. A literature review indicated that compared with CARASIL, HTRA1‐related autosomal dominant hereditary CSVD has a later onset age, milder clinical symptoms, fewer extraneurological symptoms, and slower progression, indicating a milder CARASIL phenotype. In addition, HTRA1 heterozygous variants were related to a higher proportion of vascular risk factors (p <.001) and male sex (p =.022). Conclusion: These findings broaden the known mutational spectrum and possible clinical phenotype of HTRA1. Considering the semidominant characteristics of HTRA1‐related phenotypes, we recommend that all members of HTRA1 variant families undergo genetic screening and clinical follow‐up if carrying pathogenic variants. [ABSTRACT FROM AUTHOR]

Background: Homozygous and compound heterozygous mutations in HTRA1 cause cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL). Recently, heterozygous pathogenic variants in HTRA1 were described in patients with autosomal dominant cerebral small vessel disease (CSVD). Here, we investigated the genetic variants in a cohort of Chinese patients with CSVD. Methods: A total of 95 Chinese index patients with typical characteristics of CSVD were collected. Whole exome sequencing was performed in the probands, followed by Sanger sequencing. Pathogenicity prediction software was applied to evaluate the pathogenicity of the identified variants. Results: We detected five heterozygous HTRA1 pathogenic variants in five index patients. These pathogenic variants included four known variants (c.543delT, c.854C>T, c.889G>A, and c.824C>T) and one novel variant (c.472 + 1G>A). Among them, c.854C>T, c.824C>T, and c.472 + 1G>A have never been reported in China and c.889G>A was once reported in homozygous but never in heterozygous. Three of them were distributed in exon 4, one in exon 2, and another splicing variant in intron 1. Four out of five probands presented typical features of CARASIL but less severe. The common clinical features included lacunar infarction, cognitive decline, alopecia, and spondylosis. All of them showed leukoencephalopathy, and the main involved cerebral area include periventricular and frontal area, centrum semiovale, thalamus, and corpus callosum. Anterior temporal lobes and external capsule involvement were also observed. Three probands had intracranial microbleeds. Conclusion: Our study expanded the mutation spectrum of HTRA1, especially in Chinese populations, and provided further evidence for “hot regions” in exon 1–4, especially in exon 4, in heterozygous HTRA1 pathogenic variants. Our work further supported that patients with heterozygous HTRA1 pathogenic variants presented with similar but less-severe features than CARASIL but in an autosomal dominantly inherited pattern. [ABSTRACT FROM AUTHOR]

Objectives: Proteolytic destruction of articular cartilage, a major pathogenic mechanism in osteoarthritis (OA), was not previously investigated by terminomics strategies. We defined the degradome of human knee OA cartilage and the contribution therein of the protease HtrA1 using Terminal Amine Isotopic Labeling of Substrates (TAILS).Design: Proteins from OA cartilage taken at knee arthroplasty (n = 6) or separately, from healthy cartilage incubated in triplicate with/without active HtrA1, were labeled at natural and proteolytically cleaved N-termini by reductive dimethylation, followed by trypsin digestion, enrichment of N-terminally labeled/blocked peptides, tandem mass spectrometry and positional peptide annotation to identify cleavage sites. Biglycan proteolysis by HtrA1 was validated biochemically and Amino-Terminal Oriented Mass Spectrometry of Substrates (ATOMS) was used to define the HtrA1 cleavage sites.Results: We identified 10,155 unique internal peptides from 2,162 proteins, suggesting at least 10,797 cleavage sites in OA cartilage. 7,635 internal peptides originated in 371 extracellular matrix/secreted components, many undergoing extensive proteolysis. Rampant ragging of protein termini suggested pervasive exopeptidase activity. HtrA1, the most abundant protease in OA cartilage, experimentally generated 323 cleavages in 109 cartilage proteins, accounting for 171 observed cleavages in the OA degradome. ATOMS identified HtrA1 cleavage sites in a selected substrate, biglycan, whose direct cleavage by HtrA1 was thus orthogonally validated.Conclusions: OA cartilage demonstrates widespread proteolysis by endo- and exopeptidases. HtrA1 contributes broadly to cartilage proteolysis. Forward degradomics of OA cartilage together with reverse degradomics of proteases active in OA, e.g., HtrA1, can potentially fully annotate OA proteolytic pathways and provide new biomarkers. [ABSTRACT FROM AUTHOR]

Members of the widely conserved HtrA family of serine proteases are involved in multiple aspects of protein quality control. In this context, they have been shown to efficiently degrade misfolded proteins or protein fragments. However, recent reports suggest that folded proteins can also be native substrates. To gain a deeper understanding of how folded proteins are initially processed and subsequently degraded into short peptides by human HTRA1, we established an integrated and quantitative approach using time-resolved mass spectrometry, circular dichroism spectroscopy and bioinformatics. The resulting data provide high-resolution information on up to 178 individual proteolytic sites within folded ANXA1 (consisting of 346 amino acids), the relative frequency of cuts at each proteolytic site, the preferences of the protease for the amino acid sequence surrounding the scissile bond, as well as the degrees of sequential structural relaxation and unfolding of the substrate that occur during progressive degradation. Our workflow provides precise molecular insights into protease-substrate interactions, which could be readily adapted to address other post-translational modifications such as phosphorylation in dynamic protein complexes., Competing Interests: DECLARATION OF COMPETING INTERESTS The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Objective: Most lacunar strokes are sporadic, and hypertension, diabetes, smoking, and cardiovascular diseases are among its main risk factors. Strokes caused by small vessel diseases are generally associated with single-gene disorders with familial dominant and recessive inheritance. The most common condition is cerebral autosomal dominant arteriopathy, with subcortical infarcts and leukoencephalopathy (CADASIL), associated with the NOTCH3 gene. An infrequent form of this disease is the cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL), revealed with pathogenic HTRA1 gene variants related to distinct molecular pathways. The neurological and cranial magnetic resonance imaging (MRI) findings are very similar to CADASIL; however, earlier than expected onset of common alopecia in man, low back pain, and more severe memory impairment are the differences in terms of clinical presentations. Clinical findings of 22 patients from 16 families with widespread white matter lesions in the periventricular field in the brain were investigated with molecular genetic findings. Materials and Methods: Clinical examination results and cranial MRI findings are reported, and NOTCH3 and HTRA1 genes are sequenced stepwise by Sanger and next-generation sequencing techniques. Results: Missense changes in epidermal growth factor (EGF)-like domain in the NOTCH3 are found in 18 cases from 14 families. Two different homozygous pathogenic missense and non-sense variants, in the HTRA1 gene, were detected in four patients from two families. The disease onset age was approximately 16 years earlier in cases carrying pathogenic variants located in the encoding region of EGF-like domains 1-6 of NOTCH3. Conclusion: In the NOTCH3 gene with c.382T>C (p.C128R), c.555T>G (p.C185W), and c.1903C>T (p.R635C) and in the HTRA1 gene c.235C>T (p.Q79*) are presented for the first time in this study. Molecular genetic investigation of CADASIL and CARASIL is important to support the clinical diagnosis, determine the inheritance model, provide patient and family counseling, manage disease process, and evaluate possible treatment strategies.

Abstract Background Biallelic HTRA1 pathogenic variants are associated with autosomal recessive cerebral arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL). Recent studies have indicated that heterozygous HTRA1 variants are related to autosomal dominant hereditary cerebral small vessel disease (CSVD). However, few studies have assessed heterozygous HTRA1 carriers or the genotype–phenotype correlation. Methods The clinical data of two unrelated Chinese Han families with CSVD were collected. Panel sequencing was used to search for pathogenic genes, Sanger sequencing was used for verification, three‐dimensional protein models were constructed, and pathogenicity was analyzed. Published HTRA1‐related phenotypes included in PubMed up to September 2021 were extensively reviewed, and the patients' genetic and clinical characteristics were summarized. Results We report a novel heterozygous variant c.920T>C p.L307P in the HTRA1, whose main clinical and neuroimaging phenotypes are stroke and gait disturbance. We report another patient with the previously reported pathogenic variant HTRA1 c.589C>T p.R197X characterized by early cognitive decline. A literature review indicated that compared with CARASIL, HTRA1‐related autosomal dominant hereditary CSVD has a later onset age, milder clinical symptoms, fewer extraneurological symptoms, and slower progression, indicating a milder CARASIL phenotype. In addition, HTRA1 heterozygous variants were related to a higher proportion of vascular risk factors (p

Age-related maculopathy susceptibility 2 (ARMS2) is considered the most enigmatic of the genes for age-related macular degeneration (AMD). We investigated the phenotypic course and spectrum of AMD for the risk haplotype at the ARMS2 and high-temperature requirement A serine peptidase 1 (HTRA1) locus in a large European consortium. Pooled analysis of 4 case-control and 6 cohort studies. Individuals (N = 17 204) aged 55 years or older participating in the European Eye Epidemiology consortium. Age-related macular degeneration features and macular thickness were determined on multimodal images; data on genetics and phenotype were harmonized. Risks of AMD features for rs3750486 genotypes at the ARMS2 / HTRA1 locus were determined by logistic regression and were compared with a genetic risk score (GRS) of 19 variants at the complement pathway. Lifetime risks were estimated with Kaplan–Meier analyses in population-based cohorts. Age-related macular degeneration features and stage. Of 2068 individuals with late AMD, 64.7% carried the ARMS2/HTRA1 risk allele. For homozygous carriers, the odds ratio (OR) of geographic atrophy was 8.6 (95% confidence interval [CI], 6.5–11.4), of choroidal neovascularization (CNV) was 11.2 (95% CI, 9.4–13.3), and of mixed late AMD was 12.2 (95% CI, 7.3–20.6). Cumulative lifetime risk of late AMD ranged from 4.4% for carriers of the nonrisk genotype to 9.4% and 26.8% for heterozygous and homozygous carriers. The latter received the diagnosis of late AMD 9.6 years (95% CI, 8.0–11.2) earlier than carriers of the nonrisk genotype. The risk haplotype was not associated with hard or soft drusen < 125 μm (OR, 1.2; 95% CI, 0.9–1.7), but risks increased significantly for soft drusen ≥ 125 μm (OR, 2.1; 95% CI, 1.5–3.0), up to an OR of 7.2 (95% CI, 3.8–13.8) for reticular pseudodrusen. Compared with persons with a high GRS for complement, homozygous carriers of ARMS2 / HTRA1 showed a higher risk of CNV (OR, 4.1; 95% CI, 3.2–5.4); risks of other characteristics were not different. Carriers of the risk haplotype at ARMS2/HTRA1 have a particularly high risk of late AMD at a relatively early age. Data suggest that risk variants at ARMS2/HTRA1 act as a strong catalyst of progression once early signs are present. The phenotypic spectrum resembles that of complement genes, only with higher risks of CNV. [ABSTRACT FROM AUTHOR]

Age-related macular degeneration (AMD) is among the leading causes of irreversible blindness worldwide. In addition to environmental risk factors, such as tobacco use and diet, genetic background has long been established as a major risk factor for the development of AMD. However, our ability to predict disease risk and personalize treatment remains limited by our nascent understanding of the molecular mechanisms underlying AMD pathogenesis. Research into the molecular genetics of AMD over the past two decades has uncovered 52 independent gene variants and 34 independent loci that are implicated in the development of AMD, accounting for over half of the genetic risk. This research has helped delineate at least five major pathways that may be disrupted in the pathogenesis of AMD: the complement system, extracellular matrix remodeling, lipid metabolism, angiogenesis, and oxidative stress response. This review surveys our current understanding of each of these disease mechanisms, in turn, along with their associated pathogenic gene variants. Continued research into the molecular genetics of AMD holds great promise for the development of precision-targeted, personalized therapies that bring us closer to a cure for this debilitating disease. [ABSTRACT FROM AUTHOR]

Inflammation and elevated expression of high temperature requirement A serine peptidase 1 (HTRA1) are known high risk factors for age-related macular degeneration (AMD). However, the specific mechanism that HTRA1 causes AMD and the relationship between HTRA1 and inflammation remains unclear. We found that lipopolysaccharide (LPS) induced inflammation enhanced the expression of HTRA1, NF-κB, and p-p65 in ARPE-19 cells. Overexpression of HTRA1 up-regulated NF-κB expression, and on the other hand knockdown of HTRA1 down-regulated the expression of NF-κB. Moreover, NF-κB siRNA has no significant effect on the expression of HTRA1, suggesting HTRA1 works upstream of NF-κB. These results demonstrated that HTRA1 plays a pivotal role in inflammation, explaining possible mechanism of overexpressed HTRA1-induced AMD. Celastrol, a very common anti-inflammatory and antioxidant drug, was found to suppress inflammation by inhibiting phosphorylation of p65 protein efficaciously in RPE cells, which may be applied to the therapy of age-related macular degeneration.

Zymogen activation is a widely conserved regulatory principle across protease clans. It describes the irreversible activation by processing of the inactive zymogen precursor by an active protease. Here we report an alternative and reversible mechanism of protease activation, where the activator is an inactive protease. This mechanism involves the formation of an allosteric complex between the serine PDZ protease HTRA1 and the cysteine protease calpain 2. Surprisingly, the allosteric activation of HTRA1 is restricted to a subset of substrate conformations as it improves the proteolysis of soluble tau protein but not the dissociation and degradation of amyloid fibrils that are a prominent hallmark of Alzheimer's disease. These data exemplify an additional challenge for protein quality control factors such as HTRA1 in the clearing of pathogenic fibrils and suggest a potential for unexpected side effects of chemical modulators targeting allosteric sites. [ABSTRACT FROM AUTHOR]

Objective: Melatonin has an inhibitory effect on preeclampsia (PE). This study was launched to explore the way that melatonin regulated trophoblast migration, invasion, and pyroptosis in PE and to provide new ideas for the diagnosis and treatment of PE. Methods: Expression levels of melatonin receptors (MT1 and MT2), microRNA (miR)‐520c‐3p, SETD7, and HtrA1 in placental tissues and HTR8/SVneo cells were measured by RT‐qPCR and Western blot. Scratch, Transwell, and Western blot assays were performed to detect migration, invasion, and pyroptosis of hypoxia/reoxygenation (H/R)‐treated HTR8/SVneo cells. Dual‐luciferase reporter assay was utilized to verify the targeting relationship between miR‐520c‐3p and SETD7. ChIP experiment was conducted to detect the enrichment of H3K4me3 and SETD7 in HtrA1 promoter. Results: Low expression of MT1, MT2, and miR‐520c‐3p and high expression of SETD7 and HtrA1 were observed in the placental tissues of PE patients and H/R‐treated HTR8/Svneo cells. A high concentration of melatonin promoted migration and invasion and inhibited pyroptosis of PE cell models. Knockdown of miR‐520c‐3p, overexpression of SETD7, or overexpression of HtrA1 impaired migration and invasion and accelerated pyroptosis of H/R‐treated HTR8/SVneo cells, but these outcomes could be reversed by treatment with 1000 μM melatonin. miR‐520c‐3p targeted SETD7 which promoted histone methylation in the promoter region of HtrA1. Conclusion: Melatonin may inhibit HtrA1 transcription through the miR‐520c‐3p/SETD7 axis to promote trophoblast invasion and migration and reduce trophoblast pyroptosis in PE. [ABSTRACT FROM AUTHOR]

The high temperature requirement factor A1 (HTRA1) is a serine protease which modulates an array of signalling pathways driving basal biological processes. HTRA1 plays a significant role in cell proliferation, migration and fate determination, in addition to controlling protein aggregates through refolding, translocation or degradation. The mutation of HTRA1 has been implicated in a plethora of disorders and this has also led to its growing interest as drug therapy target. This review details the involvement of HTRA1 in certain signalling pathways, namely the transforming growth factor beta (TGF-β), canonical Wingless/Integrated (WNT) and NOTCH signalling pathways during organogenesis and various disease pathogenesis such as preeclampsia, age-related macular degeneration (AMD), small vessel disease and cancer. We have also explored possible avenues of exploiting the serine proteases for therapeutic management of these disorders. [ABSTRACT FROM AUTHOR]

Introduction: The aim of this study was to investigate the association of the HtrA1 rs11200638 polymorphism with neovascular age-related macular degeneration (nAMD) in Indonesia. Methods: This case–control study included 80 patients with nAMD and 85 controls. Demographic parameters and whole blood were collected from each participant. Genomic DNA was extracted and used to assess the rs11200638 genotype by PCR and restriction enzyme digestion. Associations between the HtrA1 rs11200638 polymorphism and other risk factors for susceptibility to nAMD were assessed using the logistic regression model. Results: Significant allelic associations between the HtrA1 polymorphism and nAMD were detected (odds ratio [OR] 8.67; 95% confidence interval [CI] 4.88–15.41; P < 0.001). Genotype analysis showed a statistical difference between the nAMD group and the control group (P < 0.001). In the multiple adjusted logistic regression model, people with the AA genotype were more likely to have nAMD although there was a wide confidence interval (OR 19.65; 95% CI 4.52–85.38; P < 0.001). Conclusion: Our findings show that the risk of nAMD increased in the presence of risk alleles of HtrA1 rs11200638. [ABSTRACT FROM AUTHOR]

Cerebral amyloid angiopathy (CAA) is an age-related condition and a major cause of intracerebral hemorrhage and cognitive decline that shows close links with Alzheimer's disease (AD). CAA is characterized by the aggregation of amyloid-β (Aβ) peptides and formation of Aβ deposits in the brain vasculature resulting in a disruption of the angioarchitecture. Capillaries are a critical site of Aβ pathology in CAA type 1 and become dysfunctional during disease progression. Here, applying an advanced protocol for the isolation of parenchymal microvessels from post-mortem brain tissue combined with liquid chromatography tandem mass spectrometry (LC–MS/MS), we determined the proteomes of CAA type 1 cases (n = 12) including a patient with hereditary cerebral hemorrhage with amyloidosis-Dutch type (HCHWA-D), and of AD cases without microvascular amyloid pathology (n = 13) in comparison to neurologically healthy controls (n = 12). ELISA measurements revealed microvascular Aβ1-40 levels to be exclusively enriched in CAA samples (mean: > 3000-fold compared to controls). The proteomic profile of CAA type 1 was characterized by massive enrichment of multiple predominantly secreted proteins and showed significant overlap with the recently reported brain microvascular proteome of patients with cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), a hereditary cerebral small vessel disease (SVD) characterized by the aggregation of the Notch3 extracellular domain. We found this overlap to be largely attributable to the accumulation of high-temperature requirement protein A1 (HTRA1), a serine protease with an established role in the brain vasculature, and several of its substrates. Notably, this signature was not present in AD cases. We further show that HTRA1 co-localizes with Aβ deposits in brain capillaries from CAA type 1 patients indicating a pathologic recruitment process. Together, these findings suggest a central role of HTRA1-dependent protein homeostasis in the CAA microvasculature and a molecular connection between multiple types of brain microvascular disease. [ABSTRACT FROM AUTHOR]

Background: Aberrant expression of circular RNAs (circRNAs) during placental development could affect fetal growth and contribute to preeclampsia (PE). Circ_0011460 was found to be differentially expressed in placental samples of PE. However, the exact function and mechanism of circ_0011460 in PE process remain largely undefined. Methods: Levels of circ_0011460, microRNA (miR)‐762, and high‐temperature requirement‐A serine peptidase 1 (HTRA1) were detected using quantitative real‐time polymerase chain reaction and Western blot. In vitro experiments in HTR8/SVneo cells were conducted using cell counting kit‐8, wound healing, transwell, flow cytometry and Western blot assays. The direct interactions between miR‐762 and circ_0011460 or HTRA1 were verified using dual‐luciferase reporter, RNA immunoprecipitation (RIP) and RNA pull‐down assays. Results: Circ_0011460 possessed a loop structure and was highly expressed in placental tissues of PE patients. Overexpression of circ_0011460 greatly suppressed HTR8/SVneo cell proliferation, migration, and invasion, and accelerated cell apoptosis. While circ_0011460 knockdown yielded the opposite trends on above biological behaviors. Mechanistically, we confirmed that circ_0011460 could up‐regulate HTRA1 expression via serving as a sponge of miR‐762. Further rescue studies demonstrated that circ_0011460 exerted its roles via targeting miR‐762, and miR‐762 promoted HTR8/SVneo cell growth, migration and invasion via regulating HTRA1. Conclusion: In all, circ_0011460 suppressed HTR8/SVneo cell growth, migration, and invasion via miR‐762/HTRA1 axis, suggesting a new insight into the pathogenesis of PE. [ABSTRACT FROM AUTHOR]