High Temperature Requirement A1 Research Articles

Circ_0007445 inhibits trophoblast cell proliferation, migration and invasion by mediating the miR-4432/HTRA1 axis in preeclampsia.

: Circular RNAs (circRNAs) have been shown to be extensively involved in preeclampsia progression. At present, the role of circ_0007445 in preeclampsia progression is not clear. A total of 30 preeclampsia patients and 30 normal pregnant women were recruited in our study. The function of trophoblast cells was explored to clarify the role and mechanism of circ_0007445 on the preeclampsia progression. The expression of circ_0007445, microRNA (miR)-4432 and high temperature requirement A1 (HTRA1) was analyzed by quantitative real-time PCR. The proliferation, migration and invasion of trophoblast cells were determined by cell counting kit 8 assay, EdU assay, colony formation assay, flow cytometry, and transwell assay. Protein expression was examined by western blot analysis. Dual-luciferase reporter assay, RNA immunoprecipitation (RIP) assay and RNA pull-down assay were used to assess RNA interaction relationships. Our data suggested that circ_0007445 had increased expression in preeclampsia patients. Knockdown of circ_0007445 enhanced trophoblast cell proliferation, migration and invasion. MiR-4432 was lowly expressed in preeclampsia patients, and it could be sponged by circ_0007445. MiR-4432 inhibitor overturned the promotion effects of circ_0007445 knockdown on trophoblast cell functions. HTRA1 was highly expressed in preeclampsia patients, and it could be targeted by miR-4432. HTRA1 overexpression could also reverse the proliferation, migration and invasion of trophoblast cells promoted by miR-4432 mimic. In addition, circ_0007445 positively regulated HTRA1 through targeting miR-4432. :Our results suggested that circ_0007445 facilitated the development of preeclampsia by suppressing trophoblast cell function through miR-4432/HTRA1 axis.

Possible involvement of HtrA1 serine protease in the onset of osteoporotic bone extracellular matrix changes

High-temperature requirement A1 (HtrA1), a multidomain serine protease acting on Extracellular matrix (ECM) rearrangement, is also secreted by osteoblasts and osteoclasts. Recent and conflicting literature highlights HtrA1's role as a controller of bone remodeling, proposing it as a possible target for pathologies with unbalanced bone resorption, like Osteoporosis (OP). To add knowledge on this molecule function in bone physiopathology, here we compared HtrA1 distribution in the ECM of healthy (H) and OP bone tissue, also examining its localization in the sites of new bone formation. HtrA1 was homogeneously expressed in the mature bone ECM of H tissue showing a 55.6 ± 16.4% of the stained area, with a significant (p=0.0001) decrease in OP percentage stained area (21.1 ± 13.1). Moreover, HtrA1 was present in the endosteum and cells involved in osteogenesis, mainly in those “entrapped” in woven bone, whereas osteocytes in mature lamellar bone were negative. Based on our previous observation in OP tissue of a significantly increased expression of Decorin and Osteocalcin, both involved in bone mineralization and remodeling and equally substrates for HtrA1, we speculate that HtrA1 by controlling the proper amount of Decorin and Osteocalcin favors normal bone maturation and mineralization. Besides, we suggest that late-osteoblasts and pre-osteocytes secrete HtrA1 in the adjacent matrix whilst proceeding with their maturation and that HtrA1 expression is further modified during the remodeling from woven to the lamellar bone. Overall, our data suggest HtrA1 as a positive regulator of bone matrix formation and maturation: its reduced expression in mature OP bone, affecting protein content and distribution, could hamper correct bone remodeling and mineralization.

High temperature requirement A1 and macrophage migration inhibitory factor in the cerebrospinal fluid; a potential marker of conversion from relapsing-remitting to secondary progressive multiple sclerosis

BackgroundPredictive and prognostic biomarkers for multiple sclerosis (MS) remain a significant gap in MS diagnosis and treatment monitoring. Currently, there are no timely markers to diagnose the transition to secondary progressive MS (SPMS). ObjectiveThis study aims to evaluate the discriminatory potential of the High temperature requirement serine protease (HTRA1)/Macrophage migration inhibitory factor (MIF) cerebrospinal fluid (CSF) ratio in distinguishing relapsing-remitting (RRMS) patients from SPMS patients. MethodsThe MIF and HTRA1 CSF levels were determined using ELISA in healthy controls (n = 23), RRMS patients before (n = 22) and after 1 year of dimethyl fumarate treatment (n = 11), as well as in SPMS patients before (n = 11) and after 2 years of mitoxantrone treatment (n = 7). The ability of the HTRA1/MIF ratio to discriminate the different groups was determined using receiver operating curve (ROC) analyses. ResultsThe ratio was significantly increased in treatment naïve RRMS patients while decreased again in SPMS patients at baseline. Systemic administrated disease modifying treatment (DMT) only significantly affected the ratio in RRMS patients. ROC analysis demonstrated that the ratio could discriminate treatment naïve RRMS patients from SPMS patients with 91% sensitivity and 100% specificity. ConclusionThe HTRA1/MIF ratio is a strong candidate as a MS biomarker for SPMS conversion.

Progress in the Study of the Role and Mechanism of HTRA1 in Diseases Related to Vascular Abnormalities.

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.

HTRA1 expression is associated with immune-cell infiltration and survival in breast cancer.

High temperature requirement A1 (HTRA1), a member of the HTRA family, is a serine peptidase involved in many crucial bioprocesses such as proliferation, mitochondrial homeostasis, apoptosis, and protein quality control. It also plays an important role in the development of various tumors. However, the potential role and mechanisms of action of HTRA1 in breast cancer (BRCA) remain unclear. We conducted a bioinformatics-based study to investigate HTRA1 expression in BRCA alongside its associations with immune-cell infiltrates and survival outcomes. The expression of HTRA1 in BRCA samples was analyzed using RNAseq datasets from The Cancer Genome Atlas and Gene Expression Omnibus. R software was employed to assess the relationship between HTRA1 expression and clinicopathological characteristics, tumor-infiltrating immune cells, and immunity-associated biomarkers in BRCA. MethSurv and cBioPortal database were utilized to evaluate DNA methylation and genovariation within the HTRA1 DNA. Receiver operating characteristic curves, Kaplan-Meier analysis, and Cox regression were performed to estimate the impact of HTRA1 on diagnosis, prognosis, and response to chemotherapy in BRCA. HTRA1 expression was significantly downregulated in BRCA tissues compared to adjacent normal breast tissue controls. Differentially expressed genes associated with HTRA1 expression primarily enriched in cell proliferation pathways. Furthermore, altered HTRA1 expression significantly correlated with patient age, tumor histological type, T stage, progesterone receptor/estrogen receptor status, and PAM50 subtype of BRCA. Both positive and negative associations were observed between HTRA1 levels and the abundance of different types of immune cells, as well as immune biomarkers, including resting mast cells, follicular helper T cells, PD-L1, p53, and Ki67. Low HTRA1 expression was related with pathological complete response in luminal B BRCA patients undergoing chemotherapy. Additionally, lower HTRA1 expression in BRCA was associated with inferior overall survival and relapse-free survival. HTRA1 expression is associated with immune-cell infiltration, response to chemotherapy, and survival outcomes in BRCA. HTRA1 has the potential to serve as a promising biomarker and therapeutic target moving forward.

#6502 ETIOLOGICAL SPECTRUM OF MEMBRANOUS NEPHROPATHY

Abstract Background and Aims Primary MN includes forms of MN in which there is a humoral autoimmune response to a normal podocyte antigen in the absence of secondary features or etiologies of disease. Antigens implicated in primary MN include PLA2R, thrombospondin type-1 domain-containing 7A (THSD7A), neural epidermal growth factor-like 1 (NELL1), semaphorin 3B (Sema3B), the serine protease high-temperature requirement A1 (HTRA1), protocadherin 7 (PCDH7), and others. PLA2R associated MN is most common MN among primary MN. Nowadays, a significant number of newer antigens implicating MN are being discovered. Research is ongoing for a better understanding of the role of these antigens in pathophysiology, and targeted therapeutic implications in future if possible. We aim to analyze the etiological spectrum associated with different antigens in patients with Membranous Nephropathy. We assessed the renal tissue staining of autoantigens PLA2R, THSD7A, and NELL-1 in patients with biopsy-proven Membranous Nephropathy. Method This was a single center ambispective observational study. The study was performed up till September 2022 for prospective data, and retrospective data from January 2018 to March 2021 was retrieved from the medical records department of the institute. The study included patients with biopsy-proven Membranous Nephropathy (Primary and secondary). The primary outcome was to study the etiological spectrum of Membranous Nephropathy. Results A total of 90 patients were included in the study of membranous nephropathy over the period of 4 years. 72 cases had primary MN whereas 18 cases had secondary MN. The mean age was 42.01 ± 14.6 years. Among 18 cases of Secondary MN, the majority of the cases were of lupus nephritis 14 (78%), while other etiologies of secondary MN were malignancy related (11%), rheumatoid arthritis (5.5%) and HCV (5.5%). PLA2R renal tissue positivity was found in 44 (61.1%) cases of primary MN, whereas in 4 (22.2%) cases of Secondary MN. The THSD7A was found in 4 (5.6%) cases of primary MN. One patient of MN was dual PLA2R and NELL1 positive. Two cases of MN were dual PLA2R and THSD7A positive. Renal tissue staining for NELL-1 was found in 8 (11.1%) cases of primary MN whereas it was found in 1 (5.6%) case of secondary MN. In terms of clinical presentation, proteinuria is the most common clinical finding present in nearly all the patients (80%). Most of the cases with nephrotic syndrome (60%) belonged to primary MN. Conclusion PLA2R is the most common etiology of Primary membranous nephropathy. None of the antigens was exclusive to primary membranous nephropathy.

Nupr1 deficiency downregulates HtrA1, enhances SMAD1 signaling, and suppresses age-related bone loss in male mice.

Nuclear protein 1 (NUPR1) is a stress-induced protein activated by various stresses, such as inflammation and oxidative stress. We previously reported that Nupr1 deficiency increased bone volume by enhancing bone formation in 11-week-old mice. Analysis of differentially expressed genes between wild-type (WT) and Nupr1-knockout (Nupr1-KO) osteocytes revealed that high temperature requirement A 1 (HTRA1), a serine protease implicated in osteogenesis and transforming growth factor-βsignaling was markedly downregulated in Nupr1-KO osteocytes. Nupr1 deficiency also markedly reduced HtrA1 expression, but enhanced SMAD1 signaling in in vitro-cultured primary osteoblasts. In contrast, Nupr1 overexpression enhanced HtrA1 expression in osteoblasts, suggesting that Nupr1 regulates HtrA1 expression, thereby suppressing osteoblastogenesis. Since HtrA1 is also involved in cellular senescence and age-related diseases, we analyzed aging-related bone loss in Nupr1-KO mice. Significant spine trabecular bone loss was noted in WT male and female mice during 6-19 months of age, whereas aging-related trabecular bone loss was attenuated, especially in Nupr1-KO male mice. Moreover, cellular senescence-related markers were upregulated in the osteocytes of 6-19-month-old WT male mice but markedly downregulated in the osteocytes of 19-month-old Nupr1-KO male mice. Oxidative stress-induced cellular senescence stimulated Nupr1 and HtrA1 expression in in vitro-cultured primary osteoblasts, and Nupr1 overexpression enhanced p16ink4a expression in osteoblasts. Finally, NUPR1 expression in osteocytes isolated from the bones of patients with osteoarthritis was correlated with age. Collectively, these results indicate that Nupr1 regulates HtrA1-mediated osteoblast differentiation and senescence. Our findings unveil a novel Nupr1/HtrA1 axis, which may play pivotal roles in bone formation and age-related bone loss.

Endoplasmic reticulum stress-regulated high temperature requirement A1 (HTRA1) modulates invasion and angiogenesis-related genes in human trophoblasts

The pathogenesis of hypertensive disorder of pregnancy (HDP), which affects about 10% of pregnant women, is still incompletely understood. Our previous study showed that endoplasmic reticulum (ER) stress influences high-temperature requirement A serine peptidase 1 (HTRA1) expression and trophoblast invasion. However, the involvement of ER stress in the regulation of HTRA subtype expression and pathophysiology of HDP has not been characterized in extravillous trophoblasts (EVTs). To investigate this, HTR8/SVneo EVTs cell line was treated with the ER stress inducers Thapsigargin (Thap) or Tunicamycin (Tuni). Treatment with either Thap or Tuni inhibited trophoblast invasion, reduced HTRA1 and HTRA3 expression, but did not alter HTRA2 or HTRA4 expression. Knockdown of HTRA1 or HTRA3 also inhibited trophoblast invasion. Furthermore, treatment with either ER stress inducer or HTRA1 silencing increased the ratio of soluble fms-like tyrosine kinase-1/placental growth factor (sFLT1/PlGF), which is a marker of HDP. Immunohistochemical analysis revealed that HTRA1 is localized to EVTs and the endometrial decidua in the placenta of patients with HDP. These results suggest that factors that cause ER stress could result in the inhibition of EVTs invasion via HTRA1.

HTRA1 Regulates Subclinical Inflammation and Activates Proangiogenic Response in the Retina and Choroid.

High-temperature requirement A1 (HtrA1) has been identified as a disease-susceptibility gene for age-related macular degeneration (AMD) including polypoidal choroidal neovasculopathy (PCV). We characterized the underlying phenotypic changes of transgenic (Tg) mice expressing ubiquitous CAG promoter (CAG-HtrA1 Tg). In vivo imaging modalities and histopathology were performed to investigate the possible neovascularization, drusen formation, and infiltration of macrophages. Subretinal white material deposition and scattered white-yellowish retinal foci were detected on CFP [(Tg—33% (20/60) and wild-type (WT)—7% (1/15), p < 0.05]. In 40% (4/10) of the CAG-HtrA1 Tg retina, ICGA showed punctate hyperfluorescent spots. There was no leakage on FFA and OCTA failed to confirm vascular flow signals from the subretinal materials. Increased macrophages and RPE cell migrations were noted from histopathological sections. Monocyte subpopulations were increased in peripheral blood in the CAG-HtrA1 Tg mice (p < 0.05). Laser induced CNV in the CAG-HtrA1 Tg mice and showed increased leakage from CNV compared to WT mice (p < 0.05). Finally, choroidal explants of the old CAG-HtrA1 Tg mice demonstrated an increased area of sprouting (p < 0.05). Signs of subclinical inflammation was observed in CAG-HtrA1 Tg mice. Such subclinical inflammation may have resulted in increased RPE cell activation and angiogenic potential.

The multifaced role of HtrA1 in the development of joint and skeletal disorders.

HtrA1 (High temperature requirement A1) family proteins include four members, widely conserved from prokaryotes to eukaryotes, named HtrA1, HtrA2, HtrA3 and HtrA4. HtrA1 is a serine protease involved in a variety of biological functions regulating many signaling pathways degrading specific components and playing key roles in many human diseases such as neurodegenerative disorders, pregnancy complications and cancer. Due to its role in the breakdown of many ExtraCellular Matrix (ECM) components of articular cartilage such as fibronectin, decorin and aggrecan, HtrA1 encouraged many researches on studying its role in several skeletal diseases (SDs). These studies were further inspired by the fact that HtrA1 is able to regulate the signaling of one of the most important cytokines involved in SDs, the TGFβ-1. This review aims to summarize the data currently available on the role of HtrA1 in skeletal diseases such as Osteoporosis, Rheumatoid Arthritis, Osteoarthritis and Intervertebral Disc Degeneration (IDD). The use of HtrA1 as a marker of frailty in geriatric medicine would represent a powerful tool for identifying older individuals at risk of developing skeletal disorders, evaluating an appropriate intervention to improve quality care in these people avoiding or improving age-related SDs in the elderly population.

Role of ER stress-regulated high-temperature requirement A1 (HTRA1) in the function of placental cells in hypertensive disorder of pregnancy

Role of ER stress-regulated high-temperature requirement A1 (HTRA1) in the function of placental cells in hypertensive disorder of pregnancy

Candesartan prevents arteriopathy progression in cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy model.

Cerebral small vessel disease (CSVD) causes dementia and gait disturbance due to arteriopathy. Cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL) is a hereditary form of CSVD caused by loss of high-temperature requirement A1 (HTRA1) serine protease activity. In CARASIL, arteriopathy causes intimal thickening, smooth muscle cell (SMC) degeneration, elastic lamina splitting, and vasodilation. The molecular mechanisms were proposed to involve the accumulation of matrisome proteins as substrates or abnormalities in transforming growth factor β (TGF-β) signaling. Here, we show that HTRA1-/- mice exhibited features of CARASIL-associated arteriopathy: intimal thickening, abnormal elastic lamina, and vasodilation. In addition, the mice exhibited reduced distensibility of the cerebral arteries and blood flow in the cerebral cortex. In the thickened intima, matrisome proteins, including the hub protein fibronectin (FN) and latent TGF-β binding protein 4 (LTBP-4), which are substrates of HTRA1, accumulated. Candesartan treatment alleviated matrisome protein accumulation and normalized the vascular distensibility and cerebral blood flow. Furthermore, candesartan reduced the mRNA expression of Fn1, Ltbp-4, and Adamtsl2, which are involved in forming the extracellular matrix network. Our results indicate that these accumulated matrisome proteins may be potential therapeutic targets for arteriopathy in CARASIL.

Binding of Gtf2i-β/δ transcription factors to the ARMS2 gene leads to increased circulating HTRA1 in AMD patients and in vitro

The disease-initiating molecular events for age-related macular degeneration (AMD), a multifactorial retinal disease affecting many millions of elderly individuals worldwide, are still unknown. Of the over 30 risk and protective loci so far associated with AMD through whole genome-wide association studies (GWAS), the Age-Related Maculopathy Susceptibility 2 (ARMS2) gene locus represents one of the most highly associated risk regions for AMD. A unique insertion/deletion (in/del) sequence located immediately upstream of the High Temperature Requirement A1 (HTRA1) gene in this region confers high risk for AMD. Using electrophoretic mobility shift assay (EMSA), we identified that two Gtf2i-β/δ transcription factor isoforms bind to the cis-element 5′- ATTAATAACC-3′ contained in this in/del sequence. The binding of these transcription factors leads to enhanced upregulation of transcription of the secretory serine protease HTRA1 in transfected cells and AMD patient-derived induced pluripotent stem cells (iPSCs). Overexpression of Htra1 in mice using a CAG-promoter demonstrated increased blood concentration of Htra1 protein, caused upregulation of vascular endothelial growth factor (VEGF), and produced a choroidal neovascularization (CNV)-like phenotype. Finally, a comparison of 478 AMD patients to 481 healthy, age-matched controls from Japan, India, Australia, and the USA showed a statistically increased level of secreted HTRA1 blood concentration in AMD patients compared with age-matched controls. Taken together, these results suggest a common mechanism across ethnicities whereby increased systemic blood circulation of secreted serine protease HTRA1 leads to subsequent degradation of Bruch's membrane and eventual CNV in AMD.

Fetal growth restriction is a host specific response to infection with an impaired spiral artery remodeling-inducing strain of Porphyromonas gingivalis

Porphyromonas gingivalis is a periodontal pathogen implicated in a range of pregnancy disorders that involve impaired spiral artery remodeling (ISAR) with or without fetal growth restriction (FGR). Using a rodent periodontitis model, we assessed the ability of P. gingivalis to produce ISAR and FGR in Sprague Dawley (SD) and Wistar (WIS) rats. Both infected SD and WIS rats developed ISAR, but only WIS rats developed FGR despite both rat strains having equivalent microbial loads within the placenta. Neither maternal systemic inflammation nor placental (fetal) inflammation was a feature of FGR in WIS rats. Unique to infected WIS rats, was loss of trophoblast cell density within the junctional zone of the placenta that was not present in SD tissues. In addition, infected WIS rats had a higher proportion of junctional zone trophoblast cells positive for cytoplasmic high temperature requirement A1 (Htra1), a marker of cellular oxidative stress. Our results show a novel phenomenon present in P. gingivalis-induced FGR, with relevance to human disease since dysregulation of placental Htra1 and placental oxidative stress are features of preeclamptic placentas and preeclampsia with FGR.

A Molecular Cascade Underlying Articular Cartilage Degeneration.

Preserving of articular cartilage is an effective way to protect synovial joints from becoming osteoarthritic (OA) joints. Understanding of the molecular basis of articular cartilage degeneration will provide valuable information in the effort to develop cartilage preserving drugs. There are currently no disease-modifying OA drugs (DMOADs) available to prevent articular cartilage destruction during the development of OA. Current drug treatments for OA focus on the reduction of joint pain, swelling, and inflammation at advanced stages of the disease. However, based on discoveries from several independent research laboratories and our laboratory in the past 15 to 20 years, we believe that we have a functional molecular understanding of articular cartilage degeneration. In this review article, we present and discuss experimental evidence to demonstrate a sequential chain of the molecular events underlying articular cartilage degeneration, which consists of transforming growth factor beta 1, high-temperature requirement A1 (a serine protease), discoidin domain receptor 2 (a cell surface receptor tyrosine kinase for native fibrillar collagens), and matrix metalloproteinase 13 (an extracellularmatrix degrading enzyme). If, as we strongly suspect, this molecular pathway is responsible for the initiation and acceleration of articular cartilage degeneration, which eventually leads to progressive joint failure, then these molecules may be ideal therapeutic targets for the development of DMOADs.

First trimester HtrA1 maternal plasma level and spontaneous preterm birth

Objectives High temperature requirement A1 (HtrA1) is a serine protease detected in maternal plasma and in placental tissues during normal gestation and in various pathological conditions. The purpose of this study was to determine whether the maternal plasma concentration of HtrA1 in first trimester, alone or combined with other maternal factors, can be used to identify women at risk for spontaneous preterm birth (SPTB). Study design This is a cohort study on pregnant women at 12 weeks of gestation recruited between 2014 and 2016 and prospectively followed until delivery. One hundred and fifty-nine women were included in the study: 140 women delivered at term and 19 (11.9%) delivered spontaneously preterm. Plasma samples were assessed for HtrA1 by ELISA and data were compared between women which delivered at term with women which delivered preterm. A multiple logistic regression analysis was used to estimate the independent effect of women’s characteristics on the probability of a SPTB. Results SPTB was significantly associated with log HtrA1 values at 12 weeks of gestation, BMI before pregnancy and physical activity. In particular, the probability of a SPTB increases of 79% for every added unit of log HtrA1, while decreases of 18% for every added unit of BMI. In addition, physical activity was found as an important protective factor. The ROC curve showed that the model had a good accuracy in predicting SPTB, with an AUC equal to 0.83 (95%CI: 0.73–0.91). Conclusions Maternal plasma HtrA1 may be considered a marker of SPTB. In addition, our model indicates two factors that could be modified to reduce the risk of SPTB, i.e. BMI before pregnancy and maternal physical activity.

HTRA1 expression profile and activity on TGF-β signaling in HTRA1 mutation carriers.

High temperature requirement A1 (HTRA1) is a serine protease playing a modulatory role in various cell processes, particularly in the regulation of transforming growth factor-β (TGF-β) signaling. A deleterious role in late-onset cerebral small vessel diseases (CSVDs) of heterozygous HTRA1 mutations, otherwise causative in homozygosity of cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy, was recently suggested. However, the pathomechanism of these heterozygous mutations is still undefined. Our aim is to evaluate the expression profile and activity of HTRA1 on TGF-β signaling in fibroblasts from four subjects carrying the HTRA1 heterozygous mutations-p.E42Dfs*173, p.A321T, p.G295R, and p.Q151K. We found a 50% reduction of HTRA1 expression in HTRA1 mutation carriers compared to the control. Moreover, we showed no changes in TGF-β signaling pathway downstream intermediate, Phospho Smad2/3. However, we found overexpression of genes involved in the extracellular matrix formation in two heterozygous HTRA1 carriers. Our results suggest that each heterozygous HTRA1 missense mutation displays a different and peculiar HTRA1 expression pattern and that CSVD phenotype may also result from 50% of HTRA1 expression.

An association of neovascular age-related macular degeneration with polymorphisms of CFH, ARMS2, HTRA1 and C3 genes in Czech population.

We investigated associations between neovascular age-related macular degeneration (AMD) and rs10490924 polymorphism of ARMS2 gene (age-related maculopathy susceptibility 2), rs1061170 polymorphism of gene for complement factor H (CFH), rs2230199 polymorphism of gene for complement component C3 and rs11200638 polymorphism of gene for serine protease high-temperature requirement A1 (HTRA1) in the Czech population. We analysed samples of DNA from 307 patients diagnosed with neovascular form of late AMD (average age: 73.7±7.7years) and 191 control subjects, recruited from patients awaiting cataract surgery (average age, 73.6±8.7years). HTRA1, CFH and ARMS2 genes polymorphisms were found to be related to neovascular AMD in the Czech population. All analysed polymorphisms were statistically significantly associated with neovascular AMD, with stronger associations in females than in males. In whole group, CC genotype of CFH gene polymorphism, TT genotype of ARMS2 gene polymorphism and AA genotype of HTRA1 gene polymorphism showed the greatest risk for neovascular AMD with odds ratios equal to 8.43, 10.07, 9.83, respectively (p<0.0001). Only CG polymorphism ofC3 gene showed statistically significant risk for neovascular AMD. In addition, we observed an association between waist circumference and neovascular AMD in both sexes, which further suggests the significance of excessive abdominal fat as a risk factor of AMD. We found a statistically significant association between polymorphisms in HTRA1, CFH and ARMS2 genes and neovascular AMS in the Czech population. The association was stronger in females than in males. We demonstrated a relationship between neovascular AMD and genes for HTRA1, CFH, ARMS2 and C3 in Czech population. To our knowledge, the relationship between these polymorphisms and neovascular AMD in Czech population has never been investigated before.

Antithrombin is incorporated into exosomes produced by antithrombin non-expressing cells

Antithrombin is a serine protease inhibitor that exerts a crucial role in hemostasis as the main inhibitor of the coagulation cascade. It plays also critical roles in other processes, such as inflammation and cancer. Here we show that exosomes released by Madin-Darby canine kidney (MDCK) cells cultured in the presence of heparin incorporate antithrombin from the serum. Exosomal antithrombin is found complexed with the serine protease high temperature requirement A1 (HTRA1), whose cellular levels are increased after serum deprival, the condition used to collect exosomes. Although the biological relevance of the presence of antithrombin in exosomes remains to be investigated, our results suggest a functional interplay between antithrombin and HTRA1.

High-Temperature Requirement A1 Protease as a Rate-Limiting Factor in the Development of Osteoarthritis

Preserving the mature articular cartilage of joints is a critical focus in the prevention and treatment of osteoarthritis. We determined whether the genetic inactivation of high-temperature requirement A1 (HtrA1) can significantly attenuate the degradation of articular or condylar cartilage. Two types of mouse models of osteoarthritis were used, a spontaneous mutant mouse model [type XI collagen-haploinsufficient (Col11a1+/-) mice] and two post-traumatic mouse models [destabilization of the medial meniscus (DMM) on the knee and a partial discectomy (PDE) on the temporomandibular joint]. Three different groups of mice were generated: i) HtrA1 was genetically deleted from Col11a1+/- mice (HtrA1-/-;Col11a1+/-), ii) HtrA1-deficient mice (HtrA1-/-) were subjected to DMM, and iii) HtrA1-/- mice were subjected to PDE. Knee and temporomandibular joints from the mice were characterized for evidence of cartilage degeneration. The degradation of articular or condylar cartilage was significantly delayed in HtrA1-/-;Col11a1+/- mice and HtrA1-/- mice after DMM or PDE. The amount of collagen type VI was significantly higher in the articular cartilage in HtrA1-/-;Col11a1+/- mice, compared with that in Col11a1+/- mice. The genetic removal of HtrA1 may delay the degradation of articular or condylar cartilage in mice.