HtrA3: a promising prognostic biomarker and therapeutic target for head and neck squamous cell carcinoma

Objective

The dysregulation of the human high-temperature requirement A (HtrA) family of serine proteases is associated with many malignancies. However, there are few reports on HtrAs in head and neck squamous cell carcinoma (HNSCC). The aim of this study was to investigate the expression, prognostic value, and biological functions of HtrAs in HNSCC.

Methods

The RNA-sequencing data and clinical data of HNSCC were downloaded from The Cancer Genome Atlas (TCGA) database. The GSE30784 and GSE31056 datasets from the Gene Expression Omnibus (GEO) database were used for further verification. This study explored the differential expression of HtrAs and assessed their potential impact on the prognosis of HNSCC patients using a survival module. Correlations between clinical characteristics and HtrA expression levels were then explored using a Wilcoxon rank sum test. A Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Gene Set Enrichment Analysis (GSEA) were performed using "clusterProfile" in the R software. A Pearson/Spearman correlation test was applied to analyze the relationship between HtrAs and immune infiltration level/checkpoint genes. Validation of HtrA expression levels were carried out by RT-PCR and western blot in human squamous carcinoma cell lines (Fadu and Cal-27) and human non-tumorigenic bronchial epithelium cells (BEAS-2B). Finally, through cell transfection, CCK-8, Ki-67 immunofluorescence, and flow cytometry assays, the effect of HtrA3 knockdown on the malignant biological behavior of HNSCC cells was explored.

Results

The gene expression levels of HtrAs were significantly upregulated and associated with patient age, TNM stage, clinical stage, and TP53 mutation status in the TCGA-HNSCC cohort. High expressions of HtrA1/3 were associated with shorter overall survival, shorter progress-free interval, and lower disease-specific survival in HNSCC. A nomogram for HtrAs was constructed and validated. HtrA-related genes were significantly enriched in the immune response and cell apoptosis pathway. In addition, the expression of HtrAs showed significant correlations with B cells, M cells, DC cell infiltration, and immune infiltration checkpoint (CD276, TNFRSF14). Validation of HtrA expression was carried out by RT-PCR and western blot. Results of in vitro experiments indicated that HtrA3 gene knockdown inhibits the proliferation of FaDu and Cal-27 cells while concurrently promoting apoptosis.

Conclusions

HtrA3 shows significant potential as both a prognostic marker and a promising therapeutic target for HNSCC, highlighting its relevance and importance in future research and potential clinical applications.

Identification of osteoarthritis-characteristic genes and immunological micro-environment features through bioinformatics and machine learning-based approaches

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.

The expanding spectrum and utility of antigens in membranous nephropathy

PURPOSE OF REVIEW

Multiple antigenic targets were discovered in membranous nephropathy, representing distinct autoimmune diseases with a similar morphologic pattern of injury. An overview of recent developments, including antigen types, clinical associations, serologic monitoring, and advancements in understanding disease pathogenesis are provided.

RECENT FINDINGS

Several new antigenic targets have defined subtypes of membranous nephropathy, including Neural epidermal growth factor-like 1, protocadherin 7, HTRA1, FAT1, SEMA3B, NTNG1, NCAM1, exostosin 1/2, transforming growth factor beta receptor 3, CNTN1, proprotein convertase subtilisin/kexin type 6, and neuron-derived neurotrophic factor. Autoantigens in membranous nephropathy may demonstrate unique clinical associations, assisting the nephrologist to identify potential disease etiologies and triggers, such as autoimmune disease, cancer, medications, and infections.

SUMMARY

We are entering an exciting era for which an antigen-based approach will further define subtypes of membranous nephropathy, allow for development of noninvasive diagnostics, and improve care for patients.

Association of Vascular Risk Factors and Genetic Factors With Penetrance of Variants Causing Monogenic Stroke

Importance

It is uncertain whether typical variants causing monogenic stroke are associated with cerebrovascular disease in the general population and why the phenotype of these variants varies so widely.

Objective

To determine the frequency of pathogenic variants in the 3 most common monogenic cerebral small vessel diseases (cSVD) and their associations with prevalent and incident stroke and dementia.

Design, Setting, and Participants

This cohort study is a multicenter population-based study of data from UK Biobank participants recruited in 2006 through 2010, with the latest follow-up in September 2021. A total of 9.2 million individuals aged 40 to 69 years who lived in the United Kingdom were invited to join UK Biobank, of whom 5.5% participated in the baseline assessment. Participants eligible for our study (n = 454 756, excluding 48 569 with incomplete data) had whole-exome sequencing and available data pertaining to lacunar stroke-related diseases, namely stroke, dementia, migraine, and epilepsy.

Exposures

NOTCH3, HTRA1, and COL4A1/2 pathogenic variants in monogenic stroke; Framingham cardiovascular risk; and ischemic stroke polygenic risk.

Main Outcomes and Measures

Primary outcomes were prevalent and incident stroke and dementia. Odds ratios (ORs) and hazard ratios (HRs) were adjusted for age, sex, ethnicity, exome sequencing batch, and top 10 genetic principal components.

Results

Of the 454 756 participants (208 027 [45.8%] men; mean [SD] age, 56.5 [8.1] years), 973 participants carried NOTCH3 variants, 546 carried HTRA1 variants, and 336 carried COL4A1/2 variants. Variant carriers were at least 66% more likely to have had stroke. NOTCH3 carriers had increased vascular dementia risk (OR, 5.42; 95% CI, 3.11-8.74), HTRA1 carriers an increased all-cause dementia risk (OR, 2.17; 95% CI, 1.28-3.41), and COL4A1/2 carriers an increased intracerebral hemorrhage risk (OR, 3.56; 95% CI, 1.34-7.53). NOTCH3 variants were associated with incident ischemic stroke and vascular dementia. NOTCH3 and HTRA1 variants were associated with magnetic resonance imaging markers of cSVD. Cardiovascular risk burden was associated with increased stroke risk in NOTCH3 and HTRA1 carriers. Variant location was also associated with risk.

Conclusions and Relevance

In this cohort study, pathogenic variants associated with rare monogenic stroke were more common than expected in the general population and associated with stroke and dementia. Cardiovascular risk burden is associated with the penetrance of such variants. Our results support the hypothesis that cardiovascular risk factor control may improve disease prognosis in individuals with monogenic cSVD variants. This lays the foundation for future studies to evaluate the effect of early identification before symptom onset on mitigating stroke and dementia risk.

Pediatric membranous nephropathy: In the novel antigens era

Membranous nephropathy (MN) falls within the scope of a glomerular disease. MN exhibits subepithelial immune- complex deposition and capillary wall thickening which could occur in all age groups. In comparison with adult patients with MN, MN in pediatric population has a lower incidence and more secondary factors (e.g., systemic lupus erythematosus, infection, malignancy, or drug toxicity). Two target antigens for the immune complexes, PLA2R (identified in 2009) and THSD7A (in 2014), found in previous studies and first presented in adult MN, are found in pediatric patients suffering from MN and their antibodies are now an effective tool for diagnosis and monitoring in children and adolescents. Several novel antigens have been identified (e.g., EXT1/EXT2, NELL1, Sema3B, PCDH7, HTRA1, and NCAM1) over the past few years. Each of them represents different clinical and pathologic findings. In-depth research should be conducted to gain insights into the outcomes and pathophysiology of the above novel antigen-associated MN. Targeted treatment opinions for different novel antigen-related MN are under development both in adults and pediatric patients.

[Clinical practice recommendations for hereditary cerebral small vessel disease in China]

Hereditary cerebral small vessel disease (hCVSD) is a group of rare cerebrovascular diseases caused by monogenic mutation. Although there is great variability in the age of onset of hCSVD patients, the age of onset younger than 45 years old is an important indicator. The primary clinical manifestations exhibit cognitive impairment, movement disorder, psychological disturbance, and most of which are accompanied by impairment of extra-neurological systems. The main radiological and pathological features of hCVSD include lacunar infarcts, white matter hyperdensities, cerebral microbleeds and enlargement of Virchow-Robin spaces. Current representative diseases include autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy, autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy, HTRA1 related autosomal dominant cerebellar small vessel disease, collagen 4A1/2 microangiopathy, retinal vasculopathy with cerebral leukoencephalopathy and systemic manifestations, hereditary cerebral amyloidosis angiopathy, and Fabry disease. In recent years, Chinese scholars have summarized diagnostic, and treatment processes in hCSVD patients. Therefore, we organize experts engaged in the studies of hCVSD, based on the Chinese reports and referring to the relevant foreign literatures, to put forward clinical working recommendations for clinical and imaging characteristics, as well as diagnosis and treatment workflows of different types of hCVSD. The aim of this recommendation is to guide physicians to recognize hCVSD patients from those of stroke in order to obtain timely diagnosis and standard treatment.

Pathophysiology of Age-Related Macular Degeneration: Implications for Treatment

Age-related macular degeneration (AMD) is a complex, multifactorial, progressive retinal disease that affects millions of people worldwide and has become the leading cause of visual impairment in developed countries. The disease etiopathogenesis is not understood fully, although many triggers and processes that lead to dysfunction and degeneration of the retinal pigment epithelium (RPE) have already been identified. Thus, the lack of cellular control of oxidative stress, altered proteostasis, dysfunction of lipid homeostasis, and mitochondrial dysfunction form an internal feedback loop that causes the RPE to fail and allows accumulation of abnormal misfolded proteins and abnormal lipids that will form drusen. An inadequate antioxidant response, deficits in autophagy mechanisms, and dysregulation of the extracellular matrix (ECM) help to increase the deposition of abnormal drusen material over time. The drusen then act as inflammatory centers that trigger chronic inflammation of the subretinal space in which microglia and recruited macrophages are also involved, and where the complement system is a key component. Choriocapillaris degeneration and nutritional influences are also classic elements recognized in the AMD pathophysiology. The genetic component of the disease is embodied in the recognition of the described risk or protective polymorphisms of some complement and ECM related genes (mainly CFH and ARMS2/HTRA1). Thus, carriers of the risk haplotype at ARMS2/HTRA1 have a higher risk of developing late AMD at a younger age. Finally, gut microbiota and epigenetics may play a role in modulating the progression to advanced AMD with the presence of local inflammatory conditions. Because of multiple implicated processes, different complex combinations of treatments will probably be the best option to obtain the best visual results; they in turn will differ depending on the type and spectrum of disease affecting individual patients or the disease stage in each patient at a specific moment. This will undoubtedly lead to personalized medicine for control and hopefully find a future cure. This necessitates the continued unraveling of all the processes involved in the pathogenesis of AMD that must be understood to devise the combinations of treatments for different concurrent or subsequent problems.

A Critical Overview of Targeted Therapies for Vestibular Schwannoma

Vestibular schwannoma (VS) is a benign tumor that originates from Schwann cells in the vestibular component. Surgical treatment for VS has gradually declined over the past few decades, especially for small tumors. Gamma knife radiosurgery has become an accepted treatment for VS, with a high rate of tumor control. For neurofibromatosis type 2 (NF2)-associated VS resistant to radiotherapy, vascular endothelial growth factor (VEGF)-A/VEGF receptor (VEGFR)-targeted therapy (e.g., bevacizumab) may become the first-line therapy. Recently, a clinical trial using a VEGFR1/2 peptide vaccine was also conducted in patients with progressive NF2-associated schwannomas, which was the first immunotherapeutic approach for NF2 patients. Targeted therapies for the gene product of SH3PXD2A-HTRA1 fusion may be effective for sporadic VS. Several protein kinase inhibitors could be supportive to prevent tumor progression because merlin inhibits signaling by tyrosine receptor kinases and the activation of downstream pathways, including the Ras/Raf/MEK/ERK and PI3K/Akt/mTORC1 pathways. Tumor-microenvironment-targeted therapy may be supportive for the mainstays of management. The tumor-associated macrophage is the major component of immunosuppressive cells in schwannomas. Here, we present a critical overview of targeted therapies for VS. Multimodal therapy is required to manage patients with refractory VS.

Hematopoietic Stem Cell Transplant-Membranous Nephropathy Is Associated with Protocadherin FAT1

BACKGROUND

Membranous nephropathy (MN) is a common cause of proteinuria in patients receiving a hematopoietic stem cell transplant (HSCT). The target antigen in HSCT-associated MN is unknown.

METHODS

We performed laser microdissection and tandem mass spectrometry (MS/MS) of glomeruli from 250 patients with PLA2R-negative MN to detect novel antigens in MN. This was followed by immunohistochemical (IHC)/immunofluorescence (IF) microscopy studies to localize the novel antigen. Western blot analyses using serum and IgG eluted from frozen biopsy specimen to detect binding of IgG to new 'antigen'.

RESULTS

MS/MS detected a novel protein, protocadherin FAT1 (FAT1), in nine patients with PLA2R-negative MN. In all nine patients, MN developed after allogeneic HSCT (Mayo Clinic discovery cohort). Next, we performed MS/MS in five patients known to have allogeneic HSCT-associated MN (Cedar Sinai validation cohort). FAT1 was detected in all five patients by MS/MS. The total spectral counts for FAT1 ranged from 8 to 39 (mean±SD, 20.9±10.1). All 14 patients were negative for known antigens of MN, including PLA2R, THSD7A, NELL1, PCDH7, NCAM1, SEMA3B, and HTRA1. Kidney biopsy specimens showed IgG (2 to 3+) with mild C3 (0 to 1+) along the GBM; IgG4 was the dominant IgG subclass. IHC after protease digestion and confocal IF confirmed granular FAT1 deposits along the GBM. Lastly, Western blot analyses detected anti-FAT1 IgG and IgG4 in the eluate obtained from pooled frozen kidney biopsy tissue and in the serum of those with FAT1-asssociated MN, but not from those with PLA2R-associated MN.

CONCLUSIONS

FAT1-associated MN appears to be a unique type of MN associated with HSCT. FAT1-associated MN represents a majority of MN associated with HSCT.

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.

[Schwannoma:Update on Molecular Profiling and Therapeutic Advances]

Schwannoma is a tumor that develops from the Schwann cells in the peripheral nervous system or cranial nerves. Gamma Knife radiosurgery has become an accepted treatment for schwannoma, with a high rate of tumor control. For sporadic or neurofibromatosis type 2-associated schwannoma resistant to radiotherapy, vascular endothelial growth factor(VEGF)-A/VEGF receptor(VEGFR)-targeted therapy(e.g., bevacizumab)may become the first-line therapy. However, some aspects of treatment with bevacizumab are problematic, such as the need for frequent parenteral administration, side effects, apparent drug resistance, and rebound tumor progression after cessation. In these situations, the gene product of the SH3PXD2A-HTRA1 fusion and several protein tyrosine kinase inhibitors may be supportive in preventing tumor progression because merlin inhibits signaling by tyrosine receptor kinases and there is activation of downstream pathways, including the Ras/Raf/MEK/ERK and PI3K/Akt/mTORC1 pathways. Although the tumor-microenvironment(TME)plays a key role in tumor growth, this physiological state is unclear in schwannoma. Tumor-associated macrophages may be a major component of the immunosuppressive cells in the TME of schwannoma. To impede tumor growth, the TME is also explored as a potential therapeutic target. Multimodal therapy is required to manage patients with refractory schwannoma. Furthermore, basic scientific research may be essential in achieving a novel treatment strategy.

Phase 1 Study of the Anti-HtrA1 Antibody-binding Fragment FHTR2163 in Geographic Atrophy Secondary to Age-related Macular Degeneration

PURPOSE

FHTR2163 is a novel antigen-binding fragment (Fab) directed against high-temperature requirement protein A1 (HtrA1). HTRA1 inhibition may preserve retinal integrity and slow disease progression in geographic atrophy (GA) secondary to age-related macular degeneration (AMD). This study examined the safety, pharmacokinetics, immunogenicity, and changes in the HTRA1-specific substrate Dickkop-related protein 3 (DKK3) in patients with GA who received FHTR2163.

DESIGN

Phase I, open-label, single ascending dose escalation and multiple-dose expansion study.

METHODS

Adults aged ≥ 50 years with GA secondary to AMD with best corrected visual acuity ranging between Snellen 20/125 and 20/400 were enrolled. In the first stage, a single intravitreal injection of FHTR2163 was given in 5 dose-escalation cohorts ranging from 1 to 20 mg (n = 3 patients/cohort; n = 15 total patients). The second stage evaluated the maximum tested dose of 20 mg administered every 4 weeks for 3 doses (n = 13 patients).

RESULTS

No dose limiting toxicities or ocular serious AEs were reported. The most frequently reported AEs in the study eye were conjunctival hemorrhage (n = 7), conjunctival hyperemia (n = 4), and eye pain (n = 2). No non-ocular or ocular AEs were assessed as drug related. There were no clinically significant changes in ocular exams. A sustained pharmacodynamic effect of anti-HtrA1 was observed in the aqueous humor, as measured by levels of cleaved DKK3.

CONCLUSIONS

FHTR2163, a novel Fab directed against HtrA1, was well tolerated with no DLTs or significant ocular AEs. The molecule when injected intravitreally for 3 doses showed a sustained pharmacodynamic effect at the maximum tested dose of 20 mg.

Post-hoc analysis of single nucleotide polymorphism profile for eyes with vascularized pigment epithelial detachment due to ARMD

INTRODUCTION

This post-hoc case-control study compares single nucleotide polymorphism (SNP) profile of eyes with vascularized pigment epithelial detachment (vPED) due to age-related macular degeneration (ARMD) with: (1) Control-1 eyes (no ARMD and AREDS Severity Scale 0); and (2) Control-2 eyes (drusen or AREDS Severity Scale 2). SNP profile of High Responders (HR) was also compared with Low Responders (LR) to ranibizumab.

METHODS

Blood samples from 40 patients with vPED treated with ranibizumab were sent for SNP-specific genotype analysis for comparison of variant allele frequencies of 23 SNPs associated with ARMD (VAF) to VAF in 184 Control-1 eyes, and VAF in 85 Control-2 eyes. VAF of HR-50 (⩾50% decrease in PED height) and VAF of HR-75 (⩾75% decrease in PED height) were also compared with VAF of LR.

RESULTS

These SNPs were more frequent in vPED than Control-1 eyes: APOE rs4420638 (A/G), HTRA1 rs104904924 (G/T), VEGF rs943080 (T/C), CFH rs1061170 (T/C), CFH rs2274700 (C/T), CFH rs10737680 (A/C), CFH rs10801555 (G/A). These SNPs were more frequent in vPED than Control-2 eyes: APOE rs4420638 (A/G), CFI rs4698775 (G/T), COL15A1/TGFBR1 rs334353 (T/G). FRK rs3812111 (T/A) was more frequent in HR-50 and HR-75 eyes compared with LR.

CONCLUSION

Seven SNPs were more frequent in vPED eyes than non-ARMD eyes, and three SNPs were more frequent in vPED eyes than drusen eyes. Adjusting for multiplicity, only CFH rs2274700 (C/T) was significant for first comparison, and only COL15A1/TGFBR1 rs334353 (T/G) was significant for second comparison. APOE rs4420638 (A/G) was the single SNP more frequently linked to vPED eyes for both comparisons. FRK rs3812111 (T/A) was consistently associated with high responders.

Nonclinical Safety Assessment of FHTR2163, An Antigen-Binding Fragment Against HTRA1 for the Treatment of Geographic Atrophy

FHTR2163 is an antigen-binding fragment of a humanized immunoglobulin G1 monoclonal antibody directed against high-temperature requirement A serine peptidase 1 (HTRA1) that is being developed as a potential intravitreal (ITV) treatment for patients with geographic atrophy (GA), an advanced form of dry age-related macular degeneration. The nonclinical toxicology program was designed to assess the safety and tolerability of HTRA1 inhibition following ITV administration of FHTR2163 to support ITV administration in patients with GA. FHTR2163 was well tolerated in a single-dose ITV-administered 8-day toxicity study in cynomolgus monkeys following a 50 µL high (>700 mOsm/kg) osmolality formulation up to 12.5 mg/eye; however, 100 µL (2× 50 µL injections) of a high-osmolality formulation resulted in transient retinal detachment. Repeat-dose ITV administration every 2 weeks of FHTR2163 was well tolerated in 8- and 26-week studies with ITV injection of 100 µL (2× 50 μL) of iso-osmolar formulation up to 15 mg/eye, or 50 µL of the high-osmolality formulation up to 12.5 mg/eye. Observed transient and reversible ocular effects included inflammation and perivascular infiltrates, consistent with an immune response attributed to the administration of heterologous (humanized) protein. Overall, FHTR2163 was well tolerated, and the nonclinical package supported the continued clinical development of FHTR2163 in patients with GA.

Hypothetical pathogenesis of age-related macular degeneration and pachychoroid diseases derived from their genetic characteristics

Genetic studies have investigated the pathogenesis of age-related macular degeneration (AMD). The pachychoroid concept has recently garnered attention as a possible explanation for AMD pathogenesis; the genetic characteristics of pachychoroid diseases have also been elucidated. In this review, we summarize previously reported genetic characteristics of AMD and pachychoroid diseases, and analyze these data to understand the pathogenesis of AMD and pachychoroid diseases. Previous studies show that VIPR2 and the CFH I62V A allele promote development of pachychoroid and central serous chorioretinopathy (CSC), while the CFH I62V G allele promotes development of drusen, pachychoroid neovasculopathy (PCN/PNV), and AMD. ARMS2/HTRA1 also promotes development of drusen, PCN/PNV, and AMD. TNFRSF10A and GATA5 are associated with CSC but not with pachychoroid, and TNFRSF10A is associated with AMD that includes PCN/PNV. These genetic characteristics suggest the following mechanisms of developing AMD and pachychoroid diseases. VIPR2 and the CFH I62V A allele promote pachychoroid development, which can result in CSC development. The CFH I62V G allele promotes a common step during PCN/PNV and AMD development induced by pachychoroid or drusen, such as damage of Bruch's membrane or retinal pigment epithelium (RPE). ARMS2/HTRA1 also promotes damage of Bruch's membrane or RPE, while the association with drusen formation is stronger in ARMS2/HTRA1 than in CFH. TNFRSF10A and GATA5 promote blood-retinal-barrier breakdown to induce CSC, which could lead to PCN/PNV development. Furthermore, recently reported genetic associations with the natural course of CSC suggest the importance of reconsidering the subtype classification of CSC. These associations would enable the development of personalized/precision medicine for CSC and.

[Identify the Molecular Target of Diffuse Large B Cell Lymphoma by Bioinformatics Analysis]

OBJECTIVE

To identify the molecular pathogenesis of diffuse large B cell lymphoma (DLBCL) and to screen potential biomarkers or therapeutic targets for diagnosis, treatment and prognosis evaluation of patients with DLBCL.

METHODS

Gene expression profiles of GSE56315 were downloaded from GEO database. Analysis of differentially expressed genes (DEGs) in the microarray was performed using"R"software. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses of up-regulated DEGs were performed using DAVID database. The survival analysis of up-regulated DEGs was performed using GEPIA database.

RESULTS

There were 55 DLBCL biopsy tissue specimes and 33 normal tonsil tissue specimes in the datasets. A total of 2001 differentially expressed genes were identified, including 1 079 up-regulated DEGs and 922 down-regulated DEGs. Function enrichment analysis indicated that the up-regulated DEGs were involved in 425 GO terms, including 31 genes of FDR＜0.05 (P＜0.05) and 17 pathways. In the GEPIA database, the expression levels of 12 up-regulated DEGs (AK8、AP2M1、ATOX1、 CSF2RA、CYP27A1、HEBP1、HTRA1、HTRA4、IGFBP3、PTGDS、SIGLEC15、UQCRC1) were found to be significantly correlated with shorter overall survival of DLBCL patients.

CONCLUSION

The internal biological information in DLBCL revealed by integrative bioinformatical analysis may provide an important theoretical basis for further research on molecular mechanism of DLBCL, screening of potential therapeutic targets and evaluation of prognosis.

The Persistence of Privilege for a Healthy Retina

A minor haplotype of chromosome 10q26 accounts for much of the genetic risk of age-related macular degeneration (AMD). In this issue of Immunity, Beguier et al. demonstrate that carriers of the 10q26 AMD-risk haplotype overexpress the peptidase HTRA1, which in turns results in mononuclear phagocyte persistence in an immune privileged site and pathogenic inflammation.

Tetrandrine partially reverses multidrug resistance of human laryngeal cancer cells

OBJECTIVE

Studies have demonstrated that tetrandrine reverses multidrug resistance (MDR) in animal models or cell lines derived from multiple cancer types. We examined the potential MDR reversal activity of tetrandrine in a multidrug-resistant variant of a human laryngeal cancer Hep-2 cell line and explored potential mechanisms involved.

METHODS

We developed the multidrug-resistant variant cell line (Hep-2/v) by exposing Hep-2 cells to stepwise increasing concentrations of vincristine (VCR). After Hep-2 or Hep-2/v cells were treated with tetrandrine (2.52 µg/mL), MDR was measured by MTT assay, rhodamine 123 retention was measured by flow cytometry, and mRNA and protein expression of multidrug resistance 1 (MDR1), regulator of G-protein signaling 10 (RGS10), high-temperature requirement protein A1 (HTRA1), and nuclear protein 1 (NUPR1) were detected by real-time reverse transcription-PCR and western blotting, respectively.

RESULTS

Tetrandrine significantly lowered the half-maximal inhibitory concentration (IC50) of VCR in Hep-2/v cells, resulting in a 2.22-fold reversal of MDR. Treatment with tetrandrine increased rhodamine 123 retention, downregulated the mRNA and protein expression of MDR1 and RGS10, and upregulated expression of HTRA1 in Hep-2/v cells.

CONCLUSION

We showed that tetrandrine exerts anti-MDR activity in Hep-2/v cells, possibly by inhibiting MDR1 overexpression-mediated drug efflux and by altering expression of HTRA1 and RGS10.

Monogenic cerebral small-vessel diseases: diagnosis and therapy. Consensus recommendations of the European Academy of Neurology

BACKGROUND AND PURPOSE

Guidelines on monogenic cerebral small-vessel disease (cSVD) diagnosis and management are lacking. Endorsed by the Stroke and Neurogenetics Panels of the European Academy of Neurology, a group of experts has provided recommendations on selected monogenic cSVDs, i.e. cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL), autosomal dominant High Temperature Requirement A Serine Peptidase 1 (HTRA1), cathepsin-A-related arteriopathy with strokes and leukoencephalopathy (CARASAL), pontine autosomal dominant microangiopathy and leukoencephalopathy (PADMAL), Fabry disease, mitochondrial encephalopathy, lactic acidosis and stroke-like episodes (MELAS) and type IV collagen (COL4)A1/2.

METHODS

We followed the Delphi methodology to provide recommendations on several unanswered questions related to monogenic cSVD, including genetic testing, clinical and neuroradiological diagnosis, and management.

RESULTS

We have proposed 'red-flag' features suggestive of a monogenic disease. General principles applying to the management of all cSVDs and specific recommendations for the individual forms of monogenic cSVD were agreed by consensus.

CONCLUSIONS

The results provide a framework for clinicians involved in the diagnosis and management of monogenic cSVD. Further multicentre observational and treatment studies are still needed to increase the level of evidence supporting our recommendations.

Macrophage migration inhibitory factor (MIF) modulates trophic signaling through interaction with serine protease HTRA1

Macrophage migration inhibitory factor (MIF), a small conserved protein, is abundant in the immune- and central nervous system (CNS). MIF has several receptors and binding partners that can modulate its action on a cellular level. It is upregulated in neurodegenerative diseases and cancer although its function is far from clear. Here, we report the finding of a new binding partner to MIF, the serine protease HTRA1. This enzyme cleaves several growth factors, extracellular matrix molecules and is implicated in some of the same diseases as MIF. We show that the function of the binding between MIF and HTRA1 is to inhibit the proteolytic activity of HTRA1, modulating the availability of molecules that can change cell growth and differentiation. MIF is therefore the first endogenous inhibitor ever found for HTRA1. It was found that both molecules were present in astrocytes and that the functional binding has the ability to modulate astrocytic activities important in development and disease of the CNS.

Association between polymorphism rs11200638 in the HTRA1 gene and the response to anti-VEGF treatment of exudative AMD: a meta-analysis

BACKGROUND

Anti-angiogenesis treatments are the most commonly used treatments for the vision loss caused by exudative age-related macular degeneration (AMD), in which the anti-vascular endothelial growth factor (VEGF) drugs with ranibizumab and bevacizumab are current standard treatments. However, the outcome of anti-VEGF therapeutics is not uniform in all patients.

METHODS

We performed a literature-based meta-analysis including, five published studies relevant to HTRA1 and response to anti-VEGF treatment (bevacizumab or ranibizumab). Summary odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using fixed- and random-effects models. Sensitivity analysis and meta-regression were also performed. Q-statistic test and Egger's test was used to evaluate heterogeneity and publication bias respectively.

RESULTS

Overall, no association between the rs11200638 polymorphism in HTRA1 gene and the anti-VEGF treatment response was found in the genotype GG versus AA (OR = 1.06; 95% CI: 0.77 to 1.48; P = 0.98), genotype GA versus AA (OR = 1.11; 95% CI: 0.83 to 1.47; P = 0.93), genotype GG + GA versus AA (OR = 1.22; 95% CI: 0.94 to 1.57; P = 0.09), and allele G versus A (OR = 0.92; 95% CI: 0.78 to 1.08; P = 0.14). In the subgroup analysis by ethnicity Caucasian population, and a significant association was still not observed in all genetic models. Sensitivity analysis indicated the robustness of our findings, and no publication bias was observed in our meta-analysis.

CONCLUSIONS

This study shows that there was no association between the polymorphism rs11200638 in HTRA1 gene and response to anti-VEGF treatment of exudative AMD. However, more studies are needed to further prove the conclusion of present study, especially well-designed and high quality randomised controlled trials or intervention studies.

Variable effect of maternal oral glucose load on circulating cell-free placental mRNAs

BACKGROUND

It is not known whether fasting affects levels of circulating placenta-specific transcripts.

OBJECTIVE

To assess whether a glucose load affects circulating placenta-specific transcripts.

METHOD

RNA was extracted from paired blood samples (fasting and 1-h post 75 g oral glucose) from 22 women. Placenta-specific genes were measured by RT-qPCR.

RESULTS

There was no change in ADM, CSH1, PAPPA2, PSG1 or TAC3 expression between fasting and post-glucose states. However, HTRA1 decreased after glucose load.

CONCLUSION

Maternal fasting state does not influence expression of the majority of placenta-specific genes but may need to be accounted for when validating biomarkers of placental disease.

Recombinant Haplotypes Narrow the ARMS2/HTRA1 Association Signal for Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is the leading cause of blindness in ageing societies, triggered by both environmental and genetic factors. The strongest genetic signal for AMD with odds ratios of up to 2.8 per adverse allele was found previously over a chromosomal region in 10q26 harboring two genes, ARMS2 and HTRA1, although with little knowledge as to which gene or genetic variation is functionally relevant to AMD pathology. In this study, we analyzed rare recombinant haplotypes in 16,144 AMD cases and 17,832 controls from the International AMD Genomics Consortium and identified variants in ARMS2 but not HTRA1 to exclusively carry the AMD risk with P-values between 1.0 × 10-773 and 6.7 × 10-5 This now allows prioritization of the gene of interest for subsequent functional studies.

HTRA1 and TGF-β1 Concentrations in the Aqueous Humor of Patients With Neovascular Age-Related Macular Degeneration

Purpose

The purpose of this study was to evaluate the expression of high-temperature requirement A serine peptidase 1 (HTRA1), TGF-β1, bone morphogenetic protein 4 (BMP4), growth differentiation factor 6 (GDF6), and VEGFA proteins in the aqueous humor of patients with naïve choroidal neovascularization (nCNV) secondary to AMD.

Methods

We measured by ELISA the concentrations of HTRA1, TGF-β1, BMP4, GDF6, and VEGFA in the aqueous humor of 23 patients affected by nCNV who received three consecutive monthly intravitreal injections of 0.5 mg ranibizumab. Samples were collected at baseline (before the first injection), month 1 (before the second injection), and month 2 (before the third injection). Twenty-three age-matched cataract patients served as controls.

Results

Bone morphogenetic protein 4 and GDF6 were not detectable in any samples. Baseline HTRA1 was higher than controls (P < 0.0001) and higher than both the month 1 (P < 0.0001) and the month 2 (P < 0.0001) values. Baseline VEGFA was higher than controls (P < 0.0001), not different from month 1 value (P = 0.0821), but higher than month 2 value (P < 0.0001). Baseline TGF-β1 was higher than controls (P = 0.0015) and not different from month 1 (P = 0.129) and month 2 values (P = 0.5529). No correlation was found in naïve patients between concentrations of HTRA1 and TGF-β1, HTRA 1 and VEGFA, or TGF-β1 and VEGFA.

Conclusions

In nCNV patients, HTRA1 and TGF-β1 were significantly higher compared to controls. After treatment, TGF-β1 was persistently elevated, while HTRA1 returned to control levels, suggesting the involvement of TGF-β1 and HTRA1 in neovascular AMD and a VEGFA-independent role for TGF-β1.

Protective effects of an HTRA1 insertion-deletion variant against age-related macular degeneration in the Chinese populations

Age-related macular degeneration (AMD) is a leading cause of visual impairment and irreversible blindness in most developed countries, affecting about 50 million elderly people worldwide. Retinal pigment epithelial (RPE) cell degeneration is the pathophysiological cause of AMD, leading to geographic atrophy and choroidal neovascularization. We and others have previously identified several polymorphisms on chromosome 10q26 (HTRA1 rs11200638 as well as LOC387715 rs10490924 and c.372_815del443ins54) associated with AMD. In this study, we confirmed the association of our previously identified HTRA1 insertion-deletion (indel) variant (c.34delCinsTCCT) in 195 exudative AMD patients and 390 controls from the Hong Kong Chinese cohort with additional 168 patients and 210 controls from the Chengdu Chinese cohort and followed by studying its biological functions in RPE cells. Genetic analysis verified the higher prevalence of c.34delCinsTCCT allele in control subjects (8.0%) than in AMD patients (1.9%; P=7.87 × 10-5, odds ratio=0.229). This protective effect was validated as the haplotype of the c.34delCinsTCCT allele existed independent of the risk haplotype (P=1.17 × 10-5). In vitro studies showed that recombinant HTRA1 c.34delCinsTCCT variant protein was more localized in the endoplasmic reticulum of RPE cells compared with the wild-type protein, and its secretion was delayed. Moreover, ARPE-19 cells expressing HTRA1 c.34delCinsTCCT variant had higher cell viability, lower cell apoptosis and were less responsive to anoikis, supporting its protective role. We revealed a protective AMD-associated HTRA1 variant in Chinese populations and the biological role of HTRA1 in RPE cell degeneration, indicating its involvement in AMD pathogenesis.

[Cerebral Autosomal Recessive Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CARASIL)]

Cerebral small vessel disease (CSVD) is frequently observed among the elderly and is known to cause dementia and gait disturbance associated with white matter lesions, lacunar infarcts, and cerebral hemorrhage. Molecular mechanistic studies promise to provide new insights into the pathogenesis of hereditary CSVD. Cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL) is one of the hereditary CSVDs caused by a mutation in the high-temperature requirement serine peptidase A1 (HTRA1) gene. The loss of HTRA1 protease activity increases signaling via transforming growth factor (TGF)β, thereby resulting in CARASIL. Although the CARASIL has been characterized by juvenile onset alopecia and spondylosis deformans, these features are not always observed in individuals with an HTRA1 mutation. Moreover, some HTRA1 mutations cause CSVD in heterozygous states. Therefore, the clinical features of CSVD resulting from an HTRA1 mutation extend to patients with CSVD alone or to those with dominantly inherited CSVD.

High temperature requirement A1 and fibronectin: two possible players in placental tissue remodelling

High temperature requirement A1 (HtrA1) is a secreted protease involved in placental development. Fibronectin (FN) is involved in important process such as wound healing, cell adhesion and spreading, growth, migration, and differentiation. The purpose of this study was to analyse the expression patterns of HtrA1 in relationship to FN and to the key growth zones of placenta such as mesenchymal villi as well as cell islands and cell columns. We demonstrated that FN and HtrA1 are localized in the placental key growth zones suggesting a pivotal role in maintaining the balance among the molecules involved in the placental development and differentiation.

The differential role of HTRA1 in HPV-positive and HPV-negative cervical cell line proliferation

BACKGROUND

High-risk human papillomaviruses (HPVs) are strongly associated with the development of some malignancies. The E6 and E7 viral oncoproteins are the primary proteins responsible for cell homeostasis alteration and immortalization. Furthermore, the E6 protein from high-risk HPVs can interact with the PDZ (PSD-90/Dlg/ZO-1) domains of cellular proteins, triggering cell transformation. One protein that is associated with pathological conditions and has a PDZ domain is the protease HTRA1 (high temperature requirement 1). This protein is poorly expressed in some cancers, suggesting a tumor suppressor role. The aim of this study was to evaluate the effect of HTRA1 overexpression in HPV16-positive (CasKi) and HPV-negative (C33) cervical cell lines.

METHODS

The cells were transfected with a vector containing the HTRA1 ORF or an empty vector. HTRA1 overexpression was confirmed by qRT-PCR. The cells were subjected to cell proliferation, colony formation, apoptosis and cell cycle assays.

RESULTS

C33 cells expressing HTRA1 grew significantly fewer colonies and showed less proliferation than cells without HTRA1 expression. In contrast, in the CasKi cells overexpressing HTRA1, there was an increase in the cell growth rate and in the colonies density compared to cells expressing low levels of HTRA1. An apoptosis assay showed that HTRA1 does not interfere with the apoptosis rate in these cells. A cell cycle immunofluorescence assay revealed more CasKi cells overexpressing HTRA1 in the S phase and more C33 HTRA1-transfected cells in the G0/G1 phase, suggesting that HTRA1 plays different roles in the cell cycle progression of these cells.

CONCLUSIONS

HTRA1 overexpression prevents cell proliferation in the HPV-negative cell line and increases cell proliferation in the HPV-positive cell line. Although the E6/HTRA1 interaction has already been described in the literature, more studies are required to confirm whether the present functional findings are a result of this interaction.

The genomic landscape of schwannoma

Schwannomas are common peripheral nerve sheath tumors that can cause debilitating morbidities. We performed an integrative analysis to determine genomic aberrations common to sporadic schwannomas. Exome sequence analysis with validation by targeted DNA sequencing of 125 samples uncovered, in addition to expected NF2 disruption, recurrent mutations in ARID1A, ARID1B and DDR1. RNA sequencing identified a recurrent in-frame SH3PXD2A-HTRA1 fusion in 12/125 (10%) cases, and genomic analysis demonstrated the mechanism as resulting from a balanced 19-Mb chromosomal inversion on chromosome 10q. The fusion was associated with male gender predominance, occurring in one out of every six men with schwannoma. Methylation profiling identified distinct molecular subgroups of schwannomas that were associated with anatomical location. Expression of the SH3PXD2A-HTRA1 fusion resulted in elevated phosphorylated ERK, increased proliferation, increased invasion and in vivo tumorigenesis. Targeting of the MEK-ERK pathway was effective in fusion-positive Schwann cells, suggesting a possible therapeutic approach for this subset of tumors.

Association of frailty with the serine protease HtrA1 in older adults

Frailty is a geriatric syndrome characterized by multi system dysregulation. It has been suggested that chronic inflammation may be involved in the pathogenesis of frailty. No study so far has identified accurate, specific and sensitive molecular biomarkers for frailty. High-temperature requirement serine protease A1 (HtrA1) is a secreted multidomain serine protease implicated in the inhibition of signaling of active transforming growth factor-β (TGF-β)1, a cytokine which has an important anti-inflammation role. The aim of the present study was to investigate the association of circulating levels of HtrA1 with frailty in a sample of older adults. The study was performed in 120 older adults aged >65years and admitted to a geriatric outpatient clinic. The frailty status of participants was assessed by both the Fried's criteria (physical frailty, PF) and a modified Rockwood's frailty index (FI). Plasma HtrA1 concentration was measured using commercial ELISA kit. Frailty was identified in 61/120 participants (50.8%) using PF, and in 60/118 subjects (50.8%) using FI. Plasma levels of HtrA1 were significantly higher in individuals classified as frail according to PF (75.9ng/mL, 95% CI 67.4-85.6) as compared with non-frail participants (48.4ng/mL, 95% CI 42.5-54.6, p<0.001). A significant association was also observed between frailty, assessed by FI, and HtrA1 levels (72.2ng/mL, 95% CI 63.4-82.3, vs. 50.4ng/mL, 95% CI 44.3-58.0, p<0.001). These associations were confirmed after adjusting for potential confounders. This study demonstrates for the first time the association of plasma levels of HtrA1 with frailty status. Future investigations are needed to validate the potential value of HtrA1 as possible biomarker for frailty.

Analysis of copy number variation at DMBT1 and age-related macular degeneration

BACKGROUND

DMBT1 is a gene that shows extensive copy number variation (CNV) that alters the number of bacteria-binding domains in the protein and has been shown to activate the complement pathway. It lies next to the ARMS2/HTRA1 genes in a region of chromosome 10q26, where single nucleotide variants have been strongly associated with age-related macular degeneration (AMD), the commonest cause of blindness in Western populations. Complement activation is thought to be a key factor in the pathogenesis of this condition. We sought to investigate whether DMBT1 CNV plays any role in the susceptibility to AMD.

METHODS

We analysed long-range linkage disequilibrium of DMBT1 CNV1 and CNV2 with flanking single nucleotide polymorphisms (SNPs) using our previously published CNV and HapMap Phase 3 SNP data in the CEPH Europeans from Utah (CEU). We then typed a large cohort of 860 AMD patients and 419 examined age-matched controls for copy number at DMBT1 CNV1 and CNV2 and combined these data with copy numbers from a further 480 unexamined controls.

RESULTS

We found weak linkage disequilibrium between DMBT1 CNV1 and CNV2 with the SNPs rs1474526 and rs714816 in the HTRA1/ARMS2 region. By directly analysing copy number variation, we found no evidence of association of CNV1 or CNV2 with AMD.

CONCLUSIONS

We have shown that copy number variation at DMBT1 does not affect risk of developing age-related macular degeneration and can therefore be ruled out from future studies investigating the association of structural variation at 10q26 with AMD.

A Phenotyping Regimen for Genetically Modified Mice Used to Study Genes Implicated in Human Diseases of Aging

Age-related diseases are becoming increasingly prevalent and the burden continues to grow as our population ages. Effective treatments are necessary to lessen the impact of debilitating conditions but remain elusive in many cases. Only by understanding the causes and pathology of diseases associated with aging, can scientists begin to identify potential therapeutic targets and develop strategies for intervention. The most common age-related conditions are neurodegenerative disorders such as Parkinson's disease and blindness. Age-related macular degeneration (AMD) is the leading cause of blindness in the elderly. Genome wide association studies have previously identified loci that are associated with increased susceptibility to this disease and identified two regions of interest: complement factor H (CFH) and the 10q26 locus, where the age-related maculopathy susceptibility 2 (ARMS2) and high-temperature requirement factor A1 (HtrA1) genes are located. CFH acts as a negative regulator of the alternative pathway (AP) of the complement system while HtrA1 is an extracellular serine protease. ARMS2 is located upstream of HtrA1 in the primate genome, although the gene is absent in mice. To study the effects of these genes, humanized knock-in mouse lines of Cfh and ARMS2, knockouts of Cfh, HtrA1, HtrA2, HtrA3 and HtrA4 as well as a conditional neural deletion of HtrA2 were generated. Of all the genetically engineered mice produced only mice lacking HtrA2, either systemically or in neural tissues, displayed clear phenotypes. In order to examine these mice thoroughly and systematically, an initial phenotyping schedule was established, consisting of a series of tests related to two main diseases of interest: AMD and Parkinson's. Genetically modified mice can be subjected to appropriate experiments to identify phenotypes that may be related to the associated diseases in humans. A phenotyping regimen with a mitochondrial focus is presented here alongside representative results from the tests of interest.

Epigenetic silencing of serine protease HTRA1 drives polyploidy

BACKGROUND

Increased numbers and improperly positioned centrosomes, aneuploidy or polyploidy, and chromosomal instability are frequently observed characteristics of cancer cells. While some aspects of these events and the checkpoint mechanisms are well studied, not all players have yet been identified. As the role of proteases other than the proteasome in tumorigenesis is an insufficiently addressed question, we investigated the epigenetic control of the widely conserved protease HTRA1 and the phenotypes of deregulation.

METHODS

Mouse embryonal fibroblasts and HCT116 and SW480 cells were used to study the mechanism of epigenetic silencing of HTRA1. In addition, using cell biological and genetic methods, the phenotypes of downregulation of HTRA1 expression were investigated.

RESULTS

HTRA1 is epigenetically silenced in HCT116 colon carcinoma cells via the epigenetic adaptor protein MBD2. On the cellular level, HTRA1 depletion causes multiple phenotypes including acceleration of cell growth, centrosome amplification and polyploidy in SW480 colon adenocarcinoma cells as well as in primary mouse embryonic fibroblasts (MEFs).

CONCLUSIONS

Downregulation of HTRA1 causes a number of phenotypes that are hallmarks of cancer cells suggesting that the methylation state of the HtrA1 promoter may be used as a biomarker for tumour cells or cells at risk of transformation.

Distinct molecular mechanisms of HTRA1 mutants in manifesting heterozygotes with CARASIL

OBJECTIVE

To elucidate the molecular mechanism of mutant HTRA1-dependent cerebral small vessel disease in heterozygous individuals.

METHODS

We recruited 113 unrelated index patients with clinically diagnosed cerebral small vessel disease. The coding sequences of the HTRA1 gene were analyzed. We evaluated HTRA1 protease activities using casein assays and oligomeric HTRA1 formation using gel filtration chromatography.

RESULTS

We found 4 heterozygous missense mutations in the HTRA1 gene (p.G283E, p.P285L, p.R302Q, and p.T319I) in 6 patients from 113 unrelated index patients and in 2 siblings in 2 unrelated families with p.R302Q. The mean age at cognitive impairment onset was 51.1 years. Spondylosis deformans was observed in all cases, whereas alopecia was observed in 3 cases; an autopsied case with p.G283E showed arteriopathy in their cerebral small arteries. These mutant HTRA1s showed markedly decreased protease activities and inhibited wild-type HTRA1 activity, whereas 2 of 3 mutant HTRA1s reported in cerebral autosomal-recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL) (A252T and V297M) did not inhibit wild-type HTRA1 activity. Wild-type HTRA1 forms trimers; however, G283E and T319I HTRA1, observed in manifesting heterozygotes, did not form trimers. P285L and R302Q HTRA1s formed trimers, but their mutations were located in domains that are important for trimer-associated HTRA1 activation; in contrast, A252T and V297M HTRA1s, which have been observed in CARASIL, also formed trimers but had mutations outside the domains important for trimer-associated HTRA1 activation.

CONCLUSIONS

The mutant HTRA1s observed in manifesting heterozygotes might result in an impaired HTRA1 activation cascade of HTRA1 or be unable to form stable trimers.

The presence of CFH, HTRA1, ARMS2, VEGF-A and VEGF-R and the appearance of age-related macular degeneration sub-types

OBJECTIVE

To demonstrate the genetic influence in the onset of the different age-related macular disease (AMD) subtypes by analysing the genotype distribution of CFH, ARMS2, HTRA1, VEGF-A and VEGF-R polymorphisms in patients with neovascular and atrophic AMD.

MATERIALS AND METHODS

The study was conducted on 101 consecutive patients with AMD diagnosis (74 exudative, 27 atrophic) following Wisconsin international classification criteria. The CFH rs1410996, ARMS2 rs10940923, VEGF-A rs833061, rs699947, and VEGF-R rs2071559 polymorphisms were analysed using real time PCR with taqman probes, and HTRA1 rs112000638 using restriction endonucleases digestion. A study was made of the genotype distribution of the different polymorphisms in our group of patients with neovascular AMD and those with the atrophic type, and a comparison was made of the results for each one of the genes studied.

RESULTS

No statistically significant differences (P>.05) were found in the genotype distribution of the different polymorphisms between patients with neovascular AMD and patients with atrophic AMD in our population, although the "risk" genotypes tended to appear more frequently in patients with neovascular AMD, despite the lack of statistical significance.

CONCLUSIONS

Allelic variants of CFH, ARMS2, HTRA1, VEGF-A or VEGF-R genes are not associated with the different AMD subtypes. This suggests that, although the polymorphisms seem to be associated with the disease susceptibility, they are not involved in the onset of the different clinical variants of AMD. Further studies in different populations, and with a larger cohort of patients, are needed to confirm these results.

Structure-Based Design of a Br Halogen Bond at the Complex Interface of the Human Placental HtrA1 PDZ Domain with Its Heptapeptide Ligand

The shock-induced serine protease HtrA1 is a potential regulator of human placenta development during pregnancy. The protein contains a functional PDZ domain that has been solved in complex with a phage display-derived heptapeptide: Asp-6 Ser-5 Arg-4 Ile-3 Trp-2 Trp-1 Val0 . In this study, a rationally designed halogen bond was introduced to the domain-peptide complex based on its NMR structure in solution. We computationally compared the stabilization energies and hindrance effects due to the presence of different halogens X (X = F, Cl, Br, or I), using a hybrid quantum mechanics/molecular mechanics (QM/MM) approach, and found that the Br atom could considerably promote the peptide binding free energy (ΔΔG = -5.2 kcal/mol). Fluorescence assays confirmed that the peptide affinity to the HtrA1 PDZ domain was improved by approximately sevenfold upon bromination. Structural analysis identified a geometrically perfect halogen bond between the Br atom of the peptide Trp-1 residue and the carbonyl O atom of the HtrA1 Ile385 residue, with a bond length and an interaction energy of d = 3.20 Å and ΔE = -3.7 kcal/mol, respectively.

Dietary folate, B vitamins, genetic susceptibility and progression to advanced nonexudative age-related macular degeneration with geographic atrophy: a prospective cohort study

BACKGROUND

There is growing evidence of the importance of nutrition in age-related macular degeneration (AMD), but few studies have explored associations with folate and B vitamins. No effective therapeutic strategy for geographic atrophy (GA) is available, and prevention could be of great value.

OBJECTIVE

We investigated associations between dietary folate, B vitamins, and progression to GA and whether these associations might be modified by genetic susceptibility.

DESIGN

Among 2525 subjects (4663 eyes) in the Age-Related Eye Disease Study, 405 subjects (528 eyes) progressed to GA over 13 y. Folate and B vitamins were log transformed and calorie adjusted separately for men and women. Ten loci in 7 AMD genes [complement factor H, age-related maculopathy susceptibility 2/high-temperature requirement A serine peptidase 1, complement component 2, complement component 3, complement factor B, collagen type VIII α 1, and RAD51 paralog B] were examined. Survival analysis was used to assess associations between incident GA and dietary intake of folate and B vitamins. Interaction effects between these nutrients and genetic variation on AMD risk were also evaluated. Subjects with at least one eye free of advanced AMD at baseline were included in these analyses.

RESULTS

There was a reduced risk of progression to GA with increasing intake of thiamin, riboflavin, and folate after adjusting for age, sex, and total energy intake (P-trend = 0.01, 0.03, and 0.001, respectively). After adjustment for demographic, behavioral, ocular, and genetic covariates, trends remained statistically significant for folate (P-trend = 0.007) and were borderline for thiamin (P-trend = 0.05). Riboflavin did not retain statistical significance (P-trend = 0.20). Folate was significantly associated with lower risk of incident GA among subjects homozygous for the complement component 3 (C3) R102G rs2230199 nonrisk genotype (CC) (HR = 0.43; 95% CI: 0.27, 0.70; P = 0.0005) but not subjects carrying the risk allele (G) (P = 0.76). Neither folate nor any B vitamin was significantly associated with neovascular AMD.

CONCLUSIONS

High folate intake was associated with a reduced risk of progression to GA. This relation could be modified by genetic susceptibility, particularly related to the C3 genotype. This trial was registered at clinicaltrials.gov as NCT00594672.

[The expression of serine protease HtrA1 in human periodontal ligament tissue and the effect of HtrA1 on the proliferation of human periodontal ligament cells]

OBJECTIVE

To observe the expression of serine protease HtrA1 in human periodontal ligament tissue and to explore the effect of HtrA1 on the proliferation of human periodontal ligament cells (hPDLC).

METHODS

Six human premolars and three human third molars(patient's ages ranging from 12 to 25, with intact root, without caries and/or periodontitis) were obtained in the Department of Maxillofacial Surgery of Wuhan University Hospital of Stomatology. Reverse transcription-PCR(RT-PCR) and immunohistochemistry analysis were applied to investigate the expression of HtrA1. Primary hPDLC were obtained by tissue-culture method in vitro. The proliferation of hPDLC was determined by methyl thiazolytetrazolium(MTT). Lentivirus-mediated over-expression and reduction of HtrA1 level was performed. An empty vector was used as negative control. On days 1, 3, 5, 7 and 9, the growth of hPDLC was characterized using cell counting kit-8(CCK-8) assay.

RESULTS

RT-PCR data indicated that HtrA1 mRNA was expressed in human periodontal ligament tissue. Immunohistochemistry analysis showed HtrA1 was expressed in human periodontal ligament, mainly in the cytoplasm of hPDLC and the extracellular matrix. The MTT result suggested that the growth curve was consistent with the growth characteristics of hPDLC. The stable over-expression and knockdown cell lines was successfully established by lentivirus with more than 90% transfection efficiency. CCK-8 assay showed that HtrA1 over-expression inhibited the proliferation of hPDLC(0.897±0.060, 0.890±0.083, 1.631±0.038, 1.111±0.041, 1.110±0.189), while cell proliferation increased after down-regulation of HtrA1(0.329±0.021, 0.529±0.044, 0.973±0.056, 1.626±0.102, 2.344±0.198)(P<0.05).

CONCLUSIONS

HtrA1 is expressed in human periodontal ligament tissue at both mRNA and protein levels, and may play an important role in regulating the proliferation of hPDLC.

Gene Structure of the 10q26 Locus: A Clue to Cracking the ARMS2/HTRA1 Riddle?

Age-related macular degeneration (AMD) is a sight-threatening disorder of the central retina. Being the leading cause of visual impairment in senior citizens, it represents a major public health issue in developed countries. Genetic studies of AMD identified two major susceptibility loci on chromosomes 1 and 10. The high-risk allele of the 10q26 locus encompasses three genes, PLEKHA1, ARMS2, and HTRA1 with high linkage disequilibrium and the individual contribution of the encoded proteins to disease etiology remains controversial. While PLEKHA1 and HTRA1 are highly conserved proteins, ARMS2 is only present in primates and can be detected by using RT-PCR. On the other hand, there is no unequivocal evidence for the existence of the encoded protein. However, it has been reported that risk haplotypes only affect the expression of ARMS2 (but not of HTRA1), making ARMS2 the best candidate for being the genuine AMD gene within this locus. Yet, homozygous carriers of a common haplotype carry a premature stop codon in the ARMS2 gene (R38X) and therefore lack ARMS2, but this variant is not associated with AMD. In this work we aimed at characterizing the diversity of transcripts originating from this locus, in order to find new hints on how to resolve this perplexing paradox. We found chimeric transcripts originating from the PLEKHA1 gene but ending in ARMS2. This finding may give a new explanation as to how variants in this locus contribute to AMD.

High temperature requirement A1, transforming growth factor beta1, phosphoSmad2 and Ki67 in eutopic and ectopic endometrium of women with endometriosis

Increasing evidence supports the hypothesis that TGFb1 signalling may be mediated by high temperature requirement A1 (HtrA1) serine protease, acting on important regulatory mechanisms such as cell proliferation and mobility. Evidence is now accumulating to suggest that HtrA1 is involved in the development and progression of several pathologies. The aim of this study was to evaluate: i) if HtrA1 and TGFb1 expressions differ in eutopic and ectopic endometrium in women with endometriosis; ii) if HtrA1 correlates to TGFb1, pSmad and Ki67. This study was carried out including 10 women with ovarian endometriosis (cases) and 10 women with non endometriotic diseases (controls). Endometrial tissue underwent immunohistochemical H-score analysis for HtrA1, TGFb1, pSmad and Ki67 molecules. Data evaluation was performed by a nonparametric Kruskal-Wallis test and Spearman correlation was applied to evaluate the relationship among the molecules investigated in the epithelial and in the stromal compartment. The HtrA1 was significant decreased in ectopic and eutopic endometrium of women with endometriosis when compared with control endometrium in epithelial compartment. TGFb1was significantly increased in eutopic endometrium and decreased in ectopic endometrium in epithelial and stromal compartment. In addition, Ki67 was significant increased and an increase, but not significant, was detected for pSMAd2 in eutopic and ectopic endometrium compared to control one.  In summary, the significant direct correlation between TGFb1 and pSmad2 as well as between HtrA1 and TGFb1 and the very significant increase of Ki67 in stromal compartment of eutopic endometrium suggest a possible involvement of HtrA1 in the pathogenesis of endometriosis.

The trimeric serine protease HtrA1 forms a cage-like inhibition complex with an anti-HtrA1 antibody

High temperature requirement A1 (HtrA1) is a trypsin-fold serine protease implicated in the progression of age-related macular degeneration (AMD). Our interest in an antibody therapy to neutralize HtrA1 faces the complication that the target adopts a trimeric arrangement, with three active sites in close proximity. In the present study, we describe antibody 94, obtained from a human antibody phage display library, which forms a distinct macromolecular complex with HtrA1 and inhibits the enzymatic activity of recombinant and native HtrA1 forms. Using biochemical methods and negative-staining EM we were able to elucidate the molecular composition of the IgG94 and Fab94 complexes and the associated inhibition mechanism. The 246-kDa complex between the HtrA1 catalytic domain trimer (HtrA1_Cat) and Fab94 had a propeller-like organization with one Fab bound peripherally to each protomer. Low-resolution EM structures and epitope mapping indicated that the antibody binds to the surface-exposed loops B and C of the catalytic domain, suggesting an allosteric inhibition mechanism. The HtrA1_Cat-IgG94 complex (636 kDa) is a cage-like structure with three centrally located IgG94 molecules co-ordinating two HtrA1_Cat trimers and the six active sites pointing into the cavity of the cage. In both complexes, all antigen-recognition regions (paratopes) are found to bind one HtrA1 protomer and all protomers are bound by a paratope, consistent with the complete inhibition of enzyme activity. Therefore, in addition to its potential therapeutic usefulness, antibody 94 establishes a new paradigm of multimeric serine protease inhibition.

Association of familial macular degeneration with specific genetic markers: a case report

INTRODUCTION

Age-related macular degeneration is a serious visual disorder of the central retina and was recently reported to be associated with genetic background. Here we describe a genetic link to early onset age-related macular degeneration in members of an Asian family.

CASE PRESENTATION

A 73-year-old Asian woman developed age-related macular degeneration in the fifth decade of her life and her 49-year-old daughter developed age-related macular degeneration. Because of the family history and the early onset, family members were tested for two single nucleotide polymorphism variants (rs10490924 and rs11200638) at a recently identified susceptibility locus for age-related macular degeneration. Both alleles in the 73-year-old woman were of the high-risk variants (T/T for rs10490924 and A/A for rs11200638), and her two daughters and a grandson each carried the risk variants (T and A) one on each allele.

CONCLUSIONS

In a case where multiple family members had early onset age-related macular degeneration, we found two high-risk single nucleotide polymorphism variants in the age-related macular degeneration susceptibility locus, suggesting the combination of the known single nucleotide polymorphism variants as a potent age-related macular degeneration diagnostic indicator.

HtrA1 regulates epithelial-mesenchymal transition in hepatocellular carcinoma

BACKGROUND AND AIMS

Epithelial-mesenchymal transition (EMT) is involved in the development and progression of cancer. HtrA1 had been showed to play a modulatory role in metastasis of hepatocellular carcinoma (HCC). The relationship between HtrA1 and EMT in HCC was investigated in the present study.

METHODS

The HtrA1 expression in human HCC tumor tissues and cells was determined by real-time PCR. SiRNA-HtrA1 and pcDNA-HtrA1 were respectively transfected into HepG2 and MHCC97H cells to observe their effects on cell migration and expression of EMT-associated markers Vimentin and E-cadherin. The relationship between HtrA1 and EMT in 60 HCC patients was also investigated.

RESULTS

HtrA1 expression of tumor tissues was down-regulated with the increasing of number in lymph nodes metastasis in HCC patients. HtrA1 down-regulation led to the significant increase of cell migration, Vimentin expression and decrease of E-cadherin expression, while HtrA1 overexpression resulted in an opposite function. The HtrA1 expression was positively related to the E-cadherin level (R(2) = 0.5903, P < 0.001) and negatively correlated with Vimentin level (R(2) = 0.6067, P < 0.001) in tumor tissues of HCC, respectively.

CONCLUSION

HtrA1 expression was closely related to EMT, which might be a potential mechanism underlying metastasis of HCC.

Synonymous variants in HTRA1 implicated in AMD susceptibility impair its capacity to regulate TGF-β signaling

High-temperature requirement A1 (HTRA1) is a secreted serine protease reported to play a role in the development of several cancers and neurodegenerative diseases. Still, the mechanism underlying the disease processes largely remains undetermined. In age-related macular degeneration (AMD), a common cause of vision impairment and blindness in industrialized societies, two synonymous polymorphisms (rs1049331:C>T, and rs2293870:G>T) in exon 1 of the HTRA1 gene were associated with a high risk to develop disease. Here, we show that the two polymorphisms result in a protein with altered thermophoretic properties upon heat-induced unfolding, trypsin accessibility and secretion behavior, suggesting unique structural features of the AMD-risk-associated HTRA1 protein. Applying MicroScale Thermophoresis and protease digestion analysis, we demonstrate direct binding and proteolysis of transforming growth factor β1 (TGF-β1) by normal HTRA1 but not the AMD-risk-associated isoform. As a consequence, both HTRA1 isoforms strongly differed in their ability to control TGF-β mediated signaling, as revealed by reporter assays targeting the TGF-β1-induced serpin peptidase inhibitor (SERPINE1, alias PAI-1) promoter. In addition, structurally altered HTRA1 led to an impaired autocrine TGF-β signaling in microglia, as measured by a strong down-regulation of downstream effectors of the TGF-β cascade such as phosphorylated SMAD2 and PAI-1 expression. Taken together, our findings demonstrate the effects of two synonymous HTRA1 variants on protein structure and protein interaction with TGF-β1. As a consequence, this leads to an impairment of TGF-β signaling and microglial regulation. Functional implications of the altered properties on AMD pathogenesis remain to be clarified.

MMP20 and ARMS2/HTRA1 Are Associated with Neovascular Lesion Size in Age-Related Macular Degeneration

PURPOSE

Age-related macular degeneration (AMD) is the leading cause of severe visual impairment. Despite treatment, a central scotoma often remains. The size of the scotoma depends on the lesion size of the choroidal neovascular membrane and significantly affects the patient's quality of life, and the lesion size of neovascularization also affects response to treatments. The aim of this study was to identify genes associated with the neovascular lesion size in neovascular AMD.

DESIGN

A genome-wide association study (GWAS).

PARTICIPANTS

We included 1146 Japanese patients with neovascular AMD.

METHODS

We performed a 2-stage GWAS for the lesion size of AMD as a quantitative trait among 1146 (first stage: 727, second stage: 419) Japanese patients with neovascular AMD. Lesion size was determined by the greatest linear dimension measured with fluorescein angiography examination before treatment. We examined the association between the genotypic distribution of each single nucleotide polymorphism (SNP) and the trait using an additive model adjusted for age and sex. To evaluate the associations between AMD development and SNPs associated with lesion size, we also performed a case-control study by using the genotype data from these 1146 Japanese patients as case subjects and the fixed dataset from the Nagahama Study as control subjects.

MAIN OUTCOME MEASURES

Genes associated with the lesion size in neovascular AMD.

RESULTS

In the discovery stage, rs10895322 in MMP20 showed a genome-wide significant P value of 6.95×10(-8), and rs2284665 in ARMS2/HTRA1 showed a P value of 1.55×10(-7). The associations of these 2 SNPs were successfully replicated in the replication stage, and a meta-analysis of both stages showed genome-wide significant P values (2.80×10(-9) and 4.41×10(-9), respectively). In a case-control study using 3248 Japanese subjects as controls, we could not find contribution of MMP20 rs10895322 for AMD development. Although MMP20 has been thought to be expressed only in dental tissues, we confirmed MMP20 expression in the human retina and retinal pigment epithelium/choroid with polymerase chain reaction.

CONCLUSIONS

The growth of choroidal neovascularization in AMD would be affected by 2 genes: MMP20, a newly confirmed gene expressed in the retina, and ARMS2/HTRA1, a well-known susceptibility gene for AMD.

Determinants of amyloid fibril degradation by the PDZ protease HTRA1

Excessive aggregation of proteins has a major impact on cell fate and is a hallmark of amyloid diseases in humans. To resolve insoluble deposits and to maintain protein homeostasis, all cells use dedicated protein disaggregation, protein folding and protein degradation factors. Despite intense recent research, the underlying mechanisms controlling this key metabolic event are not well understood. Here, we analyzed how a single factor, the highly conserved serine protease HTRA1, degrades amyloid fibrils in an ATP-independent manner. This PDZ protease solubilizes protein fibrils and disintegrates the fibrillar core structure, allowing productive interaction of aggregated polypeptides with the active site for rapid degradation. The aggregate burden in a cellular model of cytoplasmic tau aggregation is thus reduced. Mechanistic aspects of ATP-independent proteolysis and its implications in amyloid diseases are discussed.