The Set of Serine Peptidases of the Tenebrio molitor Beetle: Transcriptomic Analysis on Different Developmental Stages.

Serine peptidases (SPs) of the chymotrypsin S1A subfamily are an extensive group of enzymes found in all animal organisms, including insects. Here, we provide analysis of SPs in the yellow mealworm Tenebrio molitor transcriptomes and genomes datasets and profile their expression patterns at various stages of ontogeny. A total of 269 SPs were identified, including 137 with conserved catalytic triad residues, while 125 others lacking conservation were proposed as non-active serine peptidase homologs (SPHs). Seven deduced sequences exhibit a complex domain organization with two or three peptidase units (domains), predicted both as active or non-active. The largest group of 84 SPs and 102 SPHs had no regulatory domains in the propeptide, and the majority of them were expressed only in the feeding life stages, larvae and adults, presumably playing an important role in digestion. The remaining 53 SPs and 23 SPHs had different regulatory domains, showed constitutive or upregulated expression at eggs or/and pupae stages, participating in regulation of various physiological processes. The majority of polypeptidases were mainly expressed at the pupal and adult stages. The data obtained expand our knowledge on SPs/SPHs and provide the basis for further studies of the functions of proteins from the S1A subfamily in T. molitor.

The monodomain Kunitz protein EgKU-7 from the dog tapeworm Echinococcus granulosus is a high-affinity trypsin inhibitor with two interaction sites.

Typical Kunitz proteins (I2 family of the MEROPS database, Kunitz-A family) are metazoan competitive inhibitors of serine peptidases that form tight complexes of 1:1 stoichiometry, mimicking substrates. The cestode Echinococcus granulosus, the dog tapeworm causing cystic echinococcosis in humans and livestock, encodes an expanded family of monodomain Kunitz proteins, some of which are secreted to the dog host interface. The Kunitz protein EgKU-7 contains, in addition to the Kunitz domain with the anti-peptidase loop comprising a critical arginine, a C-terminal extension of ∼20 amino acids. Kinetic, electrophoretic, and mass spectrometry studies using EgKU-7, a C-terminally truncated variant, and a mutant in which the critical arginine was substituted by alanine, show that EgKU-7 is a tight inhibitor of bovine and canine trypsins with the unusual property of possessing two instead of one site of interaction with the peptidases. One site resides in the anti-peptidase loop and is partially hydrolyzed by bovine but not canine trypsins, suggesting specificity for the target enzymes. The other site is located in the C-terminal extension. This extension can be hydrolyzed in a particular arginine by cationic bovine and canine trypsins but not by anionic canine trypsin. This is the first time to our knowledge that a monodomain Kunitz-A protein is reported to have two interaction sites with its target. Considering that putative orthologs of EgKU-7 are present in other cestodes, our finding unveils a novel piece in the repertoire of peptidase-inhibitor interactions and adds new notes to the evolutionary host-parasite concerto.

SPINT2 is involved in the proliferation, migration and phenotypic switching of aortic smooth muscle cells: Implications for the pathogenesis of thoracic aortic dissection.

Thoracic aortic dissection (TAD) is a severe and extremely dangerous cardiovascular disease. Proliferation, migration and phenotypic switching of vascular smooth muscle cells (SMCs) are major pathogenetic mechanisms involved in the development of TAD. The present study was designed to investigate the expression and potential function of serine peptidase inhibitor Kunitz type 2 (SPINT2) in TAD. The gene expression profile data for ascending aorta from patients with TAD were downloaded from the GEO database with the accession number GSE52093. Bioinformatics analysis using GEO2R indicated that the differentially expressed SPINT2 was prominently decreased in TAD. The expression levels of SPINT2 mRNA and protein in aortic dissection specimens and normal aorta tissues were measured using reverse transcription-quantitative PCR and western blotting. SPINT2 expression was downregulated in clinical samples from aortic dissection specimens of patients with TAD compared with the corresponding expression noted in tissues derived from patients without TAD. In vitro, platelet-derived growth factor BB (PDGF-BB) was applied to induce the isolated primary mouse aortic SMC phenotypic modulation (a significant upregulation in the expression levels of synthetic markers), and the SMCs were infected with the adenoviral vector, Ad-SPINT2, to construct SPINT2-overexpressed cell lines. SMC viability was detected by an MTT assay and SMC proliferation was detected via the presence of Ki-67-positive cells (immunofluorescence staining). To explore the effects of SPINT2 on SMC migration, a wound healing assay was conducted. ELISA and western blotting assays were used to measure the content and expression levels of MMP-2 and MMP-9. The expression levels of vimentin, collagen I, α-SMA and SM22α were measured using western blotting. The PDGF-BB-induced proliferation and migration of SMCs were recovered by SPINT2 overexpression. The increase in the expression levels of SPINT2 reduced the expression levels of active matrix metalloproteinases (MMPs), MMP-2 and MMP-9. Overexpression of SPINT2 suppressed SMC switching from a contractile to a synthetic type, as evidenced by decreased vimentin and collagen I expression levels along with increased α-smooth muscle actin and smooth muscle protein 22-α expression levels. Furthermore, activation of ERK was inhibited in SPINT2-overexpressing SMCs. A specific ERK agonist, 12-O-tetradecanoylphorbol-13-acetate, reversed the SPINT2-mediated inhibition of SMC migration and the phenotypic switching. Collectively, the data indicated that SPINT2 was implicated in the proliferation, migration and phenotypic switching of aortic SMCs, suggesting that it may be involved in TAD progression.

Case report: Heterozygous mutation in HTRA1 causing typical cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy.

Background: Cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL) is an autosomal recessive disorder characterized by baldness, recurrent ischemic stroke, lumbago, headache, and dementia which is closely related to homozygous mutations of the high-temperature requirement serine peptidase A1 (HTRA1) gene. Heterozygous mutations of HTRA1 are usually considered to be non-pathogenic. Although it has been revealed that only a few patients with heterozygous mutations could present some manifestations, their clinical symptoms were atypical, milder, and always with a lower frequency of extra-neurological features. Here, a rare patient with heterozygous mutation of HTRA1 who had all typical features of CARASIL as well as severe clinical symptoms and rapid progression was initially reported in our study. Case presentation: A 43-year-old female patient presented with a gradual onset of headache and cognitive decline. As time progressed, her headache intensified and symptoms of dementia began to manifest gradually. During her early years, she had thinning hair and subsequently experienced two occurrences of ischemic strokes in her thirties. Furthermore, she also had a history of lumbago and urinary retention before visiting our hospital. The patient's magnetic resonance imaging revealed the presence of widespread white matter lesions, infarctions, and microbleeds, in addition to lumbar disc herniation and degenerative lesions. The observed clinical characteristics had a strong correlation with CARASIL, and the patient was diagnosed with a heterozygous missense mutation of 905G>A (Arg302Gln) in the HTRA1 gene. The patient has been under continuous follow-up for a duration exceeding 3 years subsequent to her release from the hospital. She underwent cystostomy, and symptoms of bulbar paralysis developed in a progressive way. Currently, there has been a notable decrease in motor function and activities of daily living, resulting in the individual being confined to bed for a duration exceeding 1 year. Conclusion: This case suggests that patients carrying a heterozygous mutation in G905A may also have typical clinical features of CARASIL, which allows us to have a more comprehensive understanding of CARASIL.

Spatial Distribution and Biochemical Characterization of Serine Peptidase Inhibitors in the Venom of the Brazilian Sea Anemone Anthopleura cascaia Using Mass Spectrometry Imaging.

Sea anemones are known to produce a diverse array of toxins with different cysteine-rich peptide scaffolds in their venoms. The serine peptidase inhibitors, specifically Kunitz inhibitors, are an important toxin family that is believed to function as defensive peptides, as well as prevent proteolysis of other secreted anemone toxins. In this study, we isolated three serine peptidase inhibitors named Anthopleura cascaia peptide inhibitors I, II, and III (ACPI-I, ACPI-II, and ACPI-III) from the venom of the endemic Brazilian sea anemone A. cascaia. The venom was fractionated using RP-HPLC, and the inhibitory activity of these fractions against trypsin was determined and found to range from 59% to 93%. The spatial distribution of the anemone peptides throughout A. cascaia was observed using mass spectrometry imaging. The inhibitory peptides were found to be present in the tentacles, pedal disc, and mesenterial filaments. We suggest that the three inhibitors observed during this study belong to the venom Kunitz toxin family on the basis of their similarity to PI-actitoxin-aeq3a-like and the identification of amino acid residues that correspond to a serine peptidase binding site. Our findings expand our understanding of the diversity of toxins present in sea anemone venom and shed light on their potential role in protecting other venom components from proteolysis.

Upregulation of HTRA1 mediated by the lncRNA NEAT1/miR-141-3p axis contributes to endometriosis development through activating NLRP3 inflammasome-mediated pyroptotic cell death and cellular inflammation.

The present study identified a novel upstream long chain non-coding (lncRNA) NEAT1/miR-141-3p/HTRA1 axis that regulated the activation of NLR family pyrin domain containing 3 (NLRP3) inflammasome to modulate endometriosis (EM) development. Specifically, clinical data suggested that the expression of NLRP3 and apoptosis-associated speck-like protein containing CARD (ASC), the cleavage of caspase-1 and gasdermin D (GSDMD), and the production of inflammatory cytokines (interleukin (IL)-1ß, IL-6, tumor necrosis factor (TNF)-α, and IL-18) were all significantly increased in the ectopic endometrium (EE) tissues, compared to the normal endometrium (NE) tissues. Then, through analyzing the datasets from GEO database (GSE2339, GSE58178, and GSE7305) using the GEO2R bioinformatics tools, we verified that HtrA Serine Peptidase 1 (HTRA1) was especially enriched in the EE tissues compared to the NE tissues. To further confirm the biological functions of HTRA1, HTRA1 was overexpressed or downregulated in primary human endometrial stromal cells (hESCs) isolated from NE tissues or EE tissues, respectively. The results showed that upregulation of HTRA1 activated NLRP3 inflammasome-mediated pyroptotic cell death and cellular inflammation in NE-derived hESCs, whereas silencing of HTRA1 played an opposite role in EE-derived hESCs. In addition, the lncRNA NEAT1/miR-141-3p axis was screened as the upstream regulator of HTRA1. Mechanistically, lncRNA NEAT1 sponged miR-141-3p to positively regulate HTRA1 in a competing endogenous RNA (ceRNA) mechanisms-dependent manner. The recovery experiments in hESCs from NE and EE tissues confirmed that lncRNA NEAT1 overexpression promoted NLRP3 inflammasome-mediated pyroptotic cell death through regulating the miR-141-3p/HTRA1 axis. Taken together, this study firstly uncovered the underlying mechanisms by which a novel lncRNA NEAT1/miR-141-3p/HTRA1-NLRP3 pathway contributed to the development of EM, which provided novel diagnostic and therapeutic biomarkers for this disease.

Exploring the contribution of ARMS2 and HTRA1 genetic risk factors in age-related macular degeneration.

Age-related macular degeneration (AMD) is the leading cause of severe irreversible central vision loss in individuals over 65 years old. Genome-wide association studies (GWASs) have shown that the region at chromosome 10q26, where the age-related maculopathy susceptibility (ARMS2/LOC387715) and HtrA serine peptidase 1 (HTRA1) genes are located, represents one of the strongest associated loci for AMD. However, the underlying biological mechanism of this genetic association has remained elusive. In this article, we extensively review the literature by us and others regarding the ARMS2/HTRA1 risk alleles and their functional significance. We also review the literature regarding the presumed function of the ARMS2 protein and the molecular processes of the HTRA1 protein in AMD pathogenesis in vitro and in vivo, including those of transgenic mice overexpressing HtrA1/HTRA1 which developed Bruch's membrane (BM) damage, choroidal neovascularization (CNV), and polypoidal choroidal vasculopathy (PCV), similar to human AMD patients. The elucidation of the molecular mechanisms of the ARMS2 and HTRA1 susceptibility loci has begun to untangle the complex biological pathways underlying AMD pathophysiology, pointing to new testable paradigms for treatment.

Spatial distribution and biochemical characterization of serine peptidase inhibitors in the venom of the brazilian sea anemone anthopleura cascaia using mass spectrometry imaging

Sea anemones are known to produce a diverse array of toxins with different cysteine-rich peptide scaffolds in their venoms. The serine peptidase inhibitors, specifically Kunitz inhibitors, are an important toxin family that is believed to function as defensive peptides, as well as prevent proteolysis of other secreted anemone toxins. In this study, we isolated three serine peptidase inhibitors named Anthopleura cascaia peptide inhibitors I, II, and III (ACPI-I, ACPI-II, and ACPI-III) from the venom of the endemic Brazilian sea anemone A. cascaia. The venom was fractionated using RP-HPLC, and the inhibitory activity of these fractions against trypsin was determined and found to range from 59% to 93%. The spatial distribution of the anemone peptides throughout A. cascaia was observed using mass spectrometry imaging. The inhibitory peptides were found to be present in the tentacles, pedal disc, and mesenterial filaments. We suggest that the three inhibitors observed during this study belong to the venom Kunitz toxin family on the basis of their similarity to PI-actitoxin-aeq3a-like and the identification of amino acid residues that correspond to a serine peptidase binding site. Our findings expand our understanding of the diversity of toxins present in sea anemone venom and shed light on their potential role in protecting other venom components from proteolysis.

A Clinical and Preclinical Assessment of Clinical Trials for Dry Age-Related Macular Degeneration.

Age-related macular degeneration (AMD) is the leading cause of blindness for the elderly in high-income countries. Although multivitamin antioxidant nutrients can slow the progression of intermediate "dry" or nonneovascular AMD, no treatment can halt or reverse any stage of dry disease. Multiple biologic pathways have been implicated in AMD pathobiology, including the complement pathway. These pathways have been targeted by various approaches in clinical trials. To date, no treatment has reached their prespecified primary end point in 2 phase III trials, a requirement by the US Food and Drug Administration for a new drug approval. Here, we describe perspectives on the failures and possible successes of various clinical trials that will guide further investigation. These perspectives will also discuss clinical trial design issues to consider in future investigations, and how recent insights into AMD pathobiology might both provide additional explanation for trials not reaching the prespecified primary end points and offer direction for identifying prioritized treatment targets.

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.

Crystal structure of a Burkholderia peptidase and modification of the substrate-binding site for enhanced hydrolytic activity toward gluten-derived pro-immunogenic peptides.

Celiac disease (CD) is a human autoimmune disease triggered by toxic gluten peptides. Recently, oral enzyme therapy has been proposed to ameliorate the health condition of CD patients based on the concept of removing pepsin-insensitive gluten-derived pro-immunogenic peptides. A Burkholderia peptidase, Bga1903, with promising gluten-degrading activity was characterized previously. Here, we report the crystal structure of Bga1903, in which the core has a α/ß/α fold featured with a twisted six-stranded parallel ß-sheet sandwiched between two layers of α-helices. The mutations at the substrate-binding pocket that might enhance the peptidase's affinity toward tetrapeptide PQPQ were predicted by FoldX. Accordingly, four single-substitution mutants, G351A, E380L, S386F, and S387L, were created. The specificity constant (kcat/KM) of wild type toward chromogenic peptidyl substrates Z-HPK-pNA, Z-HPQ-pNA, Z-HPL-pNA, and Z-QPQ-pNA are 30.2, 7.9, 3.3, and 0.79 s-1·mM-1, respectively, indicating that the QPQ motif, which frequently occurs in pro-immunogenic peptides, is not favorable. Among the mutants, E380L loses the hydrolytic activity toward Z-HPK-pNA, suggesting a critical role of E380 in preferring a lysine residue at the P1 position. S387L shows a 17-fold increase in the specificity constant toward Z-QPQ-pNA and hydrolyzes the pro-immunogenic peptides more efficiently than the wild-type peptidase.

Serine protease inhibitor Kazal type 1 (SPINK1) promotes proliferation, migration, invasion and radiation resistance in rectal cancer patients receiving concurrent chemoradiotherapy: a potential target for precision medicine.

Serine peptidase inhibitor Kazal type-1 (SPINK1), a trypsin kinase inhibitor, is known to be associated with inflammation and pathogenesis. The aim in this study was to demonstrate the clinicopathological role and progression of SPINK1 in rectal cancer (RC) patients undergoing concurrent chemoradiotherapy (CCRT). Immunohistochemical staining for SPINK1 protein expression in 111 RC cases revealed high SPINK1 expression was significantly associated with perineural invasion and poor CCRT response in pre-CCRT specimens. In addition, multivariable analyses showed that pre-CCRT SPINK1 expression was a significant prognostic marker of both overall and disease-free survival in RC patients receiving pre-operative CCRT; furthermore, in vitro studies demonstrated SPINK1 interacted with EGFR to promote the abilities of proliferation, migration and invasion attenuated by SPINK1 si-RNA via ERK, p38, and JNK pathways. SPINK1 was also found to regulate radio-resistance in CRC cell lines. In conclusion, SPINK1 expression is an independent prognostic marker in patients receiving pre-operative CCRT, and SPINK1 regulates proliferation, migration and invasion via EGFR-downstream ERK, p38 and JNK pathways. The phenotypes of radiosensitivity that could be reversed with attenuation of SPINK1 levels suggest that targeting SPINK1 might offer a strategy for optimal precision medicine.

Serine Protease Inhibitor Kazal Type 1, A Potential Biomarker for the Early Detection, Targeting, and Prediction of Response to Immune Checkpoint Blockade Therapies in Hepatocellular Carcinoma.

Background: We aimed to characterize serine protease inhibitor Kazal type 1 (SPINK1) as a gene signature for the early diagnosis, molecular targeting, and prediction of immune checkpoint blockade (ICB) treatment response of hepatocellular carcinoma (HCC). Methods: The transcriptomics, proteomics, and phenotypic analyses were performed separately or in combination. Results: We obtained the following findings on SPINK1. Firstly, in the transcriptomic training dataset, which included 279 stage I and II tumor samples (out of 1,884 stage I-IV HCC specimens) and 259 normal samples, significantly higher area under curve (AUC) values and increased integrated discrimination improvement (IDI) and net reclassification improvement (NRI) were demonstrated for HCC discrimination in SPINK1-associated models compared with those of alpha-fetoprotein (AFP). The calibration of both SPINK1-related curves fitted significantly better than that of AFP. In the two independent transcriptomic validation datasets, which included 201, 103 stage I-II tumor and 192, 169 paired non-tumor specimens, respectively, the obtained results were consistent with the above-described findings. In the proteomic training dataset, which included 98 stage I and II tumor and 165 normal tissue samples, the analyses also revealed better AUCs and increased IDI and NRI in the aforementioned SPINK1-associated settings. A moderate calibration was shown for both SPINK1-associated models relative to the poor results of AFP. Secondly, in the in vitro and/or in vivo murine models, the wet-lab experiments demonstrated that SPINK1 promoted the proliferation, clonal formation, migration, chemoresistance, anti-apoptosis, tumorigenesis, and metastasis of HCC cells, while the anti-SPINK1 antibody inhibited the growth of the cells, suggesting that SPINK1 has "tumor marker" and "targetable" characteristics in the management of HCC. The Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses revealed that SPINK1 was engaged in immunity-related pathways, including T-cell activation. Thirdly, in the transcriptomic analyses of the 368 HCC specimens from The Cancer Genome Atlas (TCGA) cohort, the high abundance of SPINK1 was positively correlated with the high levels of activated tumor-infiltrating CD4+ and CD8+ T lymphocytes and dendritic and natural killer cells, while there were also positive correlations between SPINK1 and immune checkpoints, including PD-1, LAG-3, TIM-3, TIGIT, HAVCR2, and CTLA-4. The ESTIMATE algorithm calculated positive correlations between SPINK1 and the immune and ESTIMATE scores, suggesting a close correlation between SPINK1 and the immunogenic microenvironment within HCC tissues, which may possibly help in predicting the response of patients to ICB therapy. Conclusions: SPINK1 could be a potential biomarker for the early detection, targeted therapy, and prediction of ICB treatment response in the management of HCC.

SPINK2 is a prognostic biomarker related to immune infiltration in acute myeloid leukemia.

BACKGROUND: Serine peptidase inhibitor Kazal type 2 (SPINK2) has been reported to be involved in certain cancers. We conducted an in-depth investigation on the role and mechanism of SPINK2 in acute myeloid leukemia (AML). METHODS: The relationship between SPINK2 expression and AML clinicopathologic characteristics was determined using The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) database. Concomitantly, we used Kaplan-Meier survival analysis, as well as univariate and multivariate regression analyses to evaluate SPINK2 as a prognostic marker of AML. Additionally, we annotated the enrichment and function of SPINK2 using Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Gene Sets Enrichment Analysis (GSEA). The CIBERSORT algorithm was used to analyze the relationship between SPINK2 expression and immune infiltration. RESULTS: SPINK2 expression was significantly higher in AML patients compared to healthy individuals (P<0.001). The area under receiver operating characteristic curve in the GSE9476 dataset was 0.660, whereas that in the Genotype-Tissue Expression (GTEx) and TCGA datasets was 0.935. In addition, GSEA also showed that several pathways were enriched in the group with high SPINK2 expression, such as PI3K-AKT signaling, PD-L1 expression, and checkpoint pathways. Analysis of immune infiltration showed that SPINK2 expression was correlated with certain immune infiltrating cells. Cox multivariate analysis revealed that the level of SPINK2 was an independent risk factor for the progression of AML (P<0.001). Moreover, age, M1, M5, M6, and CytoRisk-Poor also affected the progression of AML (P<0.05). The C-index of the nomogram in our internal validation was 0.702. CONCLUSION: The high expression of SPINK2 in AML suggests that SPINK2 may play an important role in the immune microenvironment and thus could be a biomarker for diagnosis and prognosis of AML.

Specificity protein 1-induced serine peptidase inhibitor, Kunitz Type 1 antisense RNA1 regulates colorectal cancer cell proliferation, migration, invasion and apoptosis through targeting heparin binding growth factor via sponging microRNA-214.

Previous studies indicated that long noncoding RNA (lncRNA) serine peptidase inhibitor, Kunitz type 1 antisense RNA1 (SPINT1-AS1) could function as an oncogenic gene in various human cancers. However, the regulatory mechanisms of SPINT1-AS1 in the tumorigenesis of colorectal cancer (CRC) remain unclear. It was found that SPINT1-AS1 was upregulated in CRC and contributed to the poor prognosis of CRC patients. Silencing of SPINT1-AS1 inhibited proliferation and metastasis but increased apoptosis of CRC cells. Furthermore, we found that SP1 could activate SPINT1-AS1 by acting as a transcription factor. Meanwhile, we identified miR-214 was negatively regulated by SPINT1-AS1. Furthermore, miR-214 repression restored the suppressive effects on malignant biological behaviors of CRC caused by SPINT1-AS1 silencing. In addition, SPINT1-AS1 mediated HDGF expression through targeting miR-214. Finally, overexpressed heparin-binding growth factor (HDGF) overturned the effects on viability, metastasis, and apoptosis of CRC cells induced by SPINT1-AS1 depletion or miR-214 upregulation. In conclusion, our results demonstrated that SP1-induced SPINT1-AS1 could facilitate CRC progression by inhibiting miR-214 and increasing HDGF expression. These findings might provide a new approach for CRC treatment.

Crystal structure and substrate recognition mechanism of the prolyl endoprotease PEP from Aspergillus niger.

Proteases are enzymes that are not only essential for life but also industrially important. Understanding the substrate recognition mechanisms of proteases is important to enhance the use of proteases. The fungus Aspergillus produces a wide variety of proteases, including PEP, which is a prolyl endoprotease from A. niger. Although PEP exhibits amino acid sequence similarity to the serine peptidase family S28 proteins (PRCP and DPP7) that recognize Pro-X bonds in the terminal regions of peptides, PEP recognizes Pro-X bonds not only in peptides but also in proteins. To reveal the structural basis of the prolyl endoprotease activity of PEP, we determined the structure of PEP by X-ray crystallography at a resolution of 1.75 Å. The PEP structure shows that PEP has a wide-open catalytic pocket compared to its homologs. The characteristic catalytic pocket structure of PEP is predicted to be important for the recognition of protein substrates.

Avaliação preditiva estrutural das serino peptidases de aranhas: as relações evolutivas e de estrutura/função

Serine peptidases (SP) are hydrolases represented in many living organisms, with chymotrypsins and trypsins being the main digestive SPs. Studies of genomes, transcriptomes and proteomes of spiders allow identifying these enzymes in different tissues and/or secretions of these animals and suggest that SPs are involved in poisoning and digestion, two very important processes for the evolutionary success of the group. In order to compare the SPs involved in these processes, in silico analyses of the databases of a total of 38 distinct species of spiders were performed, totaling 1,200 sequences of SPs. Proteomic analyses of Nephilingis cruentata, Stegodyphus mimosarum and Acanthoscurria geniculata show the presence of SPs in poisons (SPV) and digestive process (SPD). In general, the SPVs present a molecular mass in the range between 30 and 37 kDa and pI in the range of 4.65 and 9.79, presenting, in most sequences, only the catalytic domain. Fluid and digestive system SPDs mandatorily present the catalytic domain associated with CUB-LDLa, indicating that CUB-LDL SPcatalytic combination is a signature of the digestive SPs of spiders. These enzymes have a molecular mass of 36 to 140 kDa and pI between 4.4 and 5.6. Other differences found among SPV and SPD are: predicted patterns of glycosilation, cell addressing and structural prediction. Among the different digestive SPs there is a distinction between hydrophobicity, electrostatic potential, and substrate accessibility. Molecular docking also allowed predicting the interaction behavior of SPs with inhibitors that mimic substrates, as Kunitz type inhibitors. Analyses indicate that poison enzymes have greater accessibility of the catalytic triad to the substrate. Phylogenetic analyses show that the different groups of digestive SPs are represented in all studied spider species, keeping CUB-LDLa as a signature. The conservation of the CUB-LDLa domain was also observed in SPs of other Groups of Arachnida such as Scorpionidae, Acari and Opiliones, being even present in Limulus representative of the Chelicerata group. The association of these domains is possibly related to different functionalities of SPs in arachnids maintained throughout the evolutionary process.

As serino peptidases (SP) são hidrolases representadas em muitos organismos vivos, sendo as quimotripsinas e tripsinas as principais SPs digestivas. Estudos de genomas, transcriptomas e proteomas de aranhas permitem identificar essas enzimas em diferentes processos fisiológicos desses animais e sugerem que as SPs estão envolvidas no envenenamento e no processo digestivo, dois processos muito importantes para o sucesso evolutivo do grupo. Com o objetivo de comparar as SPs envolvidas nestes processos foram realizadas análises in silico dos bancos de dados de um total de 38 espécies distintas de aranhas, totalizando 1.200 sequências de SPs. Análises proteômicas de Nephilingis cruentata, Stegodyphus mimosarum e Acanthoscurria geniculata mostram a presença de SPs nos venenos (SPV) e no processo digestivo (SPD). Em geral, as SPVs apresentam uma massa molecular na faixa entre 30 e 37 kDa e pI na faixa de 4,65 e 9,79, apresentando, na maioria das sequências, apenas o domínio catalítico. As SPDs de fluido e sistema digestório apresentam obrigatoriamente o domínio catalítico associado a CUB-LDLa, indicando que a combinação CUB-LDLa-SP catalítico é uma assinatura das SPs digestivas de aranhas. Essas enzimas apresentam uma massa molecular de 36 a 140 kDa e o pI entre 4,4 e 5,6. Outras diferenças encontradas são: os padrões preditos de glicosilação, endereçamento celular e predição estrutural. Entre as diferentes SPs digestivas há distinção entre a hidrofobicidade, o potencial eletrostático e a acessibilidade ao substrato. Docking molecular permitiu ainda prever o comportamento de interação das SPs com inibidores que mimetizam substratos como inibidores do tipo Kunitz. As análises indicam que as enzimas de veneno têm maior acessibilidade da tríade catalítica ao substrato. Análises filogenéticas mostram que os diferentes grupos de SPs digestivas estão representados em todos as espécies de aranhas estudadas mantendo CUB-LDLa como assinatura. A conservação do domínio CUB-LDLa também foi observada em SPs de outros grupos de Arachnida como Scorpionidae, Acari e Opiliones, estando inclusive presente em Limulus polyphemus representante do grupo Chelicerata. A associação destes domínios possivelmente está relacionada a diferentes funcionalidades de SPs em aracnídeos mantidas ao longo do processo evolutivo.

Identificação e caracterização bioquímica de inibidores de serinopeptidases isolados a partir da peçonha das anêmonas-do-mar Anthopleura cascaia e Aulactinia veratra

Phylum Cnidaria comprises more than 10,000 species and around 10% of them are represented by sea anemones. These animals are underexplored sources of molecules, possessing structurally diverse toxins that can act over a diverse range of pharmacological targets, including enzymes. Sea anemones represent almost 96% of the manually annotated toxins from the phylum, but until now only 5% of its species have been studied about their toxin content. In the present work, the venoms of the sea anemones Anthopleura cascaia and Aulactinia veratra were studied and accessed through mass spectrometry analysis for searching serine peptidase inhibitors. The arsenal of toxins from both venoms was elucidated. Additionally, venom’s fractions were screened for inhibitory activity over trypsin, using time-course fluorescence-based kinetic assays or Mass spectrometry-based analysis. Beyond that, the spatial distribution of serine peptidase inhibitors in both sea anemones’ tissues were shown through Mass Spectrometry Imaging by MALDITOF. In the analysis of toxins composition, it was seen that A. cascaia venom presents at least three types of toxins: cytolysins, phospholipases and a toxin similar to natterin. For A. veratra, the classification based on blastp hit similarity and relying on domain architecture of the toxin’s sequences (translated transcripts) was performed. The thorough examination over toxins sequences led to the identification of 59 proteins and peptides belonging to 14 known toxin’s families of sea anemones and to the acknowledge of 20 peptides presenting 18 new cysteine scaffolds. The venom of this sea anemone mainly relies on neurotoxins from ShK-like, β-defensins, SCRiP, ICK, EGF-like types and on serine peptidase inhibitors from Kazal and Kunitz types. Furthermore, serine peptidase inhibitors from both venoms were isolated and present main distribution over tentacles, mesenterial filaments and pedal disc of these sea anemones, suggesting the preferential stock of these toxins. In conclusion, the methodological approaches applied in this study were able of identifying the presence of serine peptidase inhibitors on the venom and tissue of sea anemones through chromatographic techniques followed by enzymatic assays, and MALDI-Imaging.

O filo Cnidaria é composto por mais de 10.000 espécies e cerca de 10% destas são anêmonas-do-mar. Estes animais são considerados fontes subexploradas de moléculas, possuindo um diverso arsenal de toxinas que podem agir sobre diferentes alvos farmacológicos, incluindo enzimas. Toxinas de anêmonas-do-mar representam cerca de 96% das toxinas anotadas para o filo Cnidaria, embora apenas 5% de suas espécies tenham sido estudadas quanto à composição de toxinas até o momento. Neste trabalho elucidamos por espectrometria de massas a composição da peçonha das anêmonas Anthopleura cascaia e Aulactinia veratra, buscando a identificação de inibidores de serinopeptidases. O arsenal de toxinas para ambas anêmonas foi elucidado. Ainda, descrevemos as etapas de purificação envolvidas na busca de inibidores e a seleção destes candidatos por meio da inibição da atividade da tripsina, avaliada por duas técnicas distintas։ Cinética enzimática e Espectrometria de massas. Adicionalmente, descrevemos a localização de candidatos a inibidores no tecido das anêmonas através do Imageamento por espectrometria de massas. Na análise sobre a composição de toxinas destas anêmonas, vimos que a peçonha da A. cascaia apresentou a existência três tipos de toxinas incluindo citolisinas, fosfolipases e naterinas. Para a espécie A. veratra, a classificação de toxinas baseadas no blastp hit e na arquitetura de domínios das toxinas foi realizada. Esta análise revelou a presença de 59 proteínas e peptídeos pertencentes a 14 famílias de toxinas de anêmonasdo-mar; além do reconhecimento de 20 peptídeos apresentando 18 novos scaffolds de cisteínas. A peçonha desta anêmona é principalmente composto por neurotoxinas do tipo ShK-like, β-defensinas, SCRiP, ICK, EGF-like e inibidores de serinopeptidases. Os dados obtidos mostram que ambas anêmonas são ricas fontes de inibidores de serinopeptidases, especialmente tipo Kunitz e Kazal. Tais inibidores apresentam distribuição na região dos tentáculos, mesentério e disco pedal das anêmonas, o que pode indicar o estoque preferencial destas toxinas. E conclusão, o conjunto de abordagens metodológicas empregadas neste trabalho foi capaz de atender os objetivos propostos: identificar a presença de inibidores de serinopeptidases na peçonha e tecido de anêmonas, tanto por fracionamento cromatográfico seguido de ensaio enzimático, quanto por MALDI-Imaging.

High-temperature requirement A serine peptidase 1-related cerebral small vessel disease / 中华神经科杂志

The high-temperature requirement A serine peptidase 1 (HTRA1) gene mutation results in cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy and autosomal dominant cerebral small vessel disease (CSVD). This article described the definition, clinical features, magnetic resonance imaging manifestations, genetic and pathological examinations and treatment plans of HTRA1 related CSVD and highlighted the distinction between HTRA1 related CSVD and other inherited disorders with white matter involvement, and proposed a diagnostic pathway for timely recognition of HTRA1 related CSVD in a routine clinical environment. Ultimately, in addition to the conventional treatment of CSVD, effective targeted treatment methods still need to be established.