Cysteine Protease Research Articles

Fungal evasion of Drosophila immunity involves blocking the cathepsin-mediated cleavage maturation of the danger-sensing protease

Entomopathogenic fungi play a critical role in regulating insect populations, and representative species from the Metarhizium and Beauveria genera have been developed as eco-friendly biocontrol agents for managing agricultural insect pests. Relative to the advances in understanding antifungal immune responses in Drosophila, knowledge of how fungi evade insect immune defenses remains limited. In this study, we report the identification and characterization of a virulence-required effector Fkp1 in Metarhizium robertsii. Library screening and protein pull-down analysis unveiled that Fkp1 targets the cathepsin protease CtsK1 to inhibit its cleavage maturation of the danger-sensing serine protease Persephone (Psh), thereby facilitating fungal evasion of the Drosophila immune defenses. The Fkp1-like gene is also required in Beauveria bassiana for insect infection. Transgenic expression of Fkp1 in Drosophila suppressed hemolymph cysteine protease activity and down-regulated the expression of antifungal genes. Fkp1 can also mask the Psh cleavage site without interfering with its ability to bait fungal subtilisin proteases. Given the evident compensatory relationship, our data indicate that the protease cascade is more crucial than the molecular pattern pathway in defending flies against fungal infections. This work reveals that Metarhizium fungi have evolved distinct effectors to block the dual recognition pathways of flies for immune evasion and sheds lights on the effector mechanisms mediating microbe-animal interactions.

Dual Inhibitors of SARS-CoV-2 3CL Protease and Human Cathepsin L Containing Glutamine Isosteres Are Anti-CoV-2 Agents.

SARS-CoV-2 3CL protease (Main protease) and human cathepsin L are proteases that play unique roles in the infection of human cells by SARS-CoV-2, the causative agent of COVID-19. Both proteases recognize leucine and other hydrophobic amino acids at the P2 position of a peptidomimetic inhibitor. At the P1 position, cathepsin L accepts many amino acid side chains, with a partial preference for phenylalanine, while 3CL-PR protease has a stringent specificity for glutamine or glutamine analogues. We have designed, synthesized, and evaluated peptidomimetic aldehyde dual-target (dual-acting) inhibitors using two peptide scaffolds based on those of two Pfizer 3CL-PR inhibitors, Nirmatrelvir, and PF-835321. Our inhibitors contain glutamine isosteres at the P1 position, including 2-pyridon-3-yl-alanine, 3-pyridinyl-alanine, and 1,3-oxazo-4-yl-alanine groups. Inhibition constants for these new inhibitors ranged from Ki = 0.6-18 nM (cathepsin L) and Ki = 2.6-124 nM (3CL-PR), for which inhibitors with the 2-pyridon-3-yl-alanal substituent were the most potent for 3CL-PR. The anti-CoV-2 activity of these inhibitors ranged from EC50 = 0.47-15 μM. X-ray structures of the peptidomimetic aldehyde inhibitors of 3CL-PR with similar scaffolds all demonstrated the formation of thiohemiacetals with Cys145, and hydrogen-bonding interactions with the heteroatoms of the pyridon-3-yl-alanyl group, as well as the nitrogen of the N-terminal indole and its appended carbonyl group at the P3 position. The absence of these hydrogen bonds for the inhibitors containing the 3-pyridinyl-alanyl and 1,3-oxazo-4-yl-alanyl groups was reflected in the less potent inhibition of the inhibitors with 3CL-PR. In summary, our studies demonstrate the value of a second generation of cysteine protease inhibitors that comprise a single agent that acts on both human cathepsin L and SARS-CoV-2 3CL protease. Such dual-target inhibitors will provide anti-COVID-19 drugs that remain active despite the development of resistance due to mutation of the viral protease. Such dual-target inhibitors are more likely to remain useful therapeutics despite the emergence of inactivating mutations in the viral protease because the human cathepsin L will not develop resistance. This particular dual-target approach is innovative since one of the targets is viral (3CL-PR) required for viral protein maturation and the other is human (hCatL) which enables viral infection.

Protein Phosphatase 2A B'α and B'β promote pollen wall construction partially through BZR1-activated CEP1 in Arabidopsis.

A well-constructed pollen wall is essential for pollen fertility, which relies on the contribution of tapetum. Our results demonstrate an essential role of the tapetum-expressed protein phosphatase 2A (PP2A) B'α and B'β in pollen wall formation. The b'aβ double mutant pollen grains harbored sticky remnants and tectum breakages, resulting in failed release. B'α and B'β function partially through dephosphorylating and activating BZR1. The bzr1 bes1 double and higher-order mutants of this family displayed similar defects in pollen wall, while bzr1-1D, having an active mBZR1 exhibited fertile pollen grains in a B'α and B'β dependent manner. Correspondingly, the level of phospho-BZR1 is increased and dephospho-BZR1 is decreased in b'aβ and bzr1-1D/b'aβ at anther stages 8-9 as compared with Col-0 and bzr1-1D, respectively. A cysteine protease gene CEP1 was identified as a BZR1 target, whose transcriptional activation necessitates BRREs in the promoter region and BZR1 DNA binding domain. The mRNA level of CEP1 at stages 8-9 was extremely low in bzr1 and bzr1 bes1, while higher in Col-0 and bzr1-1D depending on B'α and B'β. Furthermore, cep1 mutants displayed similar defects in pollen wall. In brief, this study uncovered a PP2A-BZR1-CEP1 regulatory module, providing a new insight into pollen maturation mechanism.

Various Options for Covalent Immobilization of Cysteine Proteases—Ficin, Papain, Bromelain

Various Options for Covalent Immobilization of Cysteine Proteases—Ficin, Papain, Bromelain

Activation and Reactivity of the Deubiquitinylase OTU Cezanne-2 from MD Simulations and QM/MM Calculations.

Cezanne-2 (Cez2) is a deubiquitinylating (DUB) enzyme involved in the regulation of ubiquitin-driven cellular signaling and selectively targets Lys11-linked polyubiquitin chains. As a representative member of the ovarian tumor (OTU) subfamily DUBs, it performs cysteine proteolytic isopeptide bond cleavage; however, its exact catalytic mechanism is not yet resolved. In this work, we used different computational approaches to get molecular insights into the Cezanne-2 catalytic mechanism. Extensive molecular dynamics (MD) simulations were performed for 12 μs to model free Cez2 and the diubiquitin (diUb) substrate-bound protein-protein complex in two different charge states of Cez2, each corresponding to a distinct reactive state in its catalytic cycle. The simulations were analyzed in terms of the relevant structural parameters for productive enzymatic catalysis. Reactive diUb-Cez2 complex configurations were identified, which lead to isopeptide bond cleavage and stabilization of the tetrahedral oxyanion intermediate. The reliability of these complexes was further assessed by quantum mechanics/molecular mechanics (QM/MM) optimizations. The results show that Cez2 follows a modified cysteine protease mechanism involving a catalytic Cys210/His367 dyad, with the oxyanion hole to be a part of the "C-loop," and polarization of His367 by the formation of a strictly conserved water bridge with Glu173. The third residue has a dual role in catalysis as it mediates substrate binding and polarization of the catalytic dyad. A similar mechanism was identified for Cezanne-1, the paralogue of Cez2. In general, our simulations provide valuable molecular information that may help in the rational design of selective inhibitors of Cez2 and closely related enzymes.

Insights into the catalytic mechanism of archaeal peptidoglycan endoisopeptidases from methanogenic phages.

Archaeal peptidoglycan, a crucial component of the cell walls of Methanobacteria and Methanopyri, enhances the tightness of methanogenic cells and their resistance to known lytic enzymes and antibiotics. Although archaeal peptidoglycan endoisopeptidases (Pei) can reportedly degrade archaeal peptidoglycan, their biochemistry is still largely unknown. In this study, we investigated the activity and catalytic properties of the endoisopeptidases PeiW and PeiP using synthesized isopeptides identical to natural substrates. Enzymatic assays demonstrated their distinct substrate specificity and cleavage efficiency. The crystal structure of Pei revealed a catalytic mechanism resembling that of cysteine peptidases that use the 'CHD' triad to cleave isopeptide bonds. We also identified several key residues in the substrate binding site that confer recognition specificity, including Y174, V252 and C265. Based on the residues present in the active site and their influence on activity, we propose a classification of the archaeal peptidoglycan endoisopeptide family into four categories to facilitate the identification of new archaeal peptidases in the future. These insights into the structure and function of Pei suggest new strategies for use in methanogen biotechnology.

Targeting pleuro-alveolar junctions reverses lung fibrosis in mice

Lung fibrosis development utilizes alveolar macrophages, with mechanisms that are incompletely understood. Here, we fate map connective tissue during mouse lung fibrosis and observe disassembly and transfer of connective tissue macromolecules from pleuro-alveolar junctions (PAJs) into deep lung tissue, to activate fibroblasts and fibrosis. Disassembly and transfer of PAJ macromolecules into deep lung tissue occurs by alveolar macrophages, activating cysteine-type proteolysis on pleural mesothelium. The PAJ niche and the disassembly cascade is active in patient lung biopsies, persists in chronic fibrosis models, and wanes down in acute fibrosis models. Pleural-specific viral therapeutic carrying the cysteine protease inhibitor Cystatin A shuts down PAJ disassembly, reverses fibrosis and regenerates chronic fibrotic lungs. Targeting PAJ disassembly by targeting the pleura may provide a unique therapeutic avenue to treat lung fibrotic diseases.

Papain-Like Cysteine Proteases Contribute to Functional Cleavage of Begomoviral V2 Effector Required for Relevant Virulences.

The begomoviral V2 protein is known to be multifunctional, including its interaction with and inhibition of CYP1, a papain-like cysteine protease (PLCP). However, the effect of this interaction on viral pathogenicity remains unclear. Cotton leaf curl Multan virus (CLCuMuV), a typical monopartite begomovirus associated with a betasatellite, is one of the main pathogens responsible for cotton leaf curl disease. This study verifies the interaction between CLCuMuV V2 and NbCP15, a PLCP homologue in Nicotiana benthamiana. The results show that V2 can be cleaved by NbCP15 invitro, with the N-terminal cleavage site located between the second and third amino acids. Using an Agrobacterium-mediated inoculation method, we investigated the influence of cleavage sites on viral pathogenicity. The findings indicate that mutation of the third amino acid in V2 (V2D3A) reduced the pathogenicity of both heterologous PVX and CLCuMuV. Additionally, the NbCP15 gene mutation in N. benthamiana (nbcp15) also resulted in reduced CLCuMuV pathogenicity. These results suggest that CLCuMuV V2 may promote viral infection through its interaction with plant PLCPs.

Cys44 of SARS-CoV-2 3CLpro affects its catalytic activity.

SARS-CoV-2 encodes a 3C-like protease (3CLpro) that is essential for viral replication. This cysteine protease cleaves viral polyproteins to release functional nonstructural proteins, making it a prime target for antiviral drug development. We investigated the inhibitory effects of halicin, a known c-Jun N-terminal kinase inhibitor, on 3CLpro. Mass spectrometry and crystallographic analysis revealed that halicin covalently binds to several cysteine residues in 3CLpro. As expected, Cys145, the catalytic residue, was found to be the most targeted residue by halicin. Secondly, Cys44 was found to be modified, suggesting a potential inhibitory role of this residue. A mutant protease (Cys44Ala) was generated to further understand the function of Cys44. In silico and enzymatic assays showed that the mutation significantly reduced the stability and activity of 3CLpro, indicating the importance of Cys44 in maintaining the active conformation of the protease. Differential scanning fluorimetry assays confirmed this evidence, showing a reduced thermal stability of the mutant compared to the wild-type protease. Our results highlight the potential of halicin as a multi-target inhibitor of 3CLpro and underline the importance of Cys44 in the function of the protease. These findings contribute to the development of effective antiviral therapies against COVID-19 by targeting critical residues in 3CLpro.

Tick salivary cystatin Iristatin limits the virus replication in skin of tick-borne encephalitis virus–infected mice

Tick-borne encephalitis virus (TBEV) is flavivirus transmitted to the host via tick saliva which contains various molecules with biological impacts. One of such molecules is Iristatin, a cysteine protease inhibitor from Ixodes ricinus that has been shown to have immunomodulatory properties. To characterize Iristatin in the relation to TBEV, we investigate whether this tick inhibitor has any capacity to influence TBEV infection. Mice were intradermally infected by TBEV with or without Iristatin and the viral multiplication was determined in skin and brain tissues by RT-PCR two and 5 days after infection. The viral RNA was detected in both intervals in skin and increased by time. The application of Iristatin caused a reduction in viral RNA in skin but not in the brain of infected mice 5 days post-infection. Moreover, anti-viral effect of Iristatin on skin was accompanied by a significant decline of interferon-stimulated gene 15 gene expression. The effect of Iristatin on TBEV replication was tested also in vitro in primary macrophages and dendritic cells; however, no changes were observed suggesting no direct interference of Iristatin with virus replication. Still, the Iristatin caused a suppression of Erk1/2 phosphorylation in TBEV-infected dendritic cells and had the anti-apoptotic effect. This is the first report showing that a tick cystatin decreases the viral RNA in the host skin, likely indirectly through creating skin environment that is less supportive for TBEV replication. Assuming, that viral RNA reflects the amount of infectious virus, decline of TBEV in host skin could influence the tick biology or virus transmission during cofeeding.

INDICATORS OF APOPTOTIC ACTIVITY IN PATIENTS WITH COMBINED STAGE II ESSENTIAL HYPERTENSION AND STAGE II-III CHRONIC OBSTRUCTIVE PULMONARY DISEASE BASED ON COMORBIDITY CLINICAL FEATURES

The purpose of the study is to improve the diagnosis, prognosis and treatment of chronic obstructive pulmonary disease stage II-III in combination with essential hypertension stage II based on the study of the clinical and pathogenetic role of apoptosis markers. Introduction. Chronic obstructive pulmonary disease (COPD) is a progressive, chronic condition characterized by recurrent exacerbations that are the primary reason for COPD patients to seek medical care, accounting for hospitalizations and contributing to mortality rates. Frequent exacerbations are associated with reduced quality of life and poorer prognoses. Each episode accelerates the progression of COPD, exacerbating respiratory failure and complicating its management. Severe exacerbations pose a significant threat to life and are a leading cause of fatal outcomes. Essential hypertension (EH), often observed in the course of COPD, depends on the severity of the pulmonary pathology and bronchial tree obstruction. In such cases, it is termed pulmonogenic hypertension, occurring in 18–30% of cases. Conversely, COPD may develop under pre-existing hypertensive disease or symptomatic arterial hypertension. The interplay of these conditions substantially influences their clinical course and outcomes. The study aims to enhance the diagnosis, prognosis, and treatment of stage II–III COPD combined with stage II essential hypertension by investigating the clinical and pathogenetic role of apoptosis markers. Materials and methods. The results of the study are based on the data of a comprehensive examination and dynamic observation of 121 patients of both sexes, aged from 30 to 67 years, who were examined over the period 2016-2018 years and underwent inpatient treatment at the Zaporizhzhya Regional Clinical Hospital. The patients were divided into 3 groups, comparable by age and sex: the main group included 40 patients with chronic obstructive pulmonary disease stage II-III (moderately severe course) in combination with essential hypertension stage II of various cardiovascular risk (average age 50.81±0.99 years); the 1st comparison group included 48 patients with chronic obstructive pulmonary disease stage II-III (average age 50.7±1.53 years); the 2nd comparison group consisted of 33 patients with essential hypertension stage II of various cardiovascular risk (average age 51.68±1.22 years). To determine the reference values ​​of the studied indicators, 20 healthy people were examined as a control group. Results. The analysis of the dynamics of cysteine proteases revealed a statistically significant increase in these apoptosis markers in patients with comorbid chronic obstructive pulmonary disease (COPD) and essential hypertension (EH). This elevation was associated with advancing age, longer disease duration, and greater severity of both COPD and EH. Regression analysis indicated a strong relationship between blood caspase-7 levels and future exacerbation risks, as measured by the SAT score. The relationship is best described by a quadratic regression model, with the following parameters: R = 0.73, R² = 0.53, normalized R² = 0.51, F = 39.56, p < 0.001. Conclusion. Apoptotic processes play a significant role in the development of exacerbations in the comorbid course of chronic obstructive pulmonary disease and essential hypertension.

Cysteine Peptidases of Calotropis procera (Apocynaceae): A Literature Review on their Biochemical Properties and Potential Applications.

The latex of the xerophytic plant Calotropis procera, popularly known as giant milkweed, contains a complex mixture of secondary metabolites and proteins and has attracted the attention of many researchers. Several bioactive laticifer enzymes from C. procera have been studied for their potential applications in the medical, agricultural and food industries. The present work aimed to review the current scientific knowledge on cysteine peptidases from the latex of this plant, highlighting their biochemical properties and possible uses as biotechnological tools. Bibliographic databases (PubMed, Scopus and Web of Science) were searched for scientific works published in the last six decades reporting the purification, biochemical characterization, molecular cloning and potential applications of laticifer cysteine peptidases from C. procera. Since the first works published in the late 1960s on the occurrence of thiol peptidases in this species, five cysteine peptidases (procerain, procerain B, CpCP-1, CpCP-2 and CpCP-3) have been purified and biochemically characterized. The characterized enzymes are members of the subfamily C1A of sulfhydryl proteases, showing the characteristic biochemical and structural features of papain and related proteins. Several biological activities of the purified enzymes have been demonstrated, including the inhibition of phytopathogenic fungi and milk coagulation properties, which may be of practical use. Moreover, pharmacologically active propeptides released from the posttranslational processing of C. procera cysteine peptidase zymogens have been shown to be promising therapeutic agents against cancer cells. Further research is needed to provide a better comprehensive understanding of the mode of action and biosafety of these molecules.

Discovery of a Potent Triazole-Based Reversible Targeted Covalent Inhibitor of Cruzipain.

Cruzipain (CZP) is an essential cysteine protease of Trypanosoma cruzi, the etiological agent of Chagas disease, and a promising druggable target. To date, no CZP inhibitors have reached clinical use, with research efforts mostly hampered by insufficient potency, limited target selectivity or lack of bioactivity translation from the isolated enzyme to the parasite in cellular environments. In this study, we report the design of SH-1, a 1,2,3-triazole-based targeted covalent inhibitor with nanomolar potency (IC50 = 28 nM) and null inhibition of human cathepsin L. SH-1 demonstrates bioactivity translation comparable to that of K777 (1-10 μM), a CZP inhibitor previously advanced to clinical trials. Experimental findings indicate that SH-1 forms a reversible covalent bond with Cys25 in CZP, while in silico and structure-activity relationship studies suggest that this interaction is guided by acid-base equilibrium dynamics. The potential of SH-1 for preclinical development is discussed alongside detailed structure-activity relationships for the further optimization of CZP inhibitors.

TFAP2A Promotes Cell Progression and Suppresses Ferroptosis in Lung Adenocarcinoma via Activating Transcription of CST1.

Lung adenocarcinoma (LUAD) is a common type of lung cancer with complicated pathological mechanism. Transcription Factor AP-2 Alpha (TFAP2A) and Cysteine protease inhibitor 1 (CST1) are upregulated genes in LUAD samples, accordingly, we focused on clarifying the role of TFAP2A/CST1 axis in LUAD. Expression analysis was performed using real-time quantitative polymerase chain reaction and western blot. Cellular behaviors were detected by colony formation assay, EdU assay, wound healing assay and flow cytometry. Ferroptosis was assessed by oxidative indicators, Fe2+ level and related proteins. TFAP2A and CST1 interaction was analyzed via ChIP assay and dual-luciferase reporter assay. TFAP2A function in vivo was evaluated by xenograft tumor assay. CST1 was overexpressed in LUAD samples and cells. Downregulation of CST1 inhibited proliferation, migration but it promoted apoptosis and ferroptosis of LUAD cells. TFAP2A interacted with the promoter of CST1 to up-regulate CST1 expression. TFAP2A regulated the malignant behaviors and ferroptosis of LUAD cells by targeting CST1. TFAP2A affected LUAD tumor growth via mediating CST1. All these data proved that TFAP2A/CST1 axis contributed to proliferation, migration while it suppressed apoptosis and ferroptosis in LUAD.

USP39 regulates pyruvate handling in non-small cell lung cancer

The ubiquitin-specific peptidase 39 (USP39) belongs to the USP family of cysteine proteases representing the largest group of human deubiquitinases (DUBs). While the oncogenic function of USP39 has been investigated in various cancer types, its roles in non-small cell lung cancer (NSCLC) remain largely unknown. Here, by applying a gene set enrichment analysis (GSEA) on lung adenocarcinoma tissues and metabolite set enrichment analysis (MSEA) on NSCLC cells depleted of USP39, we identified a previously unknown link between USP39 and the metabolism in NSCLC cells. Mechanistically, we uncovered a component of the pyruvate dehydrogenase (PDH) complex, pyruvate dehydrogenase E1 subunit alpha (PDHA), as a target of USP39. We further present that USP39 silencing caused an elevation in Lys63 ubiquitination on PDHA and a reduction in the PDH complex activity, the levels of TCA cycle intermediates, mitochondrial respiration, cell proliferation in vitro, and of tumor growth in vivo. Consistently, citrate supplementation restored mitochondrial respiration and cell growth in USP39-depleted cells. Our study elucidates and describes how USP39 regulates pyruvate metabolism through a deubiquitylation process that affects NSCLC tumor growth.

Single-dose tolerability and pharmacokinetics of leritrelvir in Chinese patients with hepatic impairment and healthy matched controls.

This study evaluated the safety and pharmacokinetics (PK) of a single dose of leritrelvir, a novel inhibitor of 3-chymotrypsin-like cysteine protease (3CLpro), in patients with hepatic impairment versus healthy participants with normal hepatic function. Eight participants with mild (Child-Pugh A) hepatic impairment, eight with moderate (Child-Pugh B) hepatic impairment, and eight healthy matched control participants were enrolled in this open-label, parallel clinical trial. After administration of leritrelvir of 400 mg, PK parameters were calculated and compared across groups. In total, 24 participants were enrolled and completed the study. Leritrelvir was generally well tolerated, with no serious adverse events or deaths reported during the study. Compared to the group with normal hepatic function, the geometric least-squares mean ratios (90% confidence intervals) for Cmax, AUC0-t, and AUC0-∞ of leritrelvir in participants with mild hepatic impairment were 96.9% (69.3%, 135%), 92.2% (69.6%, 122%), and 92.1% (69.7%, 122%), respectively. For moderate hepatic impairment, the corresponding ratios were 91.6% (61.7%, 136%), 113% (80.0%, 160%), and 113% (80.0%, 159%). Leritrelvir exposures were comparable among the three groups. Overall, there was no clinically relevant difference in leritrelvir exposure in participants with hepatic impairment compared to normal controls. No dose adjustment is required for leritrelvir in patients with mild or moderate hepatic impairment.CLINICAL TRIALSThis study is registered with ClinicalTrials.gov as NCT06161259.

Characterization of a novel covS SNP identified in Australian group A Streptococcus isolates derived from the M1UK lineage.

Group A Streptococcus (GAS) is a human-adapted pathogen responsible for a variety of diseases. The GAS M1UK lineage has contributed significantly to the recently reported increases in scarlet fever and invasive infections. However, the basis for its evolutionary success is not yet fully understood. During the transition to systemic disease, the M1 serotype is known to give rise to spontaneous mutations in the control of virulence two-component regulatory system (CovRS) that confer a fitness advantage during invasive infections. Mutations that inactivate CovS function result in the de-repression of key GAS virulence factors such as streptolysin O (SLO), a pore-forming toxin and major trigger of inflammasome/interleukin-1β-dependent inflammation. Conversely, expression of the streptococcal cysteine protease SpeB, which is required during initial stages of colonization and onset of invasive disease, is typically lost in such mutants. In this study, we identified and characterized a novel covS single nucleotide polymorphism detected in three separate invasive M1UK isolates. The resulting CovSAla318Val mutation caused a significant upregulation of SLO resulting in increased inflammasome activation in human THP-1 macrophages, indicating an enhanced inflammatory potential. Surprisingly, SpeB production was unaffected. Site-directed mutagenesis was performed to assess the impact of this mutation on virulence and global gene expression. We found that the CovSAla318Val mutation led to subtle, virulence-specific changes of the CovRS regulon compared to previously characterized covS mutations, highlighting an unappreciated level of complexity in CovRS-dependent gene regulation. Continued longitudinal surveillance is warranted to determine whether this novel covS mutation will expand in the M1UK lineage.IMPORTANCEThe M1UK lineage of GAS has contributed to a recent global upsurge in scarlet fever and invasive infections. Understanding how GAS can become more virulent is critical for infection control and identifying new treatment approaches. The two-component CovRS system, comprising the sensor kinase CovS and transcription factor CovR, is a central regulator of GAS virulence genes. In the M1 serotype, covRS mutations are associated with an invasive phenotype. Such mutations have not been fully characterized in the M1UK lineage. This study identified a novel covS mutation in invasive Australian M1UK isolates that resulted in a more nuanced virulence gene regulation compared to previously characterized covS mutations. A representative isolate displayed upregulated SLO production and triggered amplified interleukin-1β secretion in infected human macrophages, indicating an enhanced inflammatory potential. These findings underscore the need for comprehensive analyses of covRS mutants to fully elucidate their contribution to M1UK virulence and persistence.

Electrochemical and optical methods for detection of cystatin C as a biomarker of kidney disease.

The kidneys have vital functions in the body, including maintaining homeostasis and blood pressure, controlling water-electrolyte balance, and eliminating metabolic wastes. Early identification of renal dysfunction disease and selection of effective treatment methods reduce mortality in patients. Nowadays, Common indicators of kidney function lack the necessary specificity and sensitivity, but recent studies have reported that cystatin C (CysC) may be an ideal marker for glomerular filtration. CysC, known as a cysteine protease inhibitor, is synthesized by nucleated cells and is easily filtered due to its positive charge and low molecular weight. Also, the synthesis and secretion of CysC is a stable process that is not affected by dietary factors, enhanced protein catabolism, and renal conditions. Various studies have reported that measuring the level of CysC in the body's biological fluids is necessary for the treatment and diagnosis of a wide range of diseases, especially chronic kidney disease (CKD).Despite evidence that positive correlation between the high risk and/or progression of CKD and CysC, it's applied in clinical practice is still rare. Biosensors have been widely developed and researched as an effective method for the pharmaceutical, environmental, and medical fields. Biosensors are designed to create an effective electronic signal commensurate with the concentration of a particular biochemical.Recently, many studies have used biosensor techniques to detect CysC in kidneys and other diseases. In this study, we attempt to examine studies that have used different biosensor techniques for the detect CysC.

Detecting Colorectal Neoplasia Using Specific Fecal Fluorogenic Protease-Sensitive Substrates: A Pilot Study.

identification and removal of advanced adenomas (AA) reduce colorectal cancer (CRC) incidence and potentially mortality. CRC screening often uses fecal immunochemical testing to select high-risk individuals for colonoscopy, despite its low sensitivity for AA and relatively high false-positivity rate. Previous studies have linked proteases to CRC development through their ability to facilitate angiogenesis and immunoregulation. This study aims to identify colorectal neoplasia-associated proteases and their substrates as a potential noninvasive screening test, introducing an innovative application of fecal protease profiling, which has previously been limited to tissue samples. eighteen fluorogenic substrates were designed based on literature. Proteolytic degradation of these substrates was measured in fecal samples of patients with CRC (n = 12), AA (n = 9), nonadvanced adenomas (n = 10), and controls (n = 14). Substrate degradation was correlated to a matched human proteome data set, and underlying proteases were identified based on their recognition patterns. Experiments with protease inhibitors and ZnCl2 were performed to further characterize the involved proteases. in total, 7 of the 18 substrates tested showed a significantly decreased proteolytic degradation in feces from patients with any colorectal neoplasia compared to the control group. The l-aspartic acid-l-glutamic acid substrate (ED) showed significantly decreased degradation in AA and CRC patients. ED degradation significantly decreased with the addition of ZnCl2 and the cysteine protease inhibitor NEM. we successfully developed colorectal neoplasia-specific fluorogenic substrates, highlighting the ED substrate as a potential substrate for the detection of AA and CRC. Although the responsible proteases require further identification, our results suggest an association with calcium-dependent cysteine proteases.

Biological evaluation of trans-2,3-dihydrofuro[3,2-c]coumarins as potential cathepsin inhibitors and anticancer agents

Novel trans-2,3-dihydrofuro[3,2-c]coumarins were synthesized and assessed for their inhibition potential against cysteine proteases: cathepsin B, H and L which are the possible targets for anticancer activity. In general, the coumarin derivatives were found to be exceptional inhibitors against this class of enzymes. On the basis of molecular modeling data and structure–activity relationships, their inhibition patterns are also discussed. The selectivity of designed compounds as inhibitors against cathepsins B, H and L was demonstrated by enzyme inhibition data. Enzyme kinetics investigations were also on par with in vitro studies when tested on HepG2 carcinoma cell line utilizing 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide. Possible protein–drug interactions responsible for potential inhibition are demonstrated using docking studies.