Cathepsin H: molecular characteristics and clues to function and mechanism

Molecular Profiling of Odontoclasts during Physiological Tooth Replacement

The odontoclast is a rarely studied cell type that is overly active in many dental pathologies, leading to tooth loss. It is difficult to find diphyodont mammals in which either physiological or pathological root resorption can be studied. Here we use the adult leopard gecko, which has repeated cycles of physiological tooth resorption and shedding. RNA-seq was carried out to compare gene expression profiles of functional teeth to developing teeth. Genes more highly expressed in bell-stage developing teeth were related to morphogenesis (PTHLH, SFRP2, SHH, EDAR). Some genes expressed in osteoclasts (ACP5, CTSK, CSF1R) were relatively more abundant in functional teeth compared with developing teeth. There was, however, no differential expression of RANK and RANKL in the 2 tooth types. In addition, functional teeth expressed proteolysis genes not found in osteoclasts (ADAMTS2, 3, 4, 14; CTSA, CTSH, CTSS). We used tartrate acid resistant phosphatase and cathepsin K (CTSK) staining to identify odontoclasts in and around the gecko dentition. There were 3 populations of CTSK cells: (1) large, functional multinucleated odontoclasts in the crown of the tooth with a ruffled border inside resorption pits; (2) smaller, precursor cells in the pulp with fewer nuclei; and (3) flattened external precursor cells next to the root and bone of attachment. We found a positive relationship between developing teeth and the population of CTSK+ cells on the root surface. We tested a candidate signal that may be involved in CTSK+ cell presence. An antagonist of CSF1R was delivered to developing teeth in vivo, which resulted in a significant decrease in CTSK and CSF1R compared with DMSO controls. Thus, the CSF1 signaling pathway is upstream of CTSK in teeth. This is the first work to detail the molecular characteristics of odontoclasts during physiological tooth shedding and to demonstrate that in vivo, local drug delivery is possible in the gecko model.

Identification of potential therapeutic targets for Alzheimer's disease from the proteomes of plasma and cerebrospinal fluid in a multicenter Mendelian randomization study

BACKGROUND

Certain peripheral proteins are believed to be involved in the development of Alzheimer's disease (AD), but the roles of other new protein biomarkers are still unclear. Current treatments aim to manage symptoms, but they are not effective in stopping the progression of the disease. New drug targets are needed to prevent Alzheimer's disease.

METHODS

We used Mendelian randomization (MR) to study drug targets for Alzheimer's disease. We analyzed data from the European Alzheimer's and Dementia Biobank consortium and replicated our findings in GWAS data from IGAP and FinnGen cohorts. We identified genetic instruments for plasma and cerebrospinal fluid (CSF) proteins and conducted sensitivity analyses using various methods. Additionally, a comparison and analysis of protein-protein interactions (PPI) were conducted to identify potential causal proteins. The implications of these findings were further explored through an examination of existing AD drugs and their respective targets.

RESULTS

Through MR analysis, 10 protein AD pairs were identified as statistically significant at the Bonferroni level (P < 6.35 × 10-5). The specific findings indicate that elevated levels of plasma cathepsin H (CTSH) (OR = 1.06, 95%CI: 1.03-1.08, p = 6.12 × 10-6), plasma signal regulatory protein alpha (SIRPA) (OR = 1.03, 95%CI: 1.02-1.05, p = 1.37 × 10-5), plasma TMEM106B (OR = 1.16, 95%CI: 1.09-1.23, p = 1.92 × 10-6), and CSF bone sialoprotein (BSP) (OR = 1.33, 95%CI: 1.17-1.51, p = 9.34 × 10-6), CSF Interleukin-34 (IL-34) (OR = 2.13, 95%CI: 1.51-3.01, p = 1.85 × 10-5), CSF immunoglobulin-like transcript 2 (ILT-2) (OR = 1.33, 95%CI: 1.17-1.51, p = 9.34 × 10-6) are associated with an increased risk of AD, while increased levels of plasma progranulin gene (GRN) (OR = 0.79, 95%CI: 0.74-0.84, p = 2.19 × 10-12), plasma triggering receptor expressed on myeloid cells 2 (TREM2) (OR = 0.67, 95%CI: 0.58-0.78, p = 6.95 × 10-8), plasma sialic acid-bind immunoglobulin-like lectins (SIGLEC)-9 (OR = 0.67, 95%CI: 0.58-0.78, p = 6.95 × 10-8), and CSF SIGLEC7 (OR = 0.42, 95%CI: 0.28-0.64, p = 4.30 × 10-5) are associated with a decreased risk of AD. Bayesian colocalization found that the above protein-related genes shared the same mutation as AD.

CONCLUSION

Increased levels of plasma CTSH, SIRPA, TMEM106B, CSF BSP, CSF IL-34, and CSF ILT-2 have been found to be correlated with an elevated risk of AD, whereas elevated levels of plasma GRN, TREM2, SIGLEC9, and CSF SIGLEC7 are associated with a decreased risk of developing AD. Further investigation through clinical trials is needed.

Genetic Insights Into the Role of Cathepsins in Alzheimer's Disease, Parkinson's Disease, and Amyotrophic Lateral Sclerosis: Evidence From Mendelian Randomization Study

BACKGROUND

Previous studies have confirmed the significant role of cathepsins in the development of neurodegenerative diseases. We aimed to determine whether genetically predicted 10 cathepsins may have a causal effect on Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS).

METHODS

We conducted a two-sample bidirectional Mendelian randomization (MR) study using publicly available data from genome-wide association study (GWAS) to assess the causal associations between 10 cathepsins and three neurodegenerative diseases, including AD, PD, and ALS. We employed the following methods, including inverse variance weighting (IVW), MR-Egger, and weighted median (WM). The results were further validated using sensitivity analysis.

RESULTS

The forward MR analysis results indicate that elevated cathepsin H levels increase the risk of AD (p = 0.005, odds ratio [OR] = 1.040, 95% confidence interval [CI] = 1.011-1.069), elevated cathepsin B levels decrease the risk of PD (p < 0.001, OR = 0.890, 95% CI = 0.831-0.954), and no significant association was found between cathepsin levels and ALS. Reverse MR analysis suggests that there is no causal association between 10 cathepsins and three neurodegenerative diseases.

CONCLUSION

Our study provides new genetic insights into the role of cathepsin H in AD and cathepsin B in PD. However, our findings need to be further validated in a wider population, and future research should explore the potential mechanisms of cathepsins in these diseases in order to provide a basis for the development of new therapeutic strategies.

Mendelian randomization analysis to explore the relationship between cathepsins and malignant ovarian tumors

Cysteine cathepsins are a family of lysosomal proteases that are often overexpressed in several human malignancies and haves been linked to cellular genomic alterations, disturbances in genomic stability, and the onset and spread of cancer. Recent studies have shown alterations in cysteine cathepsins in malignant ovarian tumors. However, it remains unclear whether there is a causal relationship between ovarian cancer, and its subtypes, and the cathepsin family. This study utilized two-sample Mendelian randomization (MR) analysis to examine this potential causal relationship. Genetic instruments derived from publicly available genetic summary data were used for the analyses. For MR analysis, the inverse-variance weighted method, weighted median method, and MR-Egger regression were employed. Multivariate MR analysis was performed concurrently. Univariate MR analysis indicated a strong correlation between decreased incidence of low-grade serous ovarian cancer and elevated levels of cathepsin L2 (odds ratio = 0.803, 95% confidence interval = 0.685-0.942, P = .007), whereas clear cell ovarian cancer showed a strong correlation with elevated levels of cathepsin H (odds ratio = 1.149, 95% confidence interval = 1.036-1.274, P = .008). Multivariate analysis, adjusted for 9 different cathepsins as covariates, confirmed the genetic relationships between cathepsin L2 and low-grade serous ovarian cancer and between cathepsin H and clear cell ovarian cancer. Our results suggest a causal relationship between cathepsins and ovarian malignancy and its subtypes. Cathepsin L2 has a protective effect on low-grade serous ovarian cancer, whereas cathepsin H is an adverse risk factor for clear cell ovarian cancer.

Compensational role between cathepsins

Cathepsins, a family of lysosomal peptidases, play a crucial role in maintaining cellular homeostasis by regulating protein turnover and degradation as well as many specific regulatory actions that are important for proper cell function and human health. Alterations in the activity and expression of cathepsins have been observed in many diseases such as cancer, inflammation, neurodegenerative disorders, bone remodelling-related conditions and others. These changes are not exclusively harmful, but rather appear to be a compensatory response on the lack of one cathepsin in order to maintain tissue integrity. The upregulation of specific cathepsins in response to the inhibition or dysfunction of other cathepsins suggests a fine-tuned system of proteolytic balance and understanding the compensatory role of cathepsins may improve therapeutic potential of cathepsin's inhibitors. Selectively targeting one cathepsin or modulating their activity could offer new treatment strategies for a number of diseases. This review emphasises the need for comprehensive research into cathepsin biology in the context of disease. The identification of the specific cathepsins involved in compensatory responses, the elucidation of the underlying molecular mechanisms and the development of targeted interventions could lead to innovative therapeutic approaches.

Mendelian randomisation analysis to explore the association between cathepsins and bipolar disorder

INTRODUCTION

Bipolar disorder is a psychiatric condition characterized by the coexistence of depression and mania. Diagnosis of this disorder can be challenging due to limited pathologic and experimental tools. Treatment compliance is often poor due to medication side effects. Although cathepsin is known to play a significant role in diseases such as tumors and osteoporosis, its role in psychiatric disorders is not yet fully understood.

OBJECTIVE

The aim of this study was to investigate the relationship between cathepsin in the blood circulation and bipolar disorder.

METHODS

The causal relationship between cathepsin and different subtypes of bipolar affective disorder was explored using bidirectional Mendelian randomization analysis and multivariate analysis.

RESULTS

It was found that cathepsin H level was a protective factor for type II bipolar disorder. No potential causal relationship was found between cathepsin H and type I bipolar disorder, but cathepsin B changes with the development of type I bipolar disorder. A causal relationship was found between cathepsin H and cerebral dopamine neurotrophic factor.

CONCLUSIONS

In conclusion, cathepsin H may be a diagnostic target for bipolar II disorder and may play a guiding role in clinical diagnosis. Cathepsin H may have an effect on BD through cerebral dopamine neurotrophic factor.

Multilevel Proteomics Reveals Epigenetic Signatures in BCG-Mediated Macrophage Activation

The bacillus Calmette-Guérin BCG vaccine (Mycobacterium bovis) is primarily used to prevent tuberculosis (TB) infections but has wide-ranging immunogenic effects. One of its most notable properties is its ability to induce trained immunity, a memory-like response in innate immune cells such as macrophages. Through targeted analyses of well-established histone marks, prior research has shown that these changes are generated through epigenetic modification. Mass spectrometry-based proteomic approaches provide a way to globally profile various aspects of the proteome, providing data to further identify unexplored mechanisms of BCG-mediated immunomodulation. Here we use multi-level proteomics (total, histone, and phospho to identify networks and potential mechanisms that mediate BCG-induced immunomodulation in macrophages. Histone-focused proteomics and total proteomics were performed at the University of Cape Town (data available via ProteomeXchange with identifier PXD051187), while phosphoproteomics data was retrieved from the ProteomeXchange Repository (identifier PXD013171). We identify several epigenetic mechanisms that may drive BCG-induced training phenotypes. Evidence across the proteomics and histone-focused proteomics data set pair 6 epigenetic effectors (NuA4, NuRD, NSL, Sin3A, SIRT2, SIRT6) and their substrates.

Causal effect of immune cells, metabolites, cathepsins, and vitamin therapy in diabetic retinopathy: a Mendelian randomization and cross-sectional study

Background

Diabetic retinopathy (DR) is a major microvascular complication of diabetes and a leading cause of blindness worldwide. The pathogenesis of DR involves complex interactions between metabolic disturbances, immune cells, and proteolytic enzymes such as cathepsins (CATs). Despite various studies, the precise roles of different CATs, metabolites, and vitamins in DR remain unclear.

Method

In this study, we employed Mendelian Randomization (MR) to assess causal relationships using genetic instruments selected based on genome-wide association studies (GWAS). We employed two-sample and mediation MR to explore the causal effects between nine CATs, immune cells, metabolites, vitamins, and DR. Additionally, the study also incorporated data from the NHANES survey to explore the associated relationship between vitamins and DR. We utilized cross-sectional data from the NHANES to analyze the association between vitamin intake and diabetic retinopathy (DR), adjusting for potential confounders to strengthen the validity of our findings.

Results

The MR analysis identified CAT H as a significant risk factor for both NPDR and PDR, with no evidence of reverse causality. Additionally, 62 immune cell traits were found to have causal relationships with NPDR and 49 with PDR. Enrichment analysis revealed that metabolic pathways such as sphingolipid metabolism are crucial in DR progression. Vitamins B6 and E were significantly associated with a reduced risk of PDR. Cross-sectional data indicated that vitamins B1, B2, B6, B12, and E progressively decreased with DR severity.

Conclusion

This study is the first to identify CAT H as a key risk factor for DR, while vitamins B6 and E showed significant protective effects, particularly against PDR. These findings suggest that CAT H, along with vitamins B6 and E, could serve as therapeutic targets for DR. Further validation through larger, multi-center studies is recommended to enhance the accuracy and applicability of these findings.

Can alterations in cathepsin levels restrain the development of skin cancer?: A bidirectional multivariate Mendelian-randomization study

Malignant skin tumors mainly include basal cell carcinoma, squamous cell carcinoma, and malignant melanoma. There is currently observational research suggesting that changes in cathepsin (CTS) may be a factor in the development of malignant skin tumors, but no studies have yet demonstrated a causal relationship between tissue protease changes and the occurrence of malignant skin tumors. Current studies have shown that cathepsin is involved in tumor cell invasion and metastasis by regulating growth factors and cellular immune function in tumor microenvironment, decomposing extracellular matrix and basement membrane, and promoting angiogenesis. In this study, we conducted a bidirectional Mendelian-randomization study using publicly available genome-wide association study (GWAS; GWAS Catalog) data. This study applies a bidirectional multivariate Mendelian randomization (MR) approach to investigate the causal relationship between cathepsin, basal cell carcinoma, squamous cell carcinoma, and malignant melanoma. In cases where multiple cathepsins are implicated as etiological factors in certain diseases, a multivariable analysis is conducted to assess the direct and indirect causal effects of the exposure factors. In this study, we present a comprehensive MR analysis to investigate the relationship between 9 cathepsin and basal cell carcinoma, squamous cell carcinoma, and malignant melanoma. Based on our MR analysis using the largest GWAS Catalog dataset available, we are able to draw relatively reliable conclusions. In the MR study, we found that tissue protease L2 can promote skin cancer, Cathepsin O, and Cathepsin F are associated with an increased risk of basal cell carcinoma. Cathepsin H can inhibit basal cell carcinoma and malignant melanoma. In the reverse MR study, it was found that squamous cell carcinoma may cause an increase in Cathepsin O expression. In the multivariate analysis, it was found that Cathepsin H is a direct factor in reducing the occurrence of skin cancer and melanoma, with no apparent causal relationship to non-melanoma skin cancer. Cathepsin has a dual impact on skin cancer cells, and the expression of different cathepsins at the edge of skin tumors may indicate different developmental tendencies of skin cancer. Cathepsin may serve as effective biomarkers for predicting tumors.

Identifying and Validating Extracellular Matrix-Related Gene CTSH in Diabetic Foot Ulcer Using Bioinformatics and Machine Learning

Background

Diabetic foot ulcer (DFU) is a serious clinical problem with high amputation and mortality rates, yet there is a lack of desirable therapy. While the extracellular matrix (ECM) contributes significantly to wound healing, ECM-related biomarker for DFU is still unknown. The study was designed to identify ECM-related biomarker in DFU using bioinformatics and machine learning and validate it in STZ-induced mice models.

Methods

GSE80178 and GSE134431 microarray datasets were fetched from the GEO database, and differentially expressed genes (DEGs) analysis was performed, respectively. By analyzing DEGs and ECM genes, we identified ECM-related DEGs, and functional enrichment analysis was conducted. Subsequently, three machine learning algorithms (LASSO, RF and SVM-RFE) were applied to filter ECM-related DEGs to identify key ECM-related biomarkers. Next, we conducted immune infiltration analysis, GSEA, and correlation analysis to explore the hub gene underlying mechanism. A lncRNA-miRNA-mRNA and drug regulatory network were constructed. Finally, we validated the key ECM-related biomarker in STZ-induced mice models.

Results

One hundred and forty-five common DEGs in adult DFU between the two datasets were identified. Taking the intersection of 145 common DEGs and 964 ECM genes, we identified 13 ECM-related DEGs. Thirteen ECM-related DEGs were mainly enriched in pathways associated with tissue remodeling, inflammation and defense against infectious agents. Ultimately, CTSH was identified as the key ECM-related biomarker. CTSH was associated with difference immune cells during the occurrence and development of DFU, and it influenced hedgehog, IL-17 and TNF signaling pathway. Additionally, CTSH expression is correlated with many ECM- and immune-related genes. A lncRNA-miRNA-mRNA and drug regulatory network were constructed with 10 lncRNAs, 2 miRNAs, CTSH and 1 drug. Finally, CTSH was validated as a key biomarker for DFU in animal models.

Conclusion

Our study found that CTSH can be used for both diagnostic and prognostic purposes and might be a potential therapeutic target.

Association between cathepsins and skin cancers: A bidirectional two-sample Mendelian randomization study

BACKGROUND

Several cathepsins have been identified as being involved in the development of cancer. Nevertheless, the connection between cathepsins and skin cancers remained highly elusive.

METHODS

A bidirectional Mendelian randomization (MR) analysis was performed to investigate the causal association between cathepsins and skin malignancies. The genome-wide association studies (GWAS) data for cathepsins, malignant melanoma (MM), and basal cell carcinoma (BCC) were obtained from European research. The primary method employed was inverse variance weighted. In addition, MR-Egger, weighted median, weighted mode, and simple mode were also executed. Sensitivity analysis was performed using Cochran's Q test, MR-Egger, and MR-PRESSO.

RESULTS

From univariable MR (UVMR), cathepsin H, and S were determined to have a causal relationship with BCC. Additionally, cathepsin H was identified as associated with MM. Multivariable MR (MVMR) showed that after correcting for risk factors of skin carcinoma, cathepsin H was detected to be protective against BCC, whereas cathepsin S has been observed as a risk factor for BCC. No substantial pleiotropy and heterogeneity were identified in the sensitivity analysis.

CONCLUSION

This study was the first to establish a direct link between cathepsins and skin malignancies. Cathepsin H and S have the potential to serve as new biomarkers for BCC, offering valuable assistance in the prompt identification, treatment, and prevention of the disease. Nevertheless, additional clinical trials are required to validate our findings.

Genetic insights into serum cathepsins as diagnostic and therapeutic targets in knee and hip osteoarthritis

Osteoarthritis (OA) is a chronic disease due to the deterioration of cartilage structure and function, involving the progressive degradation of the cartilage extracellular matrix. Cathepsins, lysosomal cysteine proteases, play pivotal roles in various biological and pathological processes, particularly in protein degradation. Excess cathepsins levels are reported to contribute to the development of OA. However, the causal relationship between the cathepsin family and knee and hip OA remains uncertain. Therefore, this study utilized bidirectional Mendelian Randomization (MR) analyses to explore this causal association. Our results indicated that elevated serum levels of cathepsin O increase the overall risk of knee OA, while increased serum levels of cathepsin H enhance the risk of hip OA. Conversely, the reverse MR analyses did not reveal a reverse causal relationship between them. In summary, OA in different anatomical locations may genetically result from pathological elevations in different serum cathepsin isoforms, which could be utilized as diagnostic and therapeutic targets in clinical practice.

Alterations in Blood Methylome as Potential Epigenetic Biomarker in Sporadic Parkinson's Disease

OBJECTIVE

To characterize DNA methylation (DNAm) differences between sporadic Parkinson's disease (PD) and healthy control (HC) individuals enrolled in the Parkinson's Progression Markers Initiative (PPMI).

METHODS

Using whole blood, we characterized longitudinal differences in DNAm between sporadic PD patients (n = 196) and HCs (n = 86) enrolled in PPMI. RNA sequencing (RNAseq) was used to conduct gene expression analyses for genes mapped to differentially methylated cytosine-guanine sites (CpGs).

RESULTS

At the time of patient enrollment, 5,178 CpGs were differentially methylated (2,683 hypermethylated and 2,495 hypomethylated) in PD compared to HC. Of these, 579 CpGs underwent significant methylation changes over 3 years. Several differentially methylated CpGs were found near the cytochrome P450 family 2 subfamily E member 1 (CYP2E1) gene. Additionally, multiple hypermethylated CpGs were associated with the N-myc downregulated gene family member 4 (NDRG4) gene. RNA-Seq analyses showed 75 differentially expressed genes in PD patients compared to controls. An integrative analysis of both differentially methylated sites and differentially expressed genes revealed 20 genes that exhibited hypomethylation concomitant with overexpression. Additionally, 1 gene, cathepsin H (CTSH), displayed hypermethylation that was associated with its decreased expression.

INTERPRETATION

We provide initial evidence of alterations in DNAm in blood of PD patients that may serve as potential epigenetic biomarker of disease. To evaluate the significance of these changes throughout the progression of PD, additional profiling at longer intervals and during the prodromal stages of disease will be necessary. ANN NEUROL 2024;95:1162-1172.

Cathepsins and cancer risk: a Mendelian randomization study

Background

Previous observational epidemiological studies reported an association between cathepsins and cancer, however, a causal relationship is uncertain. This study evaluated the causal relationship between cathepsins and cancer using Mendelian randomization (MR) analysis.

Methods

We used publicly available genome-wide association study (GWAS) data for bidirectional MR analysis. Inverse variance weighting (IVW) was used as the primary MR method of MR analysis.

Results

After correction for the False Discovery Rate (FDR), two cathepsins were found to be significantly associated with cancer risk: cathepsin H (CTSH) levels increased the risk of lung cancer (OR = 1.070, 95% CI = 1.027-1.114, P = 0.001, PFDR = 0.009), and CTSH levels decreased the risk of basal cell carcinoma (OR = 0.947, 95% CI = 0.919-0.975, P = 0.0002, P FDR = 0.002). In addition, there was no statistically significant effect of the 20 cancers on the nine cathepsins. Some unadjusted low P-value phenotypes are worth mentioning, including a positive correlation between cathepsin O (CTSO) and breast cancer (OR = 1.012, 95% CI = 1.001-1.025, P = 0.041), cathepsin S (CTSS) and pharyngeal cancer (OR = 1.017, 95% CI = 1.001-1.034, P = 0.043), and CTSS and endometrial cancer (OR = 1.055, 95% CI = 1.012-1.101, P = 0.012); and there was a negative correlation between cathepsin Z and ovarian cancer (CTSZ) (OR = 0.970, 95% CI = 0.949-0.991, P = 0.006), CTSS and prostate cancer (OR = 0.947, 95% CI = 0.902-0.944, P = 0.028), and cathepsin E (CTSE) and pancreatic cancer (OR = 0.963, 95% CI = 0.938-0.990, P = 0.006).

Conclusion

Our MR analyses showed a causal relationship between cathepsins and cancers and may help provide new insights for further mechanistic and clinical studies of cathepsin-mediated cancer.

Therapeutic cysteine protease inhibitors: a patent review (2018-present)

INTRODUCTION

Cysteine proteases are involved in a broad range of biological functions, ranging from extracellular matrix turnover to immunity. Playing an important role in the onset and progression of several diseases, including cancer, immune-related and neurodegenerative disease, viral and parasitic infections, cysteine proteases represent an attractive drug target for the development of therapeutic tools.

AREAS COVERED

Recent scientific and patent literature focusing on the design and study of cysteine protease inhibitors with potential therapeutic application has been reviewed.

EXPERT OPINION

The discovery of a number of effective structurally diverse cysteine protease inhibitors opened up new challenges and opportunities for the development of therapeutic tools. Mechanistic studies and the availability of X-ray crystal structures of some proteases, alone and in complex with inhibitors, provide crucial information for the rational design and development of efficient and selective cysteine protease inhibitors as preclinical candidates for the treatment of different diseases.

Interleukin-13: association with inflammation and cysteine proteolysis in varicose transformation of the vascular wall

The present review considers current data on the structure, functions and role of interleukin-13 in the pathogenesis of vascular wall varicose transformation in terms of proteolysis and inflammatory response. It is known that interleukin-13 is able to interact with transforming growth factor-1 in diseases associated with fibrosis. The latter activates fibroblasts and excessive formation of the extracellular matrix, thereby inducing fibrosis of the vascular wall, which is one of the links in the pathogenesis of varicose veins. Also, to date, there is evidence of the interleukin-13 participation in the induction of certain proteolytic enzymes synthesis, such as matrix metalloproteinases. For the latter, participation in the transformation of the venous wall has been proven to date. The remodeling of the venous wall itself can lead to an increase in the expression of proteinases, providing a proteolytic mechanism for changing the structural organization of the venous wall in varicose veins of the lower extremities. At the same time, the involvement of lysosomal cysteine proteinases remains poorly understood. The expression and production of individual cathepsins are regulated by biologically active molecules: interleukin-1, interleukin-6, tumor necrosis factor , which are directly involved in inflammatory reactions in the wall of varicose veins. In particular, venous pathology develops in a vicious circle of inflammation with the formation of abnormal venous blood flow, chronic venous hypertension and dilation, and the recruitment of leukocytes. This leads to a further, deeper, remodeling of the walls and valves of the veins, an increase in blood pressure and the release of pro-inflammatory mediators chemokines and cytokines. In connection with the above, in order to understand the mechanisms of proteolysis in the vascular wall in varicose veins of the lower extremities, it is important to have an idea about the possible interactions of interleukin-13 with transforming growth factor-1, inflammatory cytokines, and cathepsins.

Mendelian randomization analyses explore the relationship between cathepsins and lung cancer

Lung cancer, a major contributor to cancer-related fatalities worldwide, involves a complex pathogenesis. Cathepsins, lysosomal cysteine proteases, play roles in various physiological and pathological processes, including tumorigenesis. Observational studies have suggested an association between cathepsins and lung cancer. However, the causal link between the cathepsin family and lung cancer remains undetermined. This study employed Mendelian randomization analyses to investigate this causal association. The univariable Mendelian randomization analysis results indicate that elevated cathepsin H levels increase the overall risk of lung cancer, adenocarcinoma, and lung cancer among smokers. Conversely, reverse Mendelian randomization analyses suggest that squamous carcinoma may lead to increased cathepsin B levels. A multivariable analysis using nine cathepsins as covariates reveals that elevated cathepsin H levels lead to an increased overall risk of lung cancer, adenocarcinoma, and lung cancer in smokers. In conclusion, cathepsin H may serve as a marker for lung cancer, potentially inspiring directions in lung cancer diagnosis and treatment.

Acid Sphingomyelinase Deficiency Type B Patient-Derived Liver Organoids Reveals Altered Lysosomal Gene Expression and Lipid Homeostasis

Acid sphingomyelinase deficiency (ASMD) or Niemann-Pick disease type A (NPA), type B (NPB) and type A/B (NPA/B), is a rare lysosomal storage disease characterized by progressive accumulation of sphingomyelin (SM) in the liver, lungs, bone marrow and, in severe cases, neurons. A disease model was established by generating liver organoids from a NPB patient carrying the p.Arg610del variant in the SMPD1 gene. Liver organoids were characterized by transcriptomic and lipidomic analysis. We observed altered lipid homeostasis in the patient-derived organoids showing the predictable increase in sphingomyelin (SM), together with cholesterol esters (CE) and triacylglycerides (TAG), and a reduction in phosphatidylcholine (PC) and cardiolipins (CL). Analysis of lysosomal gene expression pointed to 24 downregulated genes, including SMPD1, and 26 upregulated genes that reflect the lysosomal stress typical of the disease. Altered genes revealed reduced expression of enzymes that could be involved in the accumulation in the hepatocytes of sphyngoglycolipids and glycoproteins, as well as upregulated genes coding for different glycosidases and cathepsins. Lipidic and transcriptome changes support the use of hepatic organoids as ideal models for ASMD investigation.