Proteomics and functional study reveal kallikrein-6 enhances communicating hydrocephalus

Background Communicating hydrocephalus (CH) is a common neurological disorder caused by a blockage of cerebrospinal fluid. In this study, we aimed to explore the potential molecular mechanism underlying CH development. Methods Quantitative proteomic analysis was performed to screen the differentially expressed proteins (DEPs) between patients with and without CH. A CH rat model was verified by Hoechst staining, and the co-localization of the target protein and neuron was detected using immunofluorescence staining. Loss-of-function experiments were performed to examine the effect of KLK6 on the synapse structure. Results A total of 11 DEPs were identified, and kallikrein 6 (KLK6) expression was found to be significantly upregulated in patients with CH compared with that in patients without CH. The CH rat model was successfully constructed, and KLK6 was found to be co-localized with neuronal nuclei in brain tissue. The expression level of IL-1β, TNF-α, and KLK6 in the CH group was higher than that in the control group. After knockdown of KLK6 expression using small-interfering RNA (siRNA), the expression levels of synapsin-1 and PSD95 in neuronal cells were increased, and the length, number, and structure of synapses were significantly improved. Following siRNA interference KLK6 expression, 5681 differentially expressed genes (DEGs) were identified in transcriptome profile. The upregulated DEGs of Appl2, Nav2, and Nrn1 may be involved in the recovery of synaptic structures after the interference of KLK6 expression. Conclusions Collectively, KLK6 participates in the development of CH and might provide a new target for CH treatment.

The Treatment of Alzheimer’s Disease through Molecular Docking Studies using Phyltetralin against Kallikrein_6: A Bioinformatic Approach

Alzheimer's disease (AD) is a neurodegenerative disease that generally begins leisurely and gets worse with time. Alzheimer’s disease (AD) dementia is the specific beginning of age-related declination of cognitive abilities and function, which eventually leads to death. Alzheimer’s disease (AD) is one of the neurodeteriorating disorders which is one of the mostcritical complications that our current health care system faces. The phenomenon of molecular docking has progressively become a strong tool in the field of pharmaceutical research including drug discovery. The aim of the presentin silico study was to inhibit the expression of KLK-6 (kallikrein-6) which is a target or receptor protein by its interaction with three distinct secondary metabolites for treating Alzheimer's disease (AD) through molecular docking. Methods: The in-silico study was based on molecular docking. Docking was executed amidst ligands- Quercetin (CID: 5280343), Ricinoleic Acid (CID: 643684), Phyltetralin (CID: 11223782), and the target or receptor protein Kallikrein-6 (PDB ID: 1LO6). The protein and the ligands were downloaded in the required format. Through PyRx, the ligands were virtually screened after importing them in the PyRx window. The results of PyRx and SwissADME were analyzed and the best ligand was finalized. Among the three, Phyltetralin was the best ligand contrary to KLK-6 having minimum binding energy and it was following Lipinski’s five rules along with 0 violations. Results: The final docking was carried out between Phyltetralin and KLK-6 through AutoDock Vina. The outcome showed 9 poses with distinct binding energy, RSMD LB (root mean square deviation lower bound) and RSMD UB (root mean square deviation upper bound). With the help of PyMOL which is an open-access tool for molecular visualization, the interaction amidst Phyltetralin and KLK-6 can be visualized. Conclusion: Based on this in silico study it can be concluded that KLK-6 (kallikrein-6) which is responsible for causing AD can be inhibited by ligand Phyltetralin and for the treatment of AD, phyltetralin might act as a potential drug. Thus, in future studies, Phyltetralin from natural sources can prevent Alzheimer's disease and can be proved as a promising and efficient drug for treating Alzheimer's disease.

Proteomic and Functional Analyses Reveal That Kallikrein 6 Enhances Communicating Hydrocephalus by Injuring Neuronal Synapses

Communicating hydrocephalus (CH) is a common neurological disorder caused by a blockage of cerebrospinal fluid. In this study, we aimed to explore the potential molecular mechanism underlying CH development. Quantitative proteomic analysis was performed to screen the differentially expressed proteins (DEPs) between patients with and without CH. A CH rat model was verified by Hoechst staining, and the co-localization of the target protein and neuron was detected using immunofluorescence staining. Loss-of-function experiments were performed to examine the effect of KLK6 on the synapse structure. A total of 11 DEPs were identified, and kallikrein 6 (KLK6) expression was found to be significantly upregulated in patients with CH compared with that in patients without CH. The CH rat model was successfully constructed, and KLK6 was found to be co-localized with neuronal nuclei in brain tissue. The expression level of KLK6 in the CH group was higher than that in the control group. After interference of KLK6 expression, the expression levels of synapsin-1 and PSD95 in neuronal cells were increased, and the length, number, and structure of synapses were significantly improved. The transcriptome profile (PRJNA719985) after interference of KLK6 expression was obtained, and 5,681 differentially expressed genes (DEGs) were identified. The upregulated DEGs of Appl2, Nav2, and Nrn1 may be involved in the recovery of synaptic structures after interference of KLK6 expression. Collectively, KLK6 participates in the development of CH and might provide a new target for CH treatment.

Molecular Pathways Associated with Kallikrein 6 Overexpression in Colorectal Cancer

Colorectal cancer (CRC) remains one of the leading causes of cancer-related death worldwide. The high mortality of CRC is related to its ability to metastasize to distant organs. The kallikrein-related peptidase Kallikrein 6 (KLK6) is overexpressed in CRC and contributes to cancer cell invasion and metastasis. The goal of this study was to identify KLK6-associated markers for the CRC prognosis and treatment. Tumor Samples from the CRC patients with significantly elevated KLK6 transcript levels were identified in the RNA-Seq data from Cancer Genome Atlas (TCGA) and their expression profiles were evaluated using Gene Ontology (GO), Phenotype and Reactome enrichment, and protein interaction methods. KLK6-high cases had a distinct spectrum of mutations in titin (TTN), APC, K-RAS, and MUC16 genes. Differentially expressed genes (DEGs) found in the KLK6-overexpressing CRCs were associated with cell signaling, extracellular matrix organization, and cell communication regulatory pathways. The top KLK6-interaction partners were found to be the members of kallikrein family (KLK7, KLK8, KLK10), extracellular matrix associated proteins (keratins, integrins, small proline rich repeat, S100A families) and TGF-β, FOS, and Ser/Thr protein kinase signaling pathways. Expression of selected KLK6-associated genes was validated in a subset of paired normal and tumor CRC patient-derived organoid cultures. The performed analyses identified KLK6 itself and a set of genes, which are co-expressed with KLK6, as potential clinical biomarkers for the management of the CRC disease.

Molecular pathways associated with Kallikrein 6 overexpression in colorectal cancer

Colorectal cancer (CRC) remains one of leading causes of cancer-related death worldwide. The high mortality of CRC is related to its ability to metastasize to distant organs. Current management of the CRC disease is limited due to the need of more extensive molecular characterization of tumor biomarkers. Kallikrein 6 (KLK6) is a member of the fifteen-gene family of kallikrein-related peptidases. KLK6 is overexpressed in CRC and contributes to cancer cell invasion through its proteolytic degradation of the extracellular matrix and recently discovered regulation of metastasis signaling pathways.The goal of this study was to evaluate the clinical features, CRC molecular subtypes, mutational and gene expression patterns of the CRC tumors with overexpressed KLK6 in order to identify KLK6-associated markers for the CRC prognosis and treatment. RNA-Seq data from the CRC patients with a significantly elevated KLK6 transcript levels (KLK6-high group) (Z-score higher than-1.96) were identified in the Cancer Genome Atlas (TCGA) database and processed for clinical, molecular evaluation and bioinformatic analysis, using Gene Ontology (GO), Phenotype and Reactome enrichment and protein interaction methods. KLK6-high cases had a distinct spectrum of mutations in titin (TTN), APC, K-RAS and MUC 16 genes. Differentially expressed genes (DEGs) unique to KLK6-high group were clustered to regulatory pathways controlling the cell signaling, extracellular matrix organization, and cell communication regulation. The members of kallikrein family (KLK7, KLK8, KLK10), keratins (KRT6A, 6B, 15, 16, 19, 80), extracellular matrix proteins (integrin 4B), small proline rich repeat proteins (SPRRs), S100A families, protein trafficking genes (SYL1) and signaling genes within TGF-β, FOS and Ser/Thr protein kinase pathways were recognized as the top KLK6-interaction partners. Expression of selected KLK6-associated genes was validated in a subset of paired normal and tumor CRC patient-derived organoid cultures.The performed analyses identified KLK6 itself and a set of genes, which are co-expressed with KLK6, as potential clinical biomarkers for the management of the CRC disease.