OBJECTIVETo observe p21-activated kinase 6 (PAK6) expression and its possible role after spinal cord injury (SCI) in adult rat.

METHODSSprague-Dawley rats were subjected to spinal cord injury. To explore the pathological and physiological significance of PAK6, the expression patterns and distribution of PAK6 were observed by Western blot, immunohistochemistry and immunofluorescence.

RESULTSWestern blot analysis showed PAK6 protein level was significantly up-regulated on day 2 and day 4, then reduced and had no up-regulation till day 14. Immunohistochemistry analysis showed that the expression of PAK6 was significantly increased on day 4 compared with the control group. Besides, double immunofluorescence staining showed PAK6 was primarily expressed in the neurons and astrocytes in the control group. While after injury, the expression of PAK6 was increased significantly in the astrocytes and neurons, and the astrocytes were largely proliferated. We also examined the expression of proliferating cell nuclear antigen (PCNA) and found its change was correlated with the expression of PAK6. Importantly, double immunofluorescence staining revealed that cell proliferation evaluated by PCNA appeared in many PAK6-expressing cells on day 4 after injury.

CONCLUSIONThe up-regulation of PAK6 in the injured spinal cord may be associated with glial proliferation.

Animals ; Astrocytes ; Rats ; Rats, Sprague-Dawley ; Spinal Cord Injuries ; metabolism ; Up-Regulation ; p21-Activated Kinases

The serine/threonine p21-activated kinases (PAKs), as main effectors of the Rho GTPases Cdc42 and Rac, represent a group of important molecular switches linking the complex cytoskeletal networks to broad neural activity. PAKs show wide expression in the brain, but they differ in specific cell types, brain regions, and developmental stages. PAKs play an essential and differential role in controlling neural cytoskeletal remodeling and are related to the development and fate of neurons as well as the structural and functional plasticity of dendritic spines. PAK-mediated actin signaling and interacting functional networks represent a common pathway frequently affected in multiple neurodevelopmental and neurodegenerative disorders. Considering specific small-molecule agonists and inhibitors for PAKs have been developed in cancer treatment, comprehensive knowledge about the role of PAKs in neural cytoskeletal remodeling will promote our understanding of the complex mechanisms underlying neurological diseases, which may also represent potential therapeutic targets of these diseases.
Animals ; Cytoskeleton/genetics* ; Humans ; Nervous System Diseases/genetics* ; Neurons/enzymology* ; Signal Transduction ; p21-Activated Kinases/metabolism*

OBJECTIVE: To investigate the clinical phenotype and genetic basis of a child with epilepsy and global developmental delay. METHODS: A child with epilepsy and global developmental delay who had visited West China Second University Hospital, Sichuan University on April 1, 2021 was selected as the study subject. Clinical data of the child were reviewed. Genomic DNA was extracted from peripheral blood samples of the child and his parents. Whole exome sequencing (WES) was carried out for the child, and candidate variant was verified by Sanger sequencing and bioinformatic analysis. A literature review was also carried out by searching databases such as Wanfang data knowledge service platform, China National Knowledge Infrastructure, PubMed, ClinVar and Embase to summarize the clinical phenotypes and genotypes of the affected children. RESULTS: The child was a 2-year-and-2-month-old male with epilepsy, global developmental delay and macrocephaly. Results of WES showed that the child has harbored a c.1427T>C variant of the PAK1 gene. Sanger sequencing confirmed that neither of his parents has carried the same variant. Only one similar case had been recorded by the dbSNP, OMIM, HGMD, and ClinVar databases. No frequency for this variant among Asian population was available in the ExAC, 1000 Genomes, and gnomAD databases. Prediction with IFT, PolyPhen-2, LRT, Mutation Taster, and FATHMM online software suggested that this variant is deleterious to the function of encoded protein. Based on the Standards and Guidelines for the Interpretation of Sequence Variants: A Joint Consensus Recommendation of the American College of Medical Genetics and Genomics (ACMG), the PAK1 gene c.1427T>C variant was determined to be likely pathogenic. CONCLUSION The PAK1 gene c.1427T>C variant probably underlay the epilepsy and global developmental delay in this child, which has provided a reference for the clinical diagnosis and genetic counseling in children with similar disorders.
Humans ; Male ; China ; Computational Biology ; Consensus ; Epilepsy/genetics* ; Genotype ; Mutation ; p21-Activated Kinases/genetics* ; Child, Preschool

Animals ; Gene Expression ; Mice ; Mice, Inbred Strains ; Spinal Cord ; metabolism ; Spinal Cord Injuries ; genetics ; metabolism ; p21-Activated Kinases ; genetics

OBJECTIVE: To explore the genetic etiology for a child with profound intellectual disabilities and obvious behavioral abnormalities. METHODS: A male child who had presented at the Zhongnan Hospital of Wuhan University on December 2, 2020 was selected as the study subject. Peripheral blood samples of the child and his parents were collected and subjected to whole exome sequencing (WES). Candidate variant was verified by Sanger sequencing. Short tandem repeat (STR) analysis was carried out to determine its parental origin. The splicing variant was also validated in vitro with a minigene assay. RESULTS: WES results revealed that the child had harbored a novel splicing variant of c.176-2A>G in the PAK3 gene, which was inherited from his mother. The results of minigene assay have confirmed aberrant splicing of exon 2. According to the guidelines from the American College of Medical Genetics and Genomics, it was classified as a pathogenic variant (PVS1+PM2_Supporting+PP3). CONCLUSION The novel splicing variant c.176-2A>G of the PAK3 gene probably underlay the disorder in this child. Above finding has expanded the variation spectrum of the PAK3 gene and provided a basis for genetic counseling and prenatal diagnosis for this family.
Child ; Female ; Humans ; Male ; Pregnancy ; Exons ; Intellectual Disability/genetics* ; Mothers ; Mutation ; p21-Activated Kinases/genetics* ; Parents ; RNA Splicing

p21-activated kinases (PAKs) are a family of serine/threonine protein kinases comprised of six isoform (PAK1-6), all of which are direct targets of the small GTPases Rac and Cdc42. PAKs have recently been shown to regulate various cellular activities, including cell motility, survival and proliferation, the organization and function of cytoskeleton and extracellular matrix, transcription and translation. PAKs are overexpressed or hyperactivated in several human tumor, such as breast cancer, gastric cancer, ovarian cancer etc., which makes them an attractive new therapeutic targets. Thus, there has been considerable interest in the development of inhibitors to the PAKs, as biological markers and leads for the development of therapeutics.
Biomarkers ; Breast Neoplasms ; Cell Movement ; Cytoskeleton ; Extracellular Matrix ; Humans ; Monomeric GTP-Binding Proteins ; Ovarian Neoplasms ; p21-Activated Kinases ; Protein Kinase Inhibitors ; Protein Kinases ; Signal Transduction ; Stomach Neoplasms

p21-activated kinases (PAKs) are key regulators of actin dynamics, cell proliferation and cell survival. Deregulation of PAK activity contributes to the pathogenesis of various human diseases, including cancer and neurological disorders. Using an ELISA-based screening protocol, we identified naphtho(hydro)quinone-based small molecules that allosterically inhibit PAK activity. These molecules interfere with the interactions between the p21-binding domain (PBD) of PAK1 and Rho GTPases by binding to the PBD. Importantly, they inhibit the activity of full-length PAKs and are selective for PAK1 and PAK3 in vitro and in living cells. These compounds may potentially be useful for determining the details of the PAK signaling pathway and may also be used as lead molecules in the development of more selective and potent PAK inhibitors.
Actins ; Cell Proliferation ; Cell Survival ; Humans ; In Vitro Techniques ; Mass Screening ; Nervous System Diseases ; p21-Activated Kinases ; Phosphotransferases* ; rho GTP-Binding Proteins

p21-activated kinases (PAKs) are key regulators of actin dynamics, cell proliferation and cell survival. Deregulation of PAK activity contributes to the pathogenesis of various human diseases, including cancer and neurological disorders. Using an ELISA-based screening protocol, we identified naphtho(hydro)quinone-based small molecules that allosterically inhibit PAK activity. These molecules interfere with the interactions between the p21-binding domain (PBD) of PAK1 and Rho GTPases by binding to the PBD. Importantly, they inhibit the activity of full-length PAKs and are selective for PAK1 and PAK3 in vitro and in living cells. These compounds may potentially be useful for determining the details of the PAK signaling pathway and may also be used as lead molecules in the development of more selective and potent PAK inhibitors.
Actins ; Cell Proliferation ; Cell Survival ; Humans ; In Vitro Techniques ; Mass Screening ; Nervous System Diseases ; p21-Activated Kinases ; Phosphotransferases* ; rho GTP-Binding Proteins

OBJECTIVETo study the role of p21-activated kinase-4 (PAK4) in the occurrence, progression and metastasis of breast cancer.

METHODPAK4 expression was detected in 35 cases of normal breast, 22 breast cystic hyperplasia, 28 breast adenofibroma, 37 breast cancer (including 7 non-invasive cancer, 9 early invasive cancer and 21 invasive cancer) and 13 metastatic breast cancer tissues using immunohistochemistry for a comparison of PAK4 expression and distribution.

RESULTSPAK4 was expressed mainly in the cytoplasm of the cancer cells, occasionally in the cell nuclei, and virtually not expressed in the matrix surrounding the breast cells. PAK4 positivity rates increased in the order of normal breast tissues, benign changes (including breast cystic hyperplasea and breast adenoma), breast cancer and metastatic cancer tissues; in the cancer tissues, the positivity rates increased in the order of non-invasive breast tumor, early invasive tumor and invasive tumor tissues.

CONCLUSIONPAK4 is closely correlated to the progression and metastasis of breast cancer and may become a new diagnostic and therapeutic target of breast cancer.

Adult ; Aged ; Biomarkers, Tumor ; genetics ; metabolism ; Breast Neoplasms ; metabolism ; pathology ; Female ; Humans ; Middle Aged ; Neoplasm Invasiveness ; Neoplasm Metastasis ; Young Adult ; p21-Activated Kinases ; genetics ; metabolism

OBJECTIVETo investigate the effects of epigallocatechin-3-gallate (EGCG) on the proliferation of SW620 cells and the expression of PAK1 gene.

METHODSHuman colonic cancer cell line SW620 was treated with EGCG at 40, 60 and 80 micromol/L and cultured in RPMI 1640 medium for 0, 24, 48 and 72 h. The proliferation of SW620 cells was observed by MTT assay before and after EGCG treatment, and the expression of PAK1 protein was observed by Western blotting.

RESULTSSW620 cells treated with EGCG displayed a slowed growth in comparison with the control cells, and the growth rate decreased with the increase of EGCG concentration. PAK1 protein expression was lowered in SW620 cells after EGCG treatment for 48 h.

CONCLUSIONEGCG can inhibit the proliferation and partially reduce the expression of PAK1 protein in SW620 cells.

Blotting, Western ; Catechin ; analogs & derivatives ; pharmacology ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Colonic Neoplasms ; genetics ; pathology ; Gene Expression Regulation, Neoplastic ; drug effects ; Humans ; p21-Activated Kinases ; metabolism