LIM kinase-1 (LIMK1) and LIM kinase-2 (LIMK2) are kinases that have serine/threonine and tyrosine dual specificity. Although they show significant structural similarity, LIMK1 and LIMK2 have different expression patterns, subcellular localization, and functions. Activation of LIM kinases regulates the downstream of Rho GTPases, and influences the architecture of the actin cytoskeleton by regulating the activity of cofilin. Recent studies have shown that LIM kinases play important roles in the nervous system. For example, development of the central nervous system is reliant upon the presence of LIMK1, and deletion of Limk1 gene is involved in the development of the human genetic disorder Williams syndrome. Therefore, it is of vital physiological significance to investigate the neuronal function of LIM kinases. In this review, we outline the structure, phosphorylation regulation and neuronal function of LIM kinases, so as to provide new ideas for the treatment of these neurological diseases.
Animals ; Humans ; Lim Kinases ; chemistry ; metabolism ; physiology ; Nervous System ; enzymology

OBJECTIVETo perform genetic analysis for two patients with supravalvular aortic stenosis and unusual facial features.

METHODSCytogenetic and molecular genetic methods including chromosome karyotyping, multiplex ligation-dependent probe amplification (MLPA) and single nucleotide polymorphism array (SNP-array) were performed to detect potential mutation in the patients.

RESULTSNo abnormal karyotype was detected in either patient. Deletions in 7q11.23 region (1.36 Mb and 1.73 Mb, respectively) were discovered by SNP-array for the two patients. In both patients, de novo heterozygous deletion of ELN and LIMK1 genes was confirmed by MLPA analysis.

CONCLUSIONThe genotypes of the two patients were identified by molecular genetic analysis, which has facilitated interpretation of the phenotypes of these patient. According to the deletion mutation, prenatal diagnosis for the family could be performed in the future.

Child ; Chromosome Deletion ; Chromosomes, Human, Pair 7 ; genetics ; Female ; Genotype ; Humans ; Infant ; Lim Kinases ; genetics ; Male ; Phenotype ; Williams Syndrome ; genetics

OBJECTIVETo investigate the effect of cytoskeleton reorganization inhibition with RNA interference on the activation of extracellular signal-regulated kinase (ERK1/2) in primary osteoblasts induced by fluid shear stress (FSS).

METHODSBALB/c mouse primary cultured osteoblasts were isolated by enzyme digestion technique. Osteoblasts were treated with LIM domain kinase 2 (LIM-2) specific siRNA or negative control siRNA, and then were loaded or unloaded by FSS of 1.2 Pa for 0, 5, 15, 30 and 60 min, respectively. The Western blotting was performed to detect the protein expression levels of P-ERK1/2 and ERK1/2, respectively. Two-way ANOVA and one-way ANOVA were used in data analysis.

RESULTSFSS loading for different time (0, 5, 15, 30, 60 min) treated with negative RNA inteference had significant effect on the levels of P-ERK/ERK ratio (0.047 ± 0.031, 0.253 ± 0.137, 0.390 ± 0.155, 0.613 ± 0.123, 0.680 ± 0.108, respectively, P < 0.01). Statistical analysis showed that there was significant interaction between FSS and cytoskeleton reorganization inhibition treated with RNA inteference on the levels of P-ERK/ERK ratio (P < 0.01). The levels of P-ERK/ERK ratio increased when osteoblasts were loaded for 5 - 15 min (0.623 ± 0.129 and 0.623 ± 0.064, respectively, P < 0.05) and returned to baseline at 30 min (0.333 ± 0.086), and then reached the peak at 60 min (0.667 ± 0.064, P < 0.01).

CONCLUSIONSFSS could activate ERK1/2 rapidly in primary cultured osteoblasts. Cytoskeleton reorganization inhibition treated with RNA interference speeded-up the activation of ERK1/2 by FSS, which could increase the sensitivity of ERK1/2 to FSS.

Animals ; Cells, Cultured ; Cytoskeleton ; metabolism ; physiology ; Lim Kinases ; genetics ; metabolism ; Mechanotransduction, Cellular ; Mice ; Mice, Inbred BALB C ; Mitogen-Activated Protein Kinase 1 ; metabolism ; Mitogen-Activated Protein Kinase 3 ; metabolism ; Osteoblasts ; cytology ; enzymology ; Phosphorylation ; RNA Interference ; RNA, Small Interfering ; Stress, Mechanical

We evaluated whether LIM-kinase 2 inhibitor (LIMK2i) could improve erectile function by suppressing corporal fibrosis through the normalization of the Rho-associated coiled-coil protein kinase 1 (ROCK1)/LIMK2/Cofilin pathway in a rat model of cavernous nerve crush injury (CNCI). Sixty 11-week-old male Sprague-Dawley rats were divided equally into five groups: sham surgery (S), CNCI (I), and CNCI treated with low-dose (L), medium-dose (M), and high-dose (H) LIMK2i. The L, M, and H groups were treated with a daily intraperitoneal injection of LIMK2i (2.5, 5.0, and 10.0 mg kg^-1 body weight, respectively) for 1 week after surgery. The erectile response was assessed using electrostimulation at 1 week, postoperatively. Penile tissues were processed for Masson's trichrome staining, double immunofluorescence, and Western blot assay. Erectile responses in the H group improved compared with the I group, while the M group showed only partial improvement. A significantly decreased smooth muscle/collagen ratio and an increased content of fibroblasts positive for phospho-LIMK2 were noted in the I group. The M and H groups revealed significant improvements in histological alterations and the dysregulated LIMK2/Cofilin pathway, except for LIMK2 phosphorylation in the M group. The inhibition of LIMK2 did not affect the ROCK1 protein expression. The content of fibroblasts positive for phospho-LIMK2 in the H group returned to the level found in the S group, whereas it did not in the M group. However, the L group did not exhibit such improvements. Our data suggest that the inhibition of LIMK2, particularly with administration of 10.0 mg kg^-1 body weight LIMK2i, can improve corporal fibrosis and erectile function by normalizing the LIMK2/Cofilin pathway.
Animals ; Cofilin 1/metabolism* ; Electric Stimulation ; Erectile Dysfunction/etiology* ; Fibroblasts/pathology* ; Fibrosis/drug therapy* ; Lim Kinases/antagonists & inhibitors* ; Male ; Penile Diseases/drug therapy* ; Penis/innervation* ; Peripheral Nerve Injuries/pathology* ; Phosphorylation ; Rats ; Rats, Sprague-Dawley ; Signal Transduction/drug effects* ; rho-Associated Kinases/genetics*

Lipoma preferred partner (LPP) has been identified as a protein which is highly selective for smooth muscle progenitor cells (SMPCs) and regulates differentiation and migration of SMPCs, but mechanisms of LPP expression are not elucidated clearly. The aim of the present study was to discuss the mechanisms by which LPP expression is regulated in the differentiation and migration of SMPCs induced by TGF-β1. It was found that TGF-β1 could significantly increase the expression of LPP, smooth muscle α-actin, smooth muscle myosin heavy chain (SM-MHC), and smoothelin in SMPCs. Moreover, inactivation of Rho kinase (ROK) with ROK inhibitors significantly inhibited LPP mRNA expression in TGF-β1-treated SMPCs and mouse aortic smooth muscle cells (MAoSMCs). At the same time, LPP silencing with short interfering RNA significantly decreased SMPCs migration. In conclusion, LPP appears to be a ROK-dependant SMPCs differentiation marker that plays a role in regulating SMPCs migration.
Animals ; Bone Marrow ; metabolism ; physiology ; Cell Differentiation ; genetics ; Cell Movement ; genetics ; Cells, Cultured ; Cytoskeletal Proteins ; genetics ; metabolism ; LIM Domain Proteins ; genetics ; metabolism ; Mice ; Mice, Inbred C57BL ; Muscle, Smooth ; metabolism ; physiology ; Stem Cells ; metabolism ; physiology ; Transforming Growth Factor beta1 ; genetics ; metabolism ; rho-Associated Kinases ; genetics ; metabolism

In recent years, human cancer genome projects provide unprecedented opportunities for the discovery of cancer genes and signaling pathways that contribute to tumor development. While numerous gene mutations can be identified from each cancer genome, what these mutations mean for cancer is a challenging question to address, especially for those from less understood putative new cancer genes. As a powerful approach, in silico bioinformatics analysis could efficiently sort out mutations that are predicted to damage gene function. Such an analysis of human large tumor suppressor genes, LATS1 and LATS2, has been carried out and the results support a role of hLATS1//2 as negative growth regulators and tumor suppressors.
Adaptor Proteins, Signal Transducing ; chemistry ; metabolism ; Animals ; Carrier Proteins ; chemistry ; metabolism ; Computational Biology ; Genes, Neoplasm ; Humans ; LIM Domain Proteins ; chemistry ; metabolism ; Mice ; Mutation ; Neoplasms ; genetics ; pathology ; Phosphoproteins ; chemistry ; metabolism ; Phosphorylation ; Protein Binding ; Protein Structure, Tertiary ; Protein-Serine-Threonine Kinases ; chemistry ; genetics ; metabolism ; Transferases (Other Substituted Phosphate Groups) ; chemistry ; metabolism ; Tumor Suppressor Proteins ; chemistry ; genetics ; metabolism

We aimed to determine whether combination of LIM-kinase 2 inhibitor (LIMK2i) and phosphodiesterase type-5 inhibitor (PDE5i) could restore erectile function through suppressing cavernous fibrosis and improving cavernous apoptosis in a rat model of cavernous nerve crush injury (CNCI). Seventy 12-week-old Sprague-Dawley rats were equally distributed into five groups as follows: (1) sham surgery (Group S), (2) CNCI (Group I), (3) CNCI treated with daily intraperitoneal administration of 10.0 mg kg^-1 LIMK2i (Group I + L), (4) daily oral administration of 20.0 mg kg^-1 udenafil, PDE5i (Group I + U), and (5) combined administration of 10.0 mg kg^-1 LIMK2i and 20.0 mg kg^-1 udenafil (Group I + L + U). Rats in Groups I + L, I + U, and I + L + U were treated with respective regimens for 2 weeks after CNCI. At 2 weeks after surgery, erectile response was assessed using electrostimulation. Penile tissues were processed for histological studies and western blot. Group I showed lower intracavernous pressure (ICP)/mean arterial pressure (MAP), lower area under the curve (AUC)/MAP, decreased immunohistochemical staining for alpha-smooth muscle (SM) actin, higher apoptotic index, lower SM/collagen ratio, increased phospho-LIMK2-positive fibroblasts, decreased protein kinase B/endothelial nitric oxide synthase (Akt/eNOS) phosphorylation, increased LIMK2/cofilin phosphorylation, and increased protein expression of fibronectin, compared to Group S. In all three treatment groups, erectile responses, protein expression of fibronectin, and SM/collagen ratio were improved. Group I + L + U showed greater improvement in erectile response than Group I + L. SM content and apoptotic index in Groups I + U and I + L + U were improved compared to those in Group I. However, Group I + L did not show a significant improvement in SM content or apoptotic index. The number of phospho-LIMK2-positive fibroblasts was normalized in Groups I + L and I + L + U, but not in Group I + U. Akt/eNOS phosphorylation was improved in Groups I + U and I + L + U, but not in Group I + L. LIMK2/cofilin phosphorylation was improved in Groups I + L and I + L + U, but not in Group I + U. Our data indicate that combined treatment of LIMK2i and PDE5i immediate after CN injury could improve erectile function by improving cavernous apoptosis or eNOS phosphorylation and suppressing cavernous fibrosis. Rectification of Akt/eNOS and LIMK2/cofilin pathways appears to be involved in their improvement.
Animals ; Apoptosis/drug effects* ; Arterial Pressure ; Electric Stimulation ; Erectile Dysfunction/pathology* ; Lim Kinases/antagonists & inhibitors* ; Male ; Nerve Crush ; Nitric Oxide Synthase Type III/metabolism* ; Penis/pathology* ; Peripheral Nerve Injuries/pathology* ; Phosphodiesterase 5 Inhibitors/therapeutic use* ; Phosphorylation ; Pyrimidines/therapeutic use* ; Rats ; Rats, Sprague-Dawley ; Sulfonamides/therapeutic use*