Targeting Kindlin-2 in adipocytes increases bone mass through inhibiting FAS/PPARγ/FABP4 signaling in mice

Osteoporosis (OP) is a systemic skeletal disease that primarily affects the elderly population, which greatly increases the risk of fractures. Here we report that Kindlin-2 expression in adipose tissue increases during aging and high-fat diet fed and is accompanied by decreased bone mass. Kindlin-2 specific deletion (K2KO) controlled by Adipoq-Cre mice or adipose tissue-targeting AAV (AAV-Rec2-CasRx-sgK2) significantly increases bone mass. Mechanistically, Kindlin-2 promotes peroxisome proliferator-activated receptor gamma (PPARγ) activation and downstream fatty acid binding protein 4 (FABP4) expression through stabilizing fatty acid synthase (FAS), and increased FABP4 inhibits insulin expression and decreases bone mass. Kindlin-2 inhibition results in accelerated FAS degradation, decreased PPARγ activation and FABP4 expression, and therefore increased insulin expression and bone mass. Interestingly, we find that FABP4 is increased while insulin is decreased in serum of OP patients. Increased FABP4 expression through PPARγ activation by rosiglitazone reverses the high bone mass phenotype of K2KO mice. Inhibition of FAS by C75 phenocopies the high bone mass phenotype of K2KO mice. Collectively, our study establishes a novel Kindlin-2/FAS/PPARγ/FABP4/insulin axis in adipose tissue modulating bone mass and strongly indicates that FAS and Kindlin-2 are new potential targets and C75 or AAV-Rec2-CasRx-sgK2 treatment are potential strategies for OP treatment.

Effect of c-CBL overexpression on activation of astrocytes in spinal cord of rats with neuropathic pain: relationship with Kindlin-1 / 中华麻醉学杂志

Objective:To evaluate the effect of c-CBL overexpression on activation of astrocytes in the spinal cord of rats with neuropathic pain and the relationship with Kindlin-1.Methods:Eighteen clean-grade healthy male Sprague-Dawley rats, aged 10-12 weeks, weighing 250-280 g, were divided into 3 groups ( n=6 each) using a random number table method: sham operation group (S group), neuropathic pain group (NP group) and c-CBL overexpression group (c-CBL group). The model of neuropathic pain was developed by chronic compression of the sciatic nerve in anesthetized rats.On 1 day before operation, c-CBL overexpression vector 10 μl was intrathecally injected in group c-CBL, while blank vehicle 10 μl was intrathecally injected in S and NP groups.The mechanical paw withdrawal threshold (MWT) and thermal paw withdrawal latency (TWL) were measured on 1 day before operation (T 0) and 1, 4 and 7 days after operation (T 1-3). The rats were sacrificed by decapitation after measurement of the pain threshold at T 3, and the spinal cord of L 4-6 was taken for determination of the expression of Kindlin-1, glial fibrillary acidic protein (GFAP), tumor necrosis factor-alpha (TNF-α), and interleukin-1beta (IL-1β) (by Western blot) and co-expression of Kindlin-1 with c-CBL (by co-immunoprecipitation). Results:Compared with group S, the MWT was significantly decreased and TWL was shortened at T 2, 3 in group NP and group c-CBL, the expression of Kindlin-1, GFAP, TNF-α and IL-1β was significantly up-regulated in group NP, and the expression of c-CBL was significantly up-regulated in group c-CBL ( P<0.05). Compared with group NP, the MWT was significantly increased and TWL was prolonged at T 2, 3, the expression of Kindlin-1, GFAP, TNF-α and IL-1β was down-regulated, and the expression of c-CBL was up-regulated in group c-CBL ( P<0.05). The results of co-immunoprecipitation showed that there was a protein interaction and co-expression relationship between Kindlin-1 and c-CBL in group NP, and the co-expression of Kindlin-1 with c-CBL was enhanced in group c-CBL when compared with group NP. Conclusions:The overexpression of c-CBL can inhibit activation of astrocytes by down-regulating the expression of Kindlin-1 in the spinal cord, thus reducing inflammatory responses and relieving neuropathic pain in rats.

Relationship between spinal lncRNA and kindlin-1/Wnt3a signaling pathway in a rat model of neuropathic pain / 中华麻醉学杂志

Objective:To investigate the relationship between spinal long chain noncoding RNA (lncRNA) and kindlin-1/Wnt3a signaling pathway in a rat model of neuropathic pain (NP).Methods:The experiment was performed in two parts.Experiment Ⅰ Sprague-Dawley rats of both sexes, aged 7 days, weighing 15-20 g, were selected.Rats were sacrificed, the dorsal horn of spinal cord was removed, and the primary astrocytes were extracted and cultured.Lipopolysaccharide 1 μg/ml was added to induce the activation of astrocytes for 24 h. The lncRNA binding to kindlin-1 was identified using PCR immunoprecipitation method.The localization of lncRNA FOXF1-AS1 in astrocytes was observed by fluorescence in situ hybridization, and the binding between lncRNA FOXF1-AS1 and kindlin-1 was detected by biotin-labeled magnetic bead method.Experiment Ⅱ Thirty clean-grade healthy male Sprague-Dawley rats, aged 10-12 weeks, weighing 250-280 g, were divided into 5 groups ( n=6 each) using a random number table method: sham operation control group (group C), NP group, lncRNA FOXF1-AS1 overexpression group (group F), lncRNA FOXF1-AS1 overexpression plus kindlin-1 shRNA group (group FK) and lncRNA FOXF1-AS1 overexpression + Wnt inhibitor group (group FW). NP was induced by chronic constrictive injury in anesthetized animals.In group F, lncRNA FOXF1-AS1 overexpression lentivirus 10 μl was intrathecally injected at 28 days before operation, and vector virus 10 μl was intrathecally injected in the other groups.In FK group, kindlin-1 interfering shRNA interference adenovirus 10 μl, and vector virus 10 μl was intrathecally injected in the other groups.In group FW, Wnt inhibitor IWP-2 10 μl was intrathecally injected at 1-3 days after operation, artificial cerebrospinal fluid 10 μl was intrathecally injected at the same time point in the other groups.Mechanical withdrawal threshold (MWT) and thermal withdrawal latency (TWL) were measured at 1 day before operation, at 4 days and 7 days after operation.The animals were sacrificed at the end of measurement of pain threshold at 7 days after operation, and the spinal cord tissues were taken for determination of the expression of kindlin-1, Wnt3a and glial fibrillary acidic protein (GFAP) (by Western blot) and the contents of tumor necrosis factor (TNF)-α and interleukin (IL)-1β (IL-1β) (using enzyme-linked immunosorbent assay). Results:ExperimentⅠ lncRNA FOXF1-AS1, which was expressed in the cytoplasm of astrocytes, combined with kindlin-1.Experiment Ⅱ Compared with C group, MWT was significantly decreased, TWL was shortened at 4 and 7 days after operation, the expression of kindlin-1, Wnt3a and GFAP in spinal cord was up-regulated, and the contents of TNF-α and IL-1β were increased in group NP ( P<0.05). Compared with NP group, MWT was significantly decreased, TWL was shortened at 4 and 7 days after operation, the expression of kindlin-1, Wnt3a and GFAP in spinal cord was up-regulated, and the contents of TNF-α and IL-1β were increased in F group, MWT was increased, TWL was prolonged at 4 and 7 days after operation, and the contents of TNF-α and IL-1β were decreased in group FK and group FW, the expression of kindlin-1, Wnt3a and GFAP was down-regulated in group FK, and the expression of kindlin-1 was up-regulated, and expression of Wnt3a and GFAP was down-regulated in group FW ( P<0.05). Compared with group F, MWT was significantly increased, TWL was prolonged at 4 and 7 days after operation, and the contents of TNF-α and IL-1β were decreased in group FK and group FW, the expression of spinal kindlin-1, Wnt3a and GFAP was down-regulated in group FK, and expression of Wnt3a and GFAP was down-regulated in group FW ( P<0.05). Conclusion:lncRNA FOXF1-AS1 can up-regulate kindlin-1 expression, activate Wnt3a signaling pathway, promote astrocyte activation, and then regulate inflammatory responses and is involved in the process of neuropathic pain in rats.

Evaluation of Kindlin-1 and Ki-67 immunohistochemical expression in primary cutaneous malignant melanoma: a clinical series

Background: The capacity for prognostic prediction of cutaneous melanoma, one of the most aggressive cancers, is still difficult due to the tumor heterogeneity and lack of reliable tumor markers. The objective of this study is to correlate, through immunohistochemistry, a Ki-67 and Kindlin-1 staining in malignant melanomas with the prognosis of the disease. Methods: A historical cohort study. Immunohistochemistry, using mouse anti-human Kindlin-1 and Ki-67 monoclonal antibodies, was performed using tissue blocks from primary cutaneous melanoma patients treated between 2006 and 2014 at our institution. Information regarding pathological data and outcomes were retrieved from medical records. Statistical analyses were conducted in SPSS version 18.0. Results: Thirty patients were included. The median age was from 50.93 ± 15.31 years old. The expression of Ki-67 was detected in all patients with primary cutaneous melanoma, while Kindlin-1 was negative in two. Kindlin expression was not significantly correlated with Ki-67 expression by Spearman's rank correlation analysis (P = 0.46), as well as the expression of both markers and the clinical stage (P = 0.34 and 0.18, respectively). Breslow, Clark and mitotic rate were significantly correlated with AJCC stage (P = 0.001). Conclusion: Other studies investigating clinical evolution are needed to further test the potential of these markers as possible prognostic markers (AU)

Kindlin-2 promotes gallbladder cancer metastasis and invasion by inducing epithelial-mesenchymal transition / 中华外科杂志

Objective@#To investigate the effects of Kindlin-2 on malignant phenotypes of human gallbladder cancer cells and discuss the mechanisms.@*Methods@#The expression level of Kindlin-2 in 30 cases of gallbladder cancer tissues and adjacent non-tumoral tissues collected from the First Affiliated Hospital of Zhengzhou University between September 2012 and May 2013 was assessed by real-time PCR and immunohistochemistry.Lentivirus-mediated Kindlin-2 overexpression was used in gallbladder cancer cell lines GBC-SD and SGC-996.Transwell assay and adhesion assay were investigated to explore the functional role of Kindlin-2 on gallbladder cancer cells.Western Blot was used to test the protein change of epithelial-mesenchymal transition(EMT) characteristics. The t-test was used to analyzed results.@*Results@#The RNA and protein levels of Kindlin-2 in gallbladder cancer tissues were higher than in the non-tumoral tissues (t=4.372, P=0.001; t=7.477, P=0.000). The expression level of Kindlin-2 in gallbladder cancer tissues was correlated with Nevin stage(χ2=5.932, P=0.035). Compared with control groups, the cell-matrix adhesion ability of GBC-SD and SGC-996 with Kindlin-2 overexpression was obviously promoted(1.66±0.03 vs. 1.07±0.22, t=2.710, P=0.041; 2.66±0.24 vs. 1.03±0.02, t=6.610, P=0.020). The number of GBC-SD and SGC-996 cells with Kindlin-2 overexpression passing through the Transwell chamber matrix increased significantly compared with the control groups(116.1±13.9 vs. 54.7±8.4, t=3.781, P=0.019; 136.3±7.5 vs. 64.3±6.4, t=7.302, P=0.002). The wound healing rate of GBC-SD with Kindlin-2 overexpression at 12-hour and 24-hour was higher than that of the group ((42.9±2.2)% vs. (29.7±1.7)%, t=4.690, P=0.009; (65.0±2.4)% vs.(40.4±2.0)%, t=7.945, P=0.001). The wound healing rate of SGC-996 with Kindlin-2 overexpression at 12-hour and 24-hour was also higher than that of the group ((32.9±1.3)% vs. (24.1±1.5)%, t=4.518, P=0.011; (51.3±1.1)% vs. (39.2±1.1)%, t=8.001, P=0.001). The characteristics of EMT were induced in gallbladder cancer cells with Kindlin-2 overexpression, including the up-regulation of N-cadherin, Vemintin and the down-regulation of E-cadherin.@*Conclusion@#The expression of Kindlin-2 is up-regulated in gallbladder cancer tissues and Kindlin-2 promoted the malignant phenotypes of gallbladder cancer cells partially by epithelial-mesenchymal transition.