LIM Domain Protein Research Articles

Role of four and a half LIM domain protein 1 in tumors (Review).

As a cytoskeletal protein, the four and a half LIM domain protein 1 (FHL1) is widely expressed in various cells, particularly skeletal and cardiac muscle cells. FHL1 is involved in the development of the skeletal muscle and myocardium, regulations of gene transcription and thyroid function, and other physiological processes. Its expression is closely related to numerous diseases, such as skeletal muscle disease and viral infections. With the advances in research, the role of FHL1 in the development of tumors is also being revealed. The mechanism of FHL1 in the regulation of tumor growth is complex and is becoming a research focus. It is also expected to become a potential target for tumor therapy. Therefore, the present article reviewed the progress in research on the role of FHL1 in cancer.

Unlocking the secrets of Cardiac development and function: the critical role of FHL2.

FHL2 (Four-and-a-half LIM domain protein 2) is a crucial factor involved in cardiac morphogenesis, the process by which the heart develops its complex structure. It is expressed in various tissues during embryonic development, including the developing heart, and has been shown to play important roles in cell proliferation, differentiation, and migration. FHL2 interacts with multiple proteins to regulate cardiac development as a coactivator or a corepressor. It is involved in cardiac specification and determination of cell fate, cardiomyocyte growth, cardiac remodeling, myofibrillogenesis, and the regulation of HERG channels. Targeting FHL2 has therapeutic implications as it could improve cardiac function, control arrhythmias, alleviate heart failure, and maintain cardiac integrity in various pathological conditions. The identification of FHL2 as a signature gene in atrial fibrillation suggests its potential as a diagnostic marker and therapeutic target for this common arrhythmia.

FHL2 expression by cancer-associated fibroblasts promotes metastasis and angiogenesis in lung adenocarcinoma.

Cancer-associated fibroblasts (CAFs) contribute to the progression of lung cancer. Four and a half LIM domain protein-2 (FHL2) is a component of focal adhesion structures. We analyzed the function of FHL2 expressed by CAFs in lung adenocarcinoma. Expression of FHL2 in fibroblast subtypes was investigated using database of single-cell RNA-sequencing of lung cancer tissue. The role of FHL2 in the proliferation and migration of CAFs was assessed. The effects of FHL2 knockout on the migration and invasion of human lung adenocarcinoma cells and tube formation of endothelial cells induced by CAF-conditioned medium (CM) were evaluated. The effect of FHL2 knockout in CAFs on metastasis was determined using a murine orthotopic lung cancer model. The prognostic significance of stromal FHL2 was assessed by immunohistochemistry in human adenocarcinoma specimens. FHL2 is highly expressed in myofibroblasts in cancer tissue. TGF-β1 upregulated FHL2 expression in CAFs and FHL2 knockdown attenuated CAF proliferation. FHL2 knockout reduced CAF induced migration of A110L and H23 human lung adenocarcinoma cell lines, and the induction of tube formation of endothelial cells. FHL2 knockout reduced CAF-induced metastasis of lung adenocarcinomas in an orthotopic model in vivo. The concentration of Osteopontin (OPN) in CM from CAF was downregulated by FHL2 knockout. siRNA silencing and antibody blocking of OPN reduced the pro-migratory effect of CM from CAF on lung cancer cells. In resected lung adenocarcinoma specimens, positive stromal FHL2 expression was significantly associated with higher microvascular density and worse prognosis. In conclusion, FHL2 expression by CAFs enhances the progression of lung adenocarcinoma by promoting angiogenesis and metastasis.

Isoforms of the cytoskeletal lim-domain protein zyxin in the early embryogenesis of <i>Xenopus laevis</i>

Zyxin is a conserved mechanosensitive LIM-domain protein that regulates the assembly of F-actin filaments at cell junctions. At the same time, under mechanical stress, it can move from focal adhesions to stress fibrils and into the nucleus and affect gene expression. In Xenopus laevis embryonic cells, western blots with antibodies against Zyxin’s N-terminal and C-terminal LIM-domain regions revealed two full-length and two short isoforms. The intracellular localization of these isoforms and the number depending on the stage of embryo development were determined. According to our study, full forms with different electrophoretic mobility are localized differently in the cell, and the shortest isoform containing LIM-domains is stable during development, mainly located in the nucleus, and participates in gene expression regulation. This study may be of great value to understanding how the LIM-domain mechanotransducer proteins jointly influence morphogenesis and differentiation in vertebrates at early stages of development.

Reversion induced LIM domain protein (RIL) is a Daam1-interacting protein and regulator of the actin cytoskeleton during non-canonical Wnt signaling

The Daam1 protein regulates Wnt-induced cytoskeletal changes during vertebrate gastrulation though its full mode of action and binding partners remain unresolved. Here we identify Reversion Induced LIM domain protein (RIL) as a new interacting protein of Daam1. Interaction studies uncover binding of RIL to the C-terminal actin-nucleating portion of Daam1 in a Wnt-responsive manner. Immunofluorescence studies showed subcellular localization of RIL to actin fibers and co-localization with Daam1 at the plasma membrane. RIL gain- and loss-of-function approaches in Xenopus produced severe gastrulation defects in injected embryos. Additionally, a simultaneous loss of Daam1 and RIL synergized to produce severe gastrulation defects indicating RIL and Daam1 may function in the same signaling pathway. RIL further synergizes with another novel Daam1-interacting protein, Formin Binding Protein 1 (FNBP1), to regulate gastrulation. Our studies altogether show RIL mediates Daam1-regulated non-canonical Wnt signaling that is required for vertebrate gastrulation.

Glial growth factor 2 treatment alleviates ischemia and reperfusion-damaged integrity of the blood-brain barrier through decreasing Mfsd2a/caveolin-1-mediated transcellular and Pdlim5/YAP/TAZ-mediated paracellular permeability.

The impairment of blood-brain barrier (BBB) integrity is the pathological basis of hemorrhage transformation and vasogenic edema following thrombolysis and endovascular therapy. There is no approved drug in the clinic to reduce BBB damage after acute ischemic stroke (AIS). Glial growth factor 2 (GGF2), a recombinant version of neuregulin-1β that can stimulates glial cell proliferation and differentiation, has been shown to alleviate free radical release from activated microglial cells. We previously found that activated microglia and proinflammatory factors could disrupt BBB after AIS. In this study we investigated the effects of GGF2 on AIS-induced BBB damage as well as the underlying mechanisms. Mouse middle cerebral artery occlusion model was established: mice received a 90-min ischemia and 22.5 h reperfusion (I/R), and were treated with GGF2 (2.5, 12.5, 50 ng/kg, i.v.) before the reperfusion. We showed that GGF2 treatment dose-dependently decreased I/R-induced BBB damage detected by Evans blue (EB) and immunoglobulin G (IgG) leakage, and tight junction protein occludin degradation. In addition, we found that GGF2 dose-dependently reversed AIS-induced upregulation of vesicular transcytosis increase, caveolin-1 (Cav-1) as well as downregulation of major facilitator superfamily domain containing 2a (Mfsd2a). Moreover, GGF2 decreased I/R-induced upregulation of PDZ and LIM domain protein 5 (Pdlim5), an adaptor protein that played an important role in BBB damage after AIS. In addition, GGF2 significantly alleviated I/R-induced reduction of YAP and TAZ, microglial cell activation and upregulation of inflammatory factors. Together, these results demonstrate that GGF2 treatment alleviates the I/R-compromised integrity of BBB by inhibiting Mfsd2a/Cav-1-mediated transcellular permeability and Pdlim5/YAP/TAZ-mediated paracellular permeability.

The effect of programmed resistance training on the muscle myofibrillar proteome

Resistance training increases muscle size but little is known about the dynamic processes that underpin the gains in muscle mass. We investigated rat muscle during 30 days of unilateral programmed resistance training (PRT) using the stable isotope (deuterium oxide; D2O) in vivo and proteomics. Three-month-old, male Wistar rats (body weight 348 ± 20 g) were assigned to four groups (n = 4, in each), including a control group and experimental groups that received D2O for 10, 20 or 30 days. Under ethically approved procedures, deuterium was administered, and a stimulating device was surgically implanted to activate the left peroneal nerve and cause maximal contraction of the dorsiflexors (inc. tibialis anterior; TA) and partial contraction of the plantar flexors. PRT consisted of 1 bout per day of 5 sets of 10 repetitions (1 repetition consisted of 2 s stimulation at 100 Hz with 2 s rest between repetitions and 2.5 min between sets). One hour after the final training bout (i.e. day 10, 20, or 30) animals were killed and the left (stimulated) and right (contralateral control) TA were extracted and weighed. Muscles were fractionated into myofibrillar and sarcoplasmic components. Protein content was calculated via Bradford assay and proteomic analysis of myofibrillar proteins was conducted via liquid chromatography-tandem mass spectrometry of peptide digests. Statistical analysis was conducted using R (v4.3.2.) and functional annotation was performed using the STRING database. Two-way mixed ANOVA was used to investigate differences between condition (stimulated vs contralateral control) and time (0, 10, 20, or 30 days). The protein content of stimulated TA increased (P < 0.05) from 0.579 ± 0.05 mg at day zero to 1.096 ± 0.15 mg after 30 days of PRT, whereas the protein content of control TA (0.618 ± 0.04 mg) was consistent across the 30-day experimental period. Proteomic analysis encompassed 244 proteins and the abundance of 45 proteins exhibited a significant (P < 0.05) interaction between condition and time. Stimulated muscle was enriched in mitochondrial enzymes. For example, the beta-subunit of ATPase synthase (ATPB) increased from 14.6 ± 4.5 to 74 ± 15.6 μg in stimulated TA and was 17 ± 5 in control TA. PRT also increased the abundance of neonatal myosin heavy chain (MYH8), four-and-a-half LIM domains protein 1 (FHL1) and muscular LMNA interacting protein (MLIP). These findings suggest the energy requirements of daily PRT are met by mitochondrial metabolism and PRT may be associated with activation of the muscle developmental programme.

OGA mutant aberrantly hydrolyzes O-GlcNAc modification from PDLIM7 to modulate p53 and cytoskeleton in promoting cancer cell malignancy

O-GlcNAcase (OGA) is the only human enzyme that catalyzes the hydrolysis (deglycosylation) of O-linked beta-N-acetylglucosaminylation (O-GlcNAcylation) from numerous protein substrates. OGA has broad implications in many challenging diseases including cancer. However, its role in cell malignancy remains mostly unclear. Here, we report that a cancer-derived point mutation on the OGA's noncatalytic stalk domain aberrantly modulates OGA interactome and substrate deglycosylation toward a specific set of proteins. Interestingly, our quantitative proteomic studies uncovered that the OGA stalk domain mutant preferentially deglycosylated protein substrates with +2 proline in the sequence relative to the O-GlcNAcylation site. One of the most dysregulated substrates is PDZ and LIM domain protein 7 (PDLIM7), which is associated with the tumor suppressor p53. We found that the aberrantly deglycosylated PDLIM7 suppressed p53 gene expression and accelerated p53 protein degradation by promoting the complex formation with E3 ubiquitin ligase MDM2. Moreover, deglycosylated PDLIM7 significantly up-regulated the actin-rich membrane protrusions on the cell surface, augmenting the cancer cell motility and aggressiveness. These findings revealed an important but previously unappreciated role of OGA's stalk domain in protein substrate recognition and functional modulation during malignant cell progression.

Proximal tubular FHL2, a novel downstream target of hypoxia inducible factor 1, is a protector against ischemic acute kidney injury

Four-and-a-half LIM domains protein 2 (FHL2) is an adaptor protein that may interact with hypoxia inducible factor 1α (HIF-1α) or β-catenin, two pivotal protective signaling in acute kidney injury (AKI). However, little is known about the regulation and function of FHL2 during AKI. We found that FHL2 was induced in renal tubular cells in patients with acute tubular necrosis and mice model of ischemia-reperfusion injury (IRI). In cultured renal proximal tubular cells (PTCs), hypoxia induced FHL2 expression and promoted the binding of HIF-1 to FHL2 promoter. Compared with control littermates, mice with PTC-specific deletion of FHL2 gene displayed worse renal function, more severe morphologic lesion, more tubular cell death and less cell proliferation, accompanying by downregulation of AQP1 and Na, K-ATPase after IRI. Consistently, loss of FHL2 in PTCs restricted activation of HIF-1 and β-catenin signaling simultaneously, leading to attenuation of glycolysis, upregulation of apoptosis-related proteins and downregulation of proliferation-related proteins during IRI. In vitro, knockdown of FHL2 suppressed hypoxia-induced activation of HIF-1α and β-catenin signaling pathways. Overexpression of FHL2 induced physical interactions between FHL2 and HIF-1α, β-catenin, GSK-3β or p300, and the combination of these interactions favored the stabilization and nuclear translocation of HIF-1α and β-catenin, enhancing their mediated gene transcription. Collectively, these findings identify FHL2 as a direct downstream target gene of HIF-1 signaling and demonstrate that FHL2 could play a critical role in protecting against ischemic AKI by promoting the activation of HIF-1 and β-catenin signaling through the interactions with its multiple protein partners.

Structural domain in the Titin N2B-us region binds to FHL2 in a force-activation dependent manner

Titin N2B unique sequence (N2B-us) is a 572 amino acid sequence that acts as an elastic spring to regulate muscle passive elasticity. It is thought to lack stable tertiary structures and is a force-bearing region that is regulated by mechanical stretching. In this study, the conformation of N2B-us and its interaction with four-and-a-half LIM domain protein 2 (FHL2) are investigated using AlphaFold2 predictions and single-molecule experimental validation. Surprisingly, a stable alpha/beta structural domain is predicted and confirmed in N2B-us that can be mechanically unfolded at forces of a few piconewtons. Additionally, more than twenty FHL2 LIM domain binding sites are predicted to spread throughout N2B-us. Single-molecule manipulation experiments reveals the force-dependent binding of FHL2 to the N2B-us structural domain. These findings provide insights into the mechano-sensing functions of N2B-us and its interactions with FHL2.

LncRNA PAARH impacts liver cancer cell proliferation by engaging miR‑6512‑3p to target LASP1.

Long non-coding (lnc)RNAs serve a pivotal role as regulatory factors in carcinogenesis. The present study aimed to assess the involvement of the lncRNA progression and angiogenesis-associated RNA in hepatocellular carcinoma (PAARH) in liver cancer, along with the associated underlying mechanism. Through the use of reverse transcription-quantitative (RT-q)PCR, differences in the expression levels of PAARH in HepG2, HEP3B2.1.7, HCCLM3, Huh-7 and MHCC97-H liver cancer cell lines and THLE-2 epithelial cell lines were evaluated. The liver cancer cell line with the greatest, significantly different, level of expression relative to the normal liver cell line was selected for subsequent experiments. Using ENCORI database, the putative target genes of the microRNA (miR) miR-6512-3p were predicted. Cells were then transfected with lentiviruses carrying short-hairpin-PAARH to interfere with PAARH expression. Subsequently, HepG2 liver cancer cells were transfected with a miR-6512-3p mimic and an inhibitor, and the expression levels of miR-6512-3p and the LIM and SH3 domain protein 1 (LASP1) in cells were assessed using RT-qPCR analysis. Cell proliferation was subsequently evaluated using colony formation assays, and immunofluorescence and western blotting were used to assess the expression level of LASP1 in transfected cells. The binding interaction between miR-6512-3p and LASP1 was further evaluated using a dual-luciferase reporter gene assay. Liver cancer cells were found to exhibit higher expression levels of PAARH compared with normal liver cells. Following PAARH interference, the expression level of miR-6512-3p was significantly increased, whereas that of LASP1 was significantly decreased, resulting in a reduction in cell proliferation. In liver cancer cells, miR-6512-3p overexpression led to a significant reduction in the LASP1 level and reduced proliferation, whereas suppressing miR-6512-3p led to a significant increase in LASP1 levels and increased proliferation. Additionally, the inhibition of miR-6512-3p caused the states of low LASP1 expression and reduced cell proliferation to be reversed. LASP1, a recently identified target gene of miR-6512-3p, was demonstrated to be suppressed by miR-6512-3p overexpression, thereby inhibiting liver cancer cell proliferation. Taken together, the findings of the present study demonstrate that the lncRNA PAARH may enhance liver cancer cell proliferation by engaging miR-6512-3p to target LASP1.

HIF-1α and adaptor protein LIM and senescent cell antigen-like domains protein 1 axis promotes tubulointerstitial fibrosis by interacting with vimentin in angiotensin II-induced hypertension.

Activation of the renin-angiotensin system, as a hallmark of hypertension and chronic kidney diseases (CKD) is the key pathophysiological factor contributing to the progression of tubulointerstitial fibrosis. LIM and senescent cell antigen-like domains protein 1 (LIMS1) plays an essential role in controlling of cell behaviour through the formation of complexes with other proteins. Here, the function and regulation of LIMS1 in angiotensin II (Ang II)-induced hypertension and tubulointerstitial fibrosis was investigated. C57BL/6 mice were treated with Ang II to induce tubulointerstitial fibrosis. Hypoxia-inducible factor-1α (HIF-1α) renal tubular-specific knockout mice or LIMS1 knockdown AAV was used to investigate their effects on Ang II-induced renal interstitial fibrosis. In vitro, HIF-1α or LIMS1 was knocked down or overexpressed in HK2 cells after exposure to Ang II. Increased expression of tubular LIMS1 was observed in human kidney with hypertensive nephropathy and in murine kidney from Ang II-induced hypertension model. Tubular-specific knockdown of LIMS1 ameliorated Ang II-induced tubulointerstitial fibrosis in mice. Furthermore, we demonstrated that LIMS1 was transcriptionally regulated by HIF-1α in tubular cells and that tubular HIF-1α knockout ameliorates LIMS1-mediated tubulointerstitial fibrosis. In addition, LIMS1 promotes Ang II-induced tubulointerstitial fibrosis by interacting with vimentin. We conclude that HIF-1α transcriptionally regulated LIMS1 plays a central role in Ang II-induced tubulointerstitial fibrosis through interacting with vimentin. Our finding represents a new insight into the mechanism of Ang II-induced tubulointerstitial fibrosis and provides a novel therapeutic target for progression of CKD.

MiR-3682-3p promotes esophageal cancer progression by targeting FHL1 and activating the Wnt/β-catenin signaling pathway

BackgroundEsophageal cancer (EC) is highly ranked among all cancers in terms of its incidence and mortality rates. MicroRNAs (miRNAs) are considered to play key regulatory parts in EC. Multiple research studies have indicated the involvement of miR-3682-3p and four and a half LIM domain protein 1 (FHL1) in the achievement of tumors. The aim of this research was to clarify the significance of these genes and their possible molecular mechanism in EC. MethodsData from a database and the tissue microarray were made to analyze the expression and clinical significance of miR-3682-3p or FHL1 in EC. Reverse transcription quantitative PCR and Western blotting were used to detect the expression levels of miR-3682-3p and FHL1 in EC cells. CCK8, EdU, wound healing, Transwell, flow cytometry, and Western blotting assays were performed to ascertain the biological roles of miR-3682-3p and FHL1 in EC cells. To confirm the impact of miR-3682-3p in vivo, a subcutaneous tumor model was created in nude mice. The direct interaction between miR-3682-3p and FHL1 was demonstrated through a luciferase assay, and the western blotting technique was employed to assess the levels of crucial proteins within the Wnt/β-catenin pathway. ResultsThe noticeable increase in the expression of miR-3682-3p and the decrease in the expression of FHL1 were observed, which correlated with a negative impact on the patients' overall survival. Upregulation of miR-3682-3p expression promoted the growth and metastasis of EC, while overexpression of FHL1 partially reversed these effects. Finally, miR-3682-3p motivates the Wnt/β-catenin signal transduction by directly targeting FHL1. ConclusionMiR-3682-3p along the FHL1 axis activated the Wnt/β-catenin signaling pathway and thus promoted EC malignancy.

Abstract 5201: Characterization of PDLIM2 in non-small cell lung cancer

Abstract Introduction: PDZ and LIM domain protein 2 (PDLIM2) acts as tumor suppressor by downregulating NF-κB and STAT3 signaling, modulating inflammation, immune response, and cell survival. Mouse model studies have demonstrated that downregulation of PDLIM2 leads to PD-1 immune blockade and chemotherapy resistance. We present a large clinical and molecular characterization of PDLIM2 expression in non-small cell lung cancer (NSCLC). Methods: NextGen sequencing of DNA (whole exome)/RNA (whole transcriptome) was performed for NSCLC (Total N = 29126; Adenocarcinoma [-A, N = 15765], Squamous [-S, N = 6416]) patient tumors submitted to Caris Life Sciences (Phoenix, AZ). Mutations were defined as pathogenic SNVs/indels. Samples were stratified by PDLIM2 expression quartiles (in transcripts per million [TPM]) for all NSCLC tumors (Q4: H, Q1: L). PD-L1 expression [22C3; Positive (+): tumor proportion score (TPS) ≥1%]was assessed by IHC. High tumor mutational burden (TMB-high) set as ≥10 mutations per Mb. Cell infiltration in the tumor microenvironment was estimated by QuantiSEQ. Gene expression profiles were analyzed for transcriptional signatures predictive of response to immunotherapy (T cell-inflamed). Real-world overall survival was assessed from insurance claims data and Kaplan-Meier estimates were calculated for molecularly defined subpopulations. Mann-Whitney U and X2/Fisher-Exact tests were applied where appropriate, with P-values adjusted for multiple comparisons (p < 0.05). Results: Median PDLIM2 expression was higher in NSCLC-A compared to NSCLC-S (15.3 vs 13.6 TPM, p < 0.001). PDLIM2-AL had a lower prevalence of EGFR mutations than PDLIM2-AH (15.5% vs 19.4%, p < 0.01), but the opposite pattern was observed for STK11 (21.5% vs 11.2%), RB1 (7.5% vs 3.8%), TP53 (62.9% vs 52.8%), KEAP1 (18.4% vs 10.9%), and SMARCA4 (9.15 vs 4.5%) alterations (all p < 0.001). PDLIM2-AL tumors had decreased PD-L1+ (L: 52.4% vs H: 58.4% p < 0.001) but increased TMB-High status (L: 40.9% vs H: 28.5%, p < 0.001). PD-L1+ and TMB-H frequency did not vary with PDLIM2 expression in NSCLC-S. In both NSCLC-A and -S tumors, PDLIM2H had increased infiltration of NK cells, macrophages, dendritic cells, T cells, neutrophils, monocytes, and B cells compared to PDLIM2L (all p < 0.05), in addition to increased T cell-inflammed scores (p < 0.001). PDLIM2-AH was associated with improved overall survival (OS) (median 21.7 vs L: 15.6 months; p < 0.001; Hazard ratio [HR] = 0.825, 95% Confidence Interval [CI] 0.765 - 0.889) and time on pembrolizumab treatment (median 6.2 vs L: 5.6 months; p = 0.009; HR = 0.825 95% CI 0.714 - 0.953). No difference in OS was observed between PDLIM2-SH vs L tumors (H: 14.8 vs L: 14.0 months; p = 0.37; HR = 0.95, CI 0.85-1.06). Conclusions: NSCLC-A with high PDLIM2 expression have a unique mutational profile, increased immune cell infiltration and favorable OS. Therapeutic strategies for targeting PDLIM2 to modulate NF-κB and STAT3 signaling should be further explored. Citation Format: Karam Ashouri, Harris Krause, Andrew Elliott, Stephen V. Liu, Patrick C. Ma, Balazs Halmos, Zhaoxia Qu, Gutian Xiao, Ari Vanderwalde, Jorge J. Nieva. Characterization of PDLIM2 in non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5201.

The ability of the LIMD1 and TRIP6 LIM domains to bind strained f-actin is critical for their tension dependent localization to adherens junctions and association with the Hippo pathway kinase LATS1.

A key step in regulation of Hippo pathway signaling in response to mechanical tension is recruitment of the LIM domain proteins TRIP6 and LIMD1 to adherens junctions. Mechanical tension also triggers TRIP6 and LIMD1 to bind and inhibit the Hippo pathway kinase LATS1. How TRIP6 and LIMD1 are recruited to adherens junctions in response to tension is not clear, but previous studies suggested that they could be regulated by the known mechanosensory proteins α-catenin and vinculin at adherens junctions. We found that the three LIM domains of TRIP6 and LIMD1 are necessary and sufficient for tension-dependent localization to adherens junctions. The LIM domains of TRIP6, LIMD1, and certain other LIM domain proteins have been shown to bind to actin networks under strain/tension. Consistent with this, we show that TRIP6 and LIMD1 colocalize with the ends of actin fibers at adherens junctions. Point mutations in a key conserved residue in each LIM domain that are predicted to impair binding to f-actin under strain inhibits TRIP6 and LIMD1 localization to adherens junctions and their ability to bind to and recruit LATS1 to adherens junctions. Together these results show that the ability of TRIP6 and LIMD1 to bind to strained actin underlies their ability to localize to adherens junctions and regulate LATS1 in response to mechanical tension.

Decreased PDLIM1 expression in endothelial cells contributes to the development of intracranial aneurysm.

Intracranial aneurysm (IA) is a common vascular enlargement that occurs in the wall of cerebral vessels and frequently leads to fatal subarachnoid hemorrhage. PDZ and LIM domain protein 1 (PDLIM1) is a cytoskeletal protein that functions as a platform for multiple protein complex formation. However, whether PDLIM is involved in the pathogenesis of IA remains poorly understood. Loss-of-function and gain-of-function strategies were employed to determine the in vitro roles of PDLIM1 in vascular endothelial cells (VECs). A rat model of IA was generated to study the role of PDLIM1 in vivo. Gene expression profiling, Western blotting, and dual luciferase reporter assays were performed to uncover the underlying cellular mechanism. Clinical IA samples were used to determine the expression of PDLIM1 and its downstream signaling molecules. PDLIM1 expression was reduced in the endothelial cells of IA and was regulated by Yes-associated protein 1 (YAP1). Genetic silencing of PDLIM1 inhibited the viability, migratory ability, and tube formation ability of VECs. Opposite results were obtained by ectopic expression of PDLIM1. Additionally, PDLIM1 overexpression mitigated IA in vivo. Mechanistic investigations revealed that PDLIM1 promoted the transcriptional activity of β-catenin and induced the expression of v-myc myelocytomatosis viral oncogene homolog (MYC) and cyclin D1 (CCND1). In clinical settings, reduced expression of PDLIM1 and β-catenin downstream target genes was observed in human IA samples. Our study indicates that YAP1-dependent expression of PDLIM1 can inhibit IA development by modulating the activity of the Wnt/β-catenin signaling pathway and that PDLIM1 deficiency in VECs may represent a potential marker of aggressive disease.

Promotion of non-small cell lung cancer tumor growth by FHL2 via inducing angiogenesis and vascular permeability.

Antiangiogenetic therapy is one of the effective strategies for non-small cell lung cancer (NSCLC) treatment. Four-and-a-half LIM-domain protein 2 (FHL2) serves as a key function in cell growth and metastasis of multiple cancers, but the role of FHL2 in NSCLC angiogenesis has not been intensely examined. FHL2 expression in NSCLC tissues and cell lines and its correlation with patients prognosis were investigated by using The Cancer Genome Atlas (TCGA) database and quantitative polymerase chain reaction (qPCR). Cell Counting Kit-8 (CCK-8) assay, EdU (5-ethynyl-2'-deoxyuridine) assay, and a xenograft model were used to investigate the effects of FHL2 on NSCLC progression in vitro and in vivo. CCK-8, wound-healing, Transwell invasion, tube formation, and permeability assays were performed to determine the roles of FHL2 in angiogenesis and vascular permeability. Vascular endothelial growth factor A (VEGFA) enzyme-linked immunosorbent assay (ELISA) assay, Western blot analysis, and MK-2206 were used to investigate the specific mechanism mediated by FHL2. We demonstrated that FHL2 was significantly upregulated in NSCLC tissues and cell lines and was associated with poor prognosis. FHL2 overexpression enhanced the cell viability of NSCLC cells, as well as the proliferation, migration, invasion, and tube formation of human umbilical vein endothelial cells (HUVECs). In addition, we determined that FHL2 activated the AKT-mTOR signaling pathway in HUVECs by promoting VEGFA secretion from NSCLC cells, thereby inducing angiogenesis and vascular leakiness. We further confirmed that FHL2 also promoted NSCLC tumor growth in vivo. Our study revealed the role of FHL2 in NSCLC and the mechanism by which FHL2 promotes NSCLC tumorigenesis, providing novel insights into targeted therapy for NSCLC.

ABLIM1, a novel ubiquitin E3 ligase, promotes growth and metastasis of colorectal cancer through targeting IĸBα ubiquitination and activating NF-ĸB signaling

Actin-binding LIM protein 1 (ABLIM1), a member of the LIM-domain protein family, has been reported as a suppressor in several tumors whereas its role in colorectal cancer (CRC) remains unknown. In this study, we find that ABLIM1 is up-regulated in CRC patients and high levels of ABLIM1 predict short disease-free survival time. Knock-down of ABLIM1 in CRC cell lines by lenti-virus leads to inhibited cell proliferation, migration, and invasion capabilities in vitro and impaired growth of tumor xenografts and liver metastasis lesions in vivo, while ABLIM1 overexpression accelerates tumor growth and invasion in vitro. Mechanistically, we uncover that ABLIM1 activates the NF-ĸB/CCL-20 signaling through modulating IĸBα ubiquitination and proteasomal-mediated degradation. Further co-immunoprecipitation, in vivo and in vitro ubiquitination assays reveal ABLIM1 as a novel ubiquitin E3 ligase binding to IĸBα. Interestingly, The E3 ligase catalysis activity of ABLIM1 depends on its 402–778aa rather than its LIM domains and its interaction with IĸBα relies on the HP domain. Our findings delineate the oncogenic role of ABLIM1 in CRC progression and reveal it as a novel E3 ligase targeting IĸBα, providing new insights into the regulation of NF-ĸB signaling in tumors.

Derivation of two human induced pluripotent stem cell lines carrying a missense mutation in FHL1 (c.377G > A, p.C126Y) linked to familial muscular dystrophy

FHL1 gene locates in the Xq26 region and encodes for four and half LIM domain protein 1. It plays a crucial role in muscle cells and mutations in FHL1 are related to muscular dystrophy (MD). Peripheral blood mononuclear cells (PBMCs) were obtained from 2 family patients with MD that carry a pathogenic missense mutation in FHL1 (c.377G > A, p.C126Y). Induced pluripotent stem cells (iPSCs) were generated by PBMCs reprogramming using the lentiviral-hSTEMCCA-loxP vector, obtaining FHL1-T and FHL1-V iPSCs lines from patients. FHL1 genotype was maintained, and stemness and pluripotency were confirmed in both iPSCs lines.

Development and validation of a prognostic nomogram based on the hub genes of patients with hypertensive intracerebral hemorrhage.

Hypertensive intracerebral hemorrhage (HICH) is frequently associated with high disability, high mortality, and poor prognosis. The present study aimed to identify genes associated with HICH to construct prognostic models to improve accuracy in predicting HICH prognosis. Hub genes were identified by screening out differentially expressed genes from data in the Gene Expression Omnibus database and conducting weighted gene co-expression network analysis. 68 patients with HICH were recruited and categorized based on prognosis. The univariate logistic, least absolute shrinkage and selection operator, and multivariate logistic regression models were then established based on clinical data and the identified hub genes. A prognostic model was constructed based on the nomogram score. The model was validated using receiver operating characteristic curve, C-index, calibration plots, and decision curve analysis. It was also compared to a prognostic model constructed based on clinical data alone. The prognostic value of the nomogram score was assessed in different subgroups. Three hub genes: pro-platelet basic protein (PPBP), PDZ and LIM domain protein 1 (PDLIM1), and metalloproteinase 1 (TIMP1) were identified as significantly correlated to adverse outcomes in HICH. These hub genes, in combination with the clinical data, were used to construct a nomogram score system, which exhibited strong predictive power, excellent consistency between actual outcomes and predictions, and a higher net clinical benefit. HICH patients with high scores presented significantly worse outcome. Importantly, the developed nomogram score system was superior to the use of clinicopathological features in predicting HICH prognosis. The nomogram score system exhibited adequate predictive performance in different subgroups as well. The nomogram score system based on PPBP, PDLIM1, and TIMP1 genes, along with clinical data, exhibited superior performance in predicting adverse outcome in HICH patients. This system could, therefore, be useful for guiding clinical decisions and providing valuable insight for designing individualized treatments for HICH patients.