Kindlin-2 Modulates the Survival, Differentiation, and Migration of Induced Pluripotent Cell-Derived Mesenchymal Stromal Cells

Mesenchymal stromal cells promote the formation of lung cancer organoids via Kindlin-2

BACKGROUND

Patient-derived lung cancer organoids (PD-LCOs) demonstrate exceptional potential in preclinical testing and serve as a promising model for the multimodal management of lung cancer. However, certain lung cancer cells derived from patients exhibit limited capacity to generate organoids due to inter-tumor or intra-tumor variability. To overcome this limitation, we have created an in vitro system that employs mesenchymal stromal cells (MSCs) or fibroblasts to serve as a supportive scaffold for lung cancer cells that do not form organoids.

METHODS

We successfully established an MSCs/fibroblast co-culture system to form LCOs. We analyzed the morphological and histological similarities between LCOs co-cultured with fibroblast and primary lung cancer lesions through HE and IF staining. We evaluated whether LCOs co-cultured with fibroblast retained the original genetic mutations of their source tumors based on WES. RNA sequencing was used to analyze the differences in gene expression profiles between LCOs co-cultured with fibroblast and paracancerous organoids (POs). Importantly, we have successfully validated the impact of Kindlin-2 on the regulation of MSCs in organoid formation through lentiviral vector-mediated interference or overexpression of kindlin-2.

RESULTS

Our findings demonstrate that the addition of MSCs/fibroblasts to three tumor samples, initially incapable of forming organoids by traditional methods, successfully facilitated the cultivation of tumor organoids. Importantly, these organoids co-cultured with fibroblast faithfully recapitulate the tissue morphology of original lung tumors and replicate the genetic profile observed in the parental tumors even after prolonged in vitro culture. Moreover, drug responses exhibited by these organoids co-cultured with MSCs/fibroblasts are consistent with those observed in the original tumors. Mechanistically, we have also identified kindlin-2 as a crucial regulator linking extracellular matrix (ECM) and mitochondria that influence MSC/fibroblast-mediated support for tumor organoid formation.

CONCLUSION

The results obtained from our research enhance the understanding of the mechanisms implicated in the formation of tumor organoids and aid in creating stronger patient-specific tumor organoid models. This advancement supports the refinement of personalized drug response assessments for use in clinical settings.

Kindlin-2 regulates colonic cancer stem-like cells survival and self-renewal via Wnt/β-catenin mediated pathway

BACKGROUND

Cancer Stem Cells (CSCs) have emerged as a critical mediator in recurrence and resistance in cancers. Kindlin-isoform (1 and 2) binds with cytoplasmic β-tail of integrin and are essential co-activators of integrin function. Given their important function in regulating cancer hallmarks such as cell proliferation, invasion, migration, and metastasis, we hypothesize that it might play a critical role in CSC growth, survival, and self-renewal of colon cancer.

MATERIALS AND METHODS

Using knockdown approaches, we inhibited Kindlin-2 expression in HCT116 and HT29 colon cancer cells. Extreme limiting dilution and self-renewal assay were performed to measure the role of Kindlin in colonic CSC. Standard methods such as qRT-PCR and western blotting were carried out to understand the signaling cascade by which Kindlin regulates CSC marker expression and downstream targets.

RESULTS

Our data show isoform-specific upregulation of Kindlin-2 in colonic CSCs. The silencing of Kindlin-2 reduces colonosphere formation, decreases CSC size, and self-renewal marker genes such as CD-133, CXCR-4, LGR-5, and C-MYC. Kindlin-2 silencing reduces colonosphere proliferation, invasion, and migration of colonic CSCs. Mechanistically, Kindlin-2 silencing reduces the expression, and nuclear localization of β-catenin, and decreases β-catenin target genes such as C-MYC, cyclin D1, DKK-1, and Snail-1.

CONCLUSION

Our study delineates the isoform-specific activity of Kindlin-2 in regulating Colonic CSC. Isoform-specific targeting of Kindlin-2 may be a novel strategy to tackle this devastating disease.

Opposite roles of Kindlin orthologs in cell survival and proliferation

OBJECTIVE

It is unclear why adhesion-dependent cells such as epithelium undergo anoikis without anchorage, while adhesion-independent blood cells thrive in suspension. The adhesive machinery of these cells is similar, with the exception of Kindlin orthologs, Kindlin 2 (K2) and Kindlin 3 (K3). Here we address how Kindlins control cell survival and proliferation in anchorage-dependent and independent cells.

MATERIAL AND METHODS

To demonstrate the opposite roles of Kindlin's in cell survival we utilized in vivo and in vitro models and K3 and K2 knockdown and knockin cells. We used human lymphocytes from the K3 deficient patients in tumour model, K3 knockout and knockin macrophages and K2 knockout and knockin MEF cells for experiments in under conditions of adhesion and in suspension.

RESULTS

Depletion of K3 promotes cell proliferation and survival of anchorage-independent cells regardless of cell attachment. In contrast, the absence of K2 in anchorage-dependent cells accelerates apoptosis and limits proliferation. K3 deficiency promotes human lymphoma growth and survival in vivo. Kindlins' interaction with paxillin, is critical for their differential roles in cell anchorage. While disruption of K2-paxillin binding leads to increased apoptosis, the lack of K3-paxillin binding has an opposite effect in adhesion-independent cells.

CONCLUSION

Kindlin ortologs and their interaction to cytoskeletal protein paxillin define the mechanisms of anchorage dependence. Our study identifies the key elements of the cell adhesion machinery in cell survival and tumour metastasis, proposing possible targets for tumour treatment.

Kindlin-2 Promotes Chondrogenesis and Ameliorates IL-1beta-Induced Inflammation in Chondrocytes Cocultured with BMSCs in the Direct Contact Coculture System

The osteoarthritis caused by trauma or inflammation is associated with severe patient morbidity and economic burden. Accumulating studies are focusing on the repair of articular cartilage defects by constructing tissue-engineered cartilage. Recent evidence suggests that optimizing the source and quality of seed cells is one of the key points of cartilage tissue engineering. In this study, we demonstrated that Kindlin-2 and its activated PI3K/AKT signaling played an essential role in promoting extracellular matrix (ECM) secretion and ameliorating IL-1beta-induced inflammation in chondrocytes cocultured with bone marrow stem cells (BMSCs). In vivo experiments revealed that coculture significantly promoted hyaline cartilage regeneration. In vitro studies further uncovered that chondrocytes cocultured with BMSCs in the direct contact coculture system upregulated Kindlin-2 expression and subsequently activated the PI3K/AKT signaling pathway, which not only increases Sox9 and Col2 expression but also restores mitochondrial membrane potential and reduces ROS levels and apoptosis under inflammatory conditions. Overall, our findings indicated that direct contact BMSC-chondrocyte coculture system could promote chondrogenesis, and identified Kindlin-2 represents a key regulator in this process.

Application of mesenchymal stem cells derived from human pluripotent stem cells in regenerative medicine

Mesenchymal stem cells (MSCs) represent the most clinically used stem cells in regenerative medicine. However, due to the disadvantages with primary MSCs, such as limited cell proliferative capacity and rarity in the tissues leading to limited MSCs, gradual loss of differentiation during in vitro expansion reducing the efficacy of MSC application, and variation among donors increasing the uncertainty of MSC efficacy, the clinical application of MSCs has been greatly hampered. MSCs derived from human pluripotent stem cells (hPSC-MSCs) can circumvent these problems associated with primary MSCs. Due to the infinite self-renewal of hPSCs and their differentiation potential towards MSCs, hPSC-MSCs are emerging as an attractive alternative for regenerative medicine. This review summarizes the progress on derivation of MSCs from human pluripotent stem cells, disease modelling and drug screening using hPSC-MSCs, and various applications of hPSC-MSCs in regenerative medicine. In the end, the challenges and concerns with hPSC-MSC applications are also discussed.

Kindlin-2 promoted the progression of keloids through the Smad pathway and Fas/FasL pathway

Keloids are benign skin tumors characterized by aggressive growth. To date, there is no exact treatment because little is known about its pathological mechanism. Therefore, it is important to investigate the mechanism of its occurrence and development to identify therapeutic targets. In this study, the expression of Kindlin-2 was higher in keloid fibroblasts (KFs) than in normal skin fibroblasts (NFs). In vitro experiments showed that knocking down Kindlin-2 in KFs could promote cell apoptosis and inhibit cell proliferation, cell migration and invasion, and contractile capability. Western blot results showed that the phosphorylation of Smad3 in KFs was inhibited after knocking down Kindlin-2, inhibiting the activation of the Smad pathway. Moreover, knocking down Kindlin-2 increased the expression of Fas and FasL in KFs, which demonstrated that knocking down Kindlin-2 promoted the activation of the exogenous apoptotic pathway of KFs and then facilitated apoptosis. The above results revealed that knocking down Kindlin-2 in KFs can inhibit the activation of the Smad pathway and promote the activation of the Fas/FasL exogenous apoptosis pathway, thereby altering the cytological function of KFs. Therefore, Kindlin-2 might play an important role in the occurrence and development of keloids and could become a new target to treat keloids.

Kindlin-2 regulates the differentiation of 3T3-L1 preadipocytes: implications for wound healing

Background

Adipose tissue has been proven to play a crucial role in wound healing, while kindlin-2, an integrin-associated protein, has been shown to regulate cell adhesion, migration, and differentiation. This study aimed to explore its involvement in the cell differentiation of 3T3-L1 preadipocytes and its role in wound healing.

Methods

Cell adhesion, Cell Counting Kit-8 (CCK-8), Transwell, and in vitro wound healing assays, along with adipogenic and osteogenic differentiation induction were performed in 3T3-L1 preadipocytes in which kindlin-2 was knocked down or overexpressed. In vivo, kindlin-2 (+/−) transgenic mice were constructed, and wound healing was analyzed by immunohistochemistry (IHC) in a mouse dorsal wound model. Real-time polymerase chain reaction (RT-PCR) and western blotting were performed to analyze the expression of adipokines and adipogenic markers in mouse wound tissues. Adipogenic differentiation induction of adipose tissue stromal vascular fraction (SVF) were performed, and the expression of adipogenic markers in SVF was detected by western blotting. The target signaling pathway highly related to adipogenic differentiation was explored by computational biology and verified by western blotting.

Results

Knockdown of kindlin-2 was found to inhibit the adhesion, migration, and adipogenic differentiation of 3T3-L1 preadipocytes while promoting their osteogenic differentiation. In contrast, kindlin-2 overexpression resulted in increased adhesion, migration, and adipogenic differentiation of 3T3-L1 preadipocytes while reducing osteogenic differentiation. In vivo, downregulation of kindlin-2 inhibited adipogenesis in kindlin-2 transgenic mice, resulting in delayed wound healing by inhibiting inflammation, angiogenesis, collagen remodeling, and wound contraction. Mechanistically, we found that kindlin-2 could regulate adipogenic differentiation through PI3K/AKT/mTOR signaling pathway.

Conclusions

Our study revealed the essential role that kindlin-2 has in the differentiation and wound healing of 3T3-L1 preadipocytes, which offers a theoretical basis for further research and a novel strategy for wound healing.

Role of Kindlin-2 in cancer progression and metastasis

Cancer metastasis is a complex and multistep process whereby cancer cells escape the confines of the primary site to establish a new residency at distant sites. This multistep process is also known as the invasion-metastasis cascade. The biological and molecular mechanisms that control the invasion-metastasis cascade, which ultimately leads to the spread of cancer cells into distant sites, remain poorly understood. Kindlin-2 (K2) belongs to the 4.1-ezrin-ridixin-moesin (FERM) domain family of proteins, which interact with the cytoplasmic tails of β-integrin subunits, leading to the activation of extensive biological functions. These biological functions include cell migration, differentiation, cancer initiation, development, and invasion. In this review, we will discuss the various molecular signaling pathways that are regulated by K2 during the invasion-metastasis cascade of cancer tumors. These signaling pathways include TGFβ, Wnt/β-Catenin, Hedgehog, p53 and senescence, and cancer stem cell (CSC) maintenance. We will also discuss the molecular signaling pathways that regulate K2 function both at the transcriptional and the posttranslational levels. Finally, we will consider molecular mechanisms to specifically target K2 as novel therapeutic options for cancer treatment.

Kindlin-2 regulates hepatic stellate cells activation and liver fibrogenesis

Liver fibrosis, the common response associated with chronic liver diseases, ultimately leads to cirrhosis, a major public health problem worldwide. Activation of hepatic stellate cells (HSCs) by transforming growth factor (TGF)-β1 is a key step in liver fibrosis. Here we report that Kindlin-2 expression is elevated in the livers of mice with experimental liver fibrosis and also in the livers of patients with liver fibrosis. TGF-β1 increases Kindlin-2 expression in cultured HSCs in a p38 and ERK mitogen-activated protein kinase (MAPK)-dependent manner, partly. More importantly, Kindlin-2 deficiency significantly attenuated mouse liver fibrosis and HSC activation. Mechanistically, Kindlin-2 promotes TGF-β signaling through upregulation of Smad2 and Smad3 phosphorylation. Our work demonstrates an important role for Kindlin-2 in liver fibrosis, and inhibiting Kindlin-2 in the livers may represent a novel strategy to treat liver fibrosis.

Kindlins: Roles in development and cancer progression

The Kindlins are FERM domain proteins comprising three members (Kindlin-1, -2 and -3) which are evolutionarily conserved. Kindlins bind with β-integrin cytoplasmic tails and execute broad biological functions including directed cell migration, proliferation, differentiation and survival. In light of more and more evidence point to the importance of Kindlin family members in normal development and human diseases especially in cancers, we aim to portrait the profile of Kindlins in the regulation of embryonic development and cancer progression. We first summarize all the known binding proteins for individual member of Kindlin family. We then outline the Kindlin-regulated signaling pathways including Wnt/β-catenin, TGFβ, EGFR, and Hedgehog signalings. Furthermore, we descript the pivotal role of Kindlins in embryonic development in detail with notions that Kindlin-1 is highly expressed in endo/ectodermal originated tissues, Kindlin-2 is highly expressed in mesoderm-derived tissues and Kindlin-3 is highly expressed in mesoderm- and ectoderm-derived tissues. Deregulation of Kindlins is generally reported in cancers from different organs. We also briefly descript the role of Kindlins in other diseases. Finally, we update the recent understanding of how Kindlins are regulated and modified as well as the degradation mechanism of Kindlins, respectively.