Migration Of Mesenchymal Cells Research Articles

Extracellular ATP and adenosine in tumor microenvironment: Roles in epithelial-mesenchymal transition, cell migration, and invasion.

Under nonpathological conditions, the extracellular nucleotide concentration remains constant and low (nM range) because of a close balance between ATP release and ATP consumption. This balance is completely altered in cancer disease. Adenine and uridine nucleotides are found in the extracellular space of tumors in high millimolar (mM) concentrations acting as extracellular signaling molecules. In general, although uridine nucleotides may be involved in different tumor cell responses, purinergic signaling in cancer is preferentially focused on adenine nucleotides and nucleosides. Extracellular ATP can bind to specific receptors (P receptors) triggering different responses, or it can be hydrolyzed by ectoenzymes bound to cell membranes to render the final product adenosine. The latter pathway plays an important role in the increase of adenosine in tumor microenvironment. In this study, we will focus on extracellular ATP and adenosine, their effects acting as ligands of specific receptors, activating ectoenzymes, and promoting epithelial-mesenchymal transition, migration, and invasion in cancer cells. Finding the roles that these nucleotides play in tumor microenvironment may be important to design new intervention strategies in cancer therapies.

TNF-\u03b1-mediated m6A modification of ELMO1 triggers directional migration of mesenchymal stem cell in ankylosing spondylitis

Ankylosing spondylitis (AS) is a type of rheumatic disease characterized by chronic inflammation and pathological osteogenesis in the entheses. Previously, we demonstrated that enhanced osteogenic differentiation of MSC from AS patients (AS-MSC) resulted in pathological osteogenesis, and that during the enhanced osteogenic differentiation course, AS-MSC induced TNF-α-mediated local inflammation. However, whether TNF-α in turn affects AS-MSC remains unknown. Herein, we further demonstrate that a high-concentration TNF-α treatment triggers enhanced directional migration of AS-MSC in vitro and in vivo, which enforces AS pathogenesis. Mechanistically, TNF-α leads to increased expression of ELMO1 in AS-MSC, which is mediated by a METTL14 dependent m6A modification in ELMO1 3′UTR. Higher ELMO1 expression of AS-MSC is found in vivo in AS patients, and inhibiting ELMO1 in SKG mice produces therapeutic effects in this spondyloarthritis model. This study may provide insight into not only the pathogenesis but also clinical therapy for AS.

Enhanced spreading, migration and osteodifferentiation of HBMSCs on macroporous CS-Ta – A biocompatible macroporous coating for hard tissue repair

Macroporous tantalum (Ta) coating was produced on titanium alloy implant for bone repair by cold spray (CS) technology, which is a promising technology for oxygen sensitive materials. The surface characteristics as well as in vitro cytocompatibility were systematically evaluated. The results showed that a rough and macroporous CS-Ta coating was formed on the Ti6Al4V (TC4) alloy surfaces. The surface roughness showed a significant enhancement from 17.06 μm (CS-Ta-S), 27.48 μm (CS-Ta-M) to 39.21 μm (CS-Ta-L) with the increase of the average pore diameter of CS-Ta coatings from 138.25 μm, 198.25 μm to 355.56 μm. In vitro results showed that macroporous CS-Ta structure with tantalum pentoxide (Ta2O5) was more favorable to induce human bone marrow derived mesenchymal stem cells (HBMSCs) spreading, migration and osteodifferentiation than TC4. Compared with the micro-scaled structure outside the macropores, the surface micro-nano structure inside the macropores was more favorable to promote osteodifferentiation with enhanced alkaline phosphatase (ALP) activity and extracellular matrix (ECM) mineralization. In particular, CS-Ta-L with the largest pore size showed significantly enhanced integrin-α5 expression, cell migration, ALP activity, ECM mineralization as well as osteogenic-related genes including ALP, osteopontin (OPN) and osteocalcin (OCN) expression. Our results indicated that macroporous Ta coatings by CS, especially CS-Ta-L, may be promising for hard tissue repairs.

“Viscotaxis”- directed migration of mesenchymal stem cells in response to loss modulus gradient

Directed cell migration plays a crucial role in physiological and pathological conditions. One important mechanical cue, known to influence cell migration, is the gradient of substrate elastic modulus (E). However, the cellular microenvironment is viscoelastic and hence the elastic property alone is not sufficient to define its material characteristics. To bridge this gap, in this study, we investigated the influence of the gradient of viscous property of the substrate, as defined by loss modulus (G″) on cell migration. We cultured human mesenchymal stem cells (hMSCs) on a collagen-coated polyacrylamide gel with constant storage modulus (G′) but with a gradient in the loss modulus (G″). We found hMSCs to migrate from high to low loss modulus. We have termed this form of directional cellular migration as “Viscotaxis”. We hypothesize that the high loss modulus regime deforms more due to creep in the long timescale when subjected to cellular traction. Such differential deformation drives the observed Viscotaxis. To verify our hypothesis, we disrupted the actomyosin contractility with myosin inhibitor blebbistatin and ROCK inhibitor Y27632, and found the directional migration to disappear. Further, such time-dependent creep of the high loss material should lead to lower traction, shorter lifetime of the focal adhesions, and dynamic cell morphology, which was indeed found to be the case. Together, findings in this paper highlight the importance of considering the viscous modulus while preparing stiffness-based substrates for the field of tissue engineering. Statement of significanceWhile the effect of substrate elastic modulus has been investigated extensively in the context of cell biology, the role of substrate viscoelasticity is poorly understood. This omission is surprising as our body is not elastic, but viscoelastic. Hence, the role of viscoelasticity needs to be investigated at depth in various cellular contexts. One such important context is cell migration. Cell migration is important in morphogenesis, immune response, wound healing, and cancer, to name a few. While it is known that cells migrate when presented with a substrate with a rigidity gradient, cellular behavior in response to viscoelastic gradient has never been investigated. The findings of this paper not only reveal a completely novel cellular taxis or directed migration, it also improves our understanding of cell mechanics significantly.

Caveolin-1, a Key Mediator Across Multiple Pathways in Glioblastoma and an Independent Negative Biomarker of Patient Survival.

Glioblastoma (GB) remains an aggressive malignancy with an extremely poor prognosis. Discovering new candidate drug targets for GB remains an unmet medical need. Caveolin-1 (Cav-1) has been shown to act variously as both a tumour suppressor and tumour promoter in many cancers. The implications of Cav-1 expression in GB remains poorly understood. Using clinical and genomic databases we examined the relationship between tumour Cav-1 gene expression (including its spatial distribution) and clinical pathological parameters of the GB tumour and survival probability in a TCGA cohort (n=155) and CGGA cohort (n=220) of GB patients. High expression of Cav-1 represented a significant independent predictor of shortened survival (HR = 2.985, 5.1 vs 14.9 months) with a greater statistically significant impact in female patients and in the Proneural and Mesenchymal GB subtypes. High Cav-1 expression correlated with other factors associated with poor prognosis: IDH w/t status, high histological tumour grade and low KPS score. A total of 4879 differentially expressed genes (DEGs) in the GB tumour were found to correlate with Cav-1 expression (either positively or negatively). Pathway enrichment analysis highlighted an over-representation of these DEGs to certain biological pathways. Focusing on those that lie within a framework of epithelial to mesenchymal transition and tumour cell migration and invasion we identified 27 of these DEGs. We then examined the prognostic value of Cav-1 when used in combination with any of these 27 genes and identified a subset of combinations (with Cav-1) indicative of co-operative synergistic mechanisms of action. Overall, the work has confirmed Cav-1 can serve as an independent prognostic marker in GB, but also augment prognosis when used in combination with a panel of biomarkers or clinicopathologic parameters. Moreover, Cav-1 appears to be linked to many signalling entities within the GB tumour and as such this work begins to substantiate Cav-1 or its associated signalling partners as candidate target for GB new drug discovery.

Polyherbal formulation Anoac‑H suppresses theexpression of RANTES and VEGF for themanagement of bleeding hemorrhoids and fistula.

Hemorrhoids and fistula are considered the most common anorectal conditions in the general population. These conditions affect the quality of a patient's life by causing pain and bleeding during defecation or even in the resting state. Lower grades of hemorrhoids may be controlled by traditional measures. However, surgery is an effective treatment option in recurrent-lower and higher-grade hemorrhoids. Surgical procedures are associated with various complications, including pain and delayed wound healing. Recurrence of hemorrhoids is also a major concern in the post-operative period. An anal fistula is the connection between the anus and the skin and causes severe pain, swelling, as well as blood and pus discharge. Fistula has serious social and economic consequences. Hence, it is important to understand the pathophysiology and molecular pathology of hemorrhoids and fistula, to identify the molecular targets and to develop pharmacological-interventions. In a previous study by our group, the polyherbal formulation Anoac-H was developed for the treatment of different stages of hemorrhoids and fistula, and it was demonstrated that Anoac-H is an effective formulation for treating hemorrhoids. However, the molecular mode of action of Anoac-H on hemorrhoids and fistula had remained elusive. In the present study, it was determined that this formulation reduces the migration of mesenchymal (fibroblasts) and immune (RAW 264.7) cells without affecting their viability. It was also observed that Anoac-H suppresses the expression of regulated upon activation, normal T cell expressed and presumably secreted (RANTES) and VEGF in fibroblasts and macrophages. Inflammation and elevated expression of RANTES and VEGF were observed in hemorrhoids and fistula. However, inflammation, as well as the expression of RANTES and VEGF, were significantly reduced in treated human hemorrhoid and fistula tissues as compared to untreated ones, confirming the in vitro results.

SDF-1α/OPF/BP Composites Enhance the Migrating and Osteogenic Abilities of Mesenchymal Stem Cells.

In situ cell recruitment is a promising regenerative medicine strategy with the purpose of tissue regeneration without stem cell transplantation. This chemotaxis-based strategy is aimed at ensuring a restorative environment through the release of chemokines that promote site-specific migration of healing cell populations. Stromal cell-derived factor-1α (SDF-1α) is a critical chemokine that can regulate the migration of mesenchymal stem cells (MSCs). Accordingly, here, SDF-1α-loaded microporous oligo[poly(ethylene glycol) fumarate]/bis[2-(methacryloyloxy)ethyl] phosphate composites (SDF-1α/OPF/BP) were engineered and probed. SDF-1α/OPF/BP composites were loaded with escalating SDF-1α concentrations, namely, 0 ng/ml, 50 ng/ml, 100 ng/ml, and 200 ng/ml, and were cocultured with MSC. Scratching assay, Transwell assay, and three-dimensional migration model were utilized to assess the migration response of MSCs. Immunofluorescence staining of Runx2 and osteopontin (OPN), ELISA assay of osteocalcin (OCN) and alkaline phosphatase (ALP), and Alizarin Red S staining were conducted to assess the osteogenesis of MSCs. All SDF-1α/OPF/BP composites engendered a release of SDF-1α (>80%) during the first four days. SDF-1α released from the composites significantly promoted migration and osteogenic differentiation of MSCs documented by upregulated expression of osteogenic-related proteins, ALP, Runx2, OCN, and OPN. SDF-1α at 100 ng/ml was optimal for enhanced migration and osteogenic proficiency. Thus, designed SDF-1α/OPF/BP composites were competent in promoting the homing and osteogenesis of MSCs and thus offer a promising bioactive scaffold candidate for on-demand bone tissue regeneration.

Fibronectin within Sodium Alginate Microcapsules Improved Osteogenic Differentiation of BMMSCs in Dose Dependent Manner by Targeting SP7, OCN, CDK1, ZBTB16, and Twist1 Expression.

Purpose: Insoluble fibronectin as an extracellular matrix (ECM) protein has the potential to promote proliferation, differentiation, and migration of mesenchymal stem cells (MSCs). However, there is limited information about the effects of fibronectin various concentrations on bone marrow-derived MSCs (BMMSCs) function and differentiation. Methods: In this experimental study, using a gel injection device, BMMSCs were encapsulated in sodium alginate microcapsules containing 1.25% alginate, 1% gelatin, and fibronectin (0.01, 0.05, 0.1, and 0.2 μg/ml). MTT assay was used to examine the proliferation of BMMSCs. Also, BMMSCs apoptosis were analyzed using Annexin-V/PI staining and fluorescence activated cell sorting (FACS). Alkaline phosphatase (ALP) test was conducted to assess BMMSCs osteogenic differentiation potential. Finally, mRNA expression levels of the SP7, osteocalcin (OCN), Twist Family BHLH Transcription Factor 1 (Twist1), Peroxisome proliferator‐activated receptor γ2 (PPARγ2), Cyclin-dependent kinase 1 (CDK1), and Zinc Finger and BTB Domain Containing 16 (ZBTB16), following exposure with fibronectin 0.1 μg/ml. Results: According to results, fibronectin had the potential to promote proliferation rates of the BMMSCs, in particular at 0.1 and 0.2 μg/ml concentrations. we showed that the fibronectin was not able to modify apoptosis rates of the BMMSCs. ALP test results approved the notable potential of the fibronectin, to trigger osteogenic differentiation of the BMMSCs. Also, RT-PCR results indicated that fibronectin 0.1 μg/ml could augment osteogenic differentiation of cultured BMMSCs through targeting of OCN, SP7, Twist1, CDK1, and ZBTB16, strongly or slightly. Conclusion: Results showed that fibronectin can improve proliferation and osteogenic differentiation of BMMSCs without any effect on these cells' survival.

Three-dimensional migration of human amniotic fluid stem cells involves mesenchymal and amoeboid modes and is regulated by mTORC1.

Three‐dimensional (3D) cell migration is an integral part of many physiologic processes. Although being well studied in the context of adult tissue homeostasis and cancer development, remarkably little is known about the invasive behavior of human stem cells. Using two different kinds of invasion assays, this study aimed at investigating and characterizing the 3D migratory capacity of human amniotic fluid stem cells (hAFSCs), a well‐established fetal stem cell type. Eight hAFSC lines were found to harbor pronounced potential to penetrate basement membrane (BM)‐like matrices. Morphological examination and inhibitor approaches revealed that 3D migration of hAFSCs involves both the matrix metalloprotease‐dependent mesenchymal, elongated mode and the Rho‐associated protein kinase‐dependent amoeboid, round mode. Moreover, hAFSCs could be shown to harbor transendothelial migration capacity and to exhibit a motility‐associated marker expression pattern. Finally, the potential to cross extracellular matrix was found to be induced by mTORC1‐activating growth factors and reduced by blocking mTORC1 activity. Taken together, this report provides the first demonstration that human stem cells exhibit mTORC1‐dependent invasive capacity and can concurrently make use of mesenchymal and amoeboid 3D cell migration modes, which represents an important step toward the full biological characterization of fetal human stem cells with relevance to both developmental research and stem cell‐based therapy.

Atorvastatin Pretreatment Ameliorates Mesenchymal Stem Cell Migration through miR-146a/CXCR4 Signaling.

We previously found that atorvastatin (ATV) enhanced mesenchymal stem cells (MSCs) migration, by a yet unknown mechanism. CXC chemokine receptor 4 (CXCR4) is critical to cell migration and regulated by microRNA-146a (miR-146a). Therefore, this study aimed to assess whether ATV ameliorates MSCs migration through miR-146a/CXCR4 signaling. Expression of CXCR4 was evaluated by flow cytometry. Expression of miR-146a was examined by reverse transcription-quantitative polymerase chain reaction. A transwell system was used to assess the migration ability of MSCs. Recruitment of systematically delivered MSCs to the infarcted heart was evaluated in Sprague-Dawley rats with acute myocardial infarction (AMI). Mimics of miR-146a were used in vitro, and miR-146a overexpression lentivirus was used in vivo, to assess the role of miR-146a in the migration ability of MSCs. The results showed that ATV pretreatment in vitro upregulated CXCR4 and induced MSCs migration. In addition, flow cytometry demonstrated that miR-146a mimics suppressed CXCR4, and ATV pretreatment no longer ameliorated MSCs migration because of decreased CXCR4. In the AMI model, miR-146a-overexpressing MSCs increased infarct size and fibrosis. The miR-146a/CXCR4 signaling pathway contributes to MSCs migration and homing induced by ATV pretreatment. miR-146a may be a novel therapeutic target for stimulating MSCs migration to the ischemic tissue for improved repair.

Bioactive Glass Fiber-Reinforced Plastic Composites Prompt a Crystallographic Lophelia Atoll-Like Skeletal Microarchitecture Actuating Periosteal Cambium.

The touchstone for bone replacing or anchoring trauma implants, besides resorption, includes functional ankylosis at a fixation point and replacement by viable functional neo-bone tissues. These parameters redefined the concept of "resorbability" as "bioresorbability." Interference screws are the most commonly used resorbable anchoring implants for anterior cruciate ligament (ACL) reconstruction (surgery). Over the years, the bioresorbable screw fixation armamentarium has amplified countless choices, but instability and postimplantation complications have raised concerns about its reliability and efficacy. Owing to this interest, in this work, bioactive glass fiber-reinforced plastic (BGFP) composites with (BGFPnb5) and without (BGFP5) niobicoxide composing multiplexed network modifiers are reported as bioresorbable bone-anchoring substitutes. These synergistically designed composites have a fabricated structure of continuous, unidirectional BG fibers reinforced in an epoxy resin matrix using "melt-drawing and microfabrication" technology. The BGFP microarchitecture is comprised of multiplexed oxide components that influence bioactive response in a distinctive lophelia atoll-like apatite formation. Furthermore, it assists in the proliferation, adherence, and migration of bone marrow-derived mesenchymal stem cells. It also exhibits superior physicochemical characteristics such as surface roughness, hydrophilic exposure, distinctive flexural strength, and bioresorption. Thus, it induces restorative bone osseointegration and osteoconduction and actuates periosteum function. In addition, the BGFP influences the reduction of DH5-α Escherichia coli in suspension culture, demonstrating potential antibacterial efficacy. In conclusion, the BGFP composite therapeutic efficacy demonstrates distinctive material characteristics aiding in bone regeneration and restoration that could serve as a pioneer in orthopedic regenerative medicine.

Abstract 2882: Coronin 1B overexpression promotes invasion of HPV- HNSCC

Abstract Introduction: Amplification of chromosome 11q13 is the most common DNA aberration in human papilloma virus negative (HPV-) head and neck squamous cell carcinoma. (HSNCC). The 11q13 region encodes various genes known to enhance invasion and drive tumor progression. CORO1B (coronin 1B) flanks the core 11q13 region and is amplified in 7-14% of HNSCC cases. Coronin 1B governs cell motility in fibroblasts by negatively regulating the ability of the Arp 2/3 nucleator cortactin to stabilize the actin cytoskeleton during mesenchymal cell migration. This study seeks to determine the impact of CORO1B amplification and protein overexpression in driving HNSCC progression. Experimental Procedures: Two patient cohorts were used to assess the impact of CORO1B amplification or overexpression on patient outcome. In addition, HNSCC cell lines lacking or overexpressing coronin 1B were assayed for invadopodia function using gelatin degradation assays. Three-dimensional invasion was analyzed using tumor spheroid and organotypic assays. Invasive and cervical lymph node metastatic potential of CORO1B was evaluated using knockdown and overexpression cells in orthotopic tongue models. Data Summary: CORO1B amplification and overexpression in patient tumors correlates with enhanced patient decline. Coronin 1B-null cell lines display decreased invadopodia function, with a 30-60% decrease in extracellular matrix-mimicking gelatin degradation. HNSCC tumor spheroids lacking coronin 1B expression decreased 3D invasion in native collagen I, while overexpression enhanced invasive capabilities in both tumor spheroids and organotypic cultures. Coronin 1B knockdown cells show decreased lymph node metastasis, while mice with tumors overexpression coronin 1B have enhanced lymph node metastasis and decreased survival. CORO1B amplification protein overexpression predict poor overall patient survival. Conclusion: The identification of coronin 1B overexpression as an important mediator in promoting HNSCC invasive processes may define a novel aggressive subset of locoregional involved HNSCC, warranting enhanced clinical intervention. Citation Format: Jessica L. Allen, Elyse L. Walk, Kristen L. Rhodes, Steven M. Markwell, Brenen W. Papenberg, Hong Wu, Marileila Garcia, James E. Bear, Scott A. Weed. Coronin 1B overexpression promotes invasion of HPV- HNSCC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2882.

Abstract 1940: Autophagy mediates leptin induced migration and erk activation in breast cancer cells

Abstract Autophagy is an intracellular recycling process active in eukaryotic cells which involves the formation of an autophagosome that delivers cytoplasmic components to the lysosome for degradation. This process occurs at low rates under basal conditions, but it can be induced by diverse stress conditions such as starvation, hypoxia or metabolic disorders. Autophagic flux can also be enhanced in response to hormones, including leptin. Leptin is considered a pro-tumorigenic protein whose circulating levels have been related to a bad prognosis in obese breast cancer patients. It has been recently demonstrated that leptin can induce autophagy in cancer cell lines from different tissues, suggesting that autophagy could modulate the pro-tumorigenic effects associated with leptin. In this study, the role of autophagy in leptin-induced proliferation, migration, apoptosis and ERK phosphorylation in breast cancer cell lines was evaluated. Methods: MCF7 estrogen receptor positive and MDA-MB-231 triple negative breast cancer cell lines were used. MCF7 and MDA-MB-231 cell lines were stimulated with 400 and 50 ng/ml of leptin, respectively. Autophagy was assessed by LC3-II and p62 protein levels by western blot, and autophagosome formation by fluorescence microscopy. Proliferation and migration were assessed by real-time microscopy in an IncuCyte analyzer; and cell death was evaluated by fluorescence analysis of caspase activity. Changes in ERK phosphorylation were measure by western blot. Results: Leptin increased autophagy in MCF7 cells but not in triple negative MDA-MB-231 cells. In MCF7 cells, autophagy inhibition reduced leptin-induced cell proliferation, changes associated to a mesenchymal morphology, cell migration, and ERK activation. In MDA-MB-231 cells, autophagy inhibition reduced proliferation and increased apoptosis independently of leptin treatment. In both cell lines, leptin-induced migration and ERK phosphorylation were reduced by the inhibition of autophagy. Conclusion: Autophagy was important for increased cancer cell migration induced by leptin and for the maintenance of ERK phosphorylation. Our data suggest a potential use for the inhibition of autophagy in breast cancer associated with obesity. Citation Format: Alin García Miranda, Karen A. Solano Alcalá, José B. Montes Alvarado, Julio Reyes Leyva, Paola Maycotte, Eduardo Castañeda Saucedo. Autophagy mediates leptin induced migration and erk activation in breast cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1940.

Polydopamine-based biofunctional substrate coating promotes mesenchymal stem cell migration

Rapid migration of mesenchymal stem cells (MSCs) on device surfaces could support in vivo tissue integration and might facilitate in vitro organoid formation. Here, polydopamine (PDA) is explored as a biofunctional coating to effectively promote MSC motility. It is hypothesized that PDA stimulates fibronectin deposition and in this way enhances integrin-mediated migration capability. The random and directional cell migration was investigated by time-lapse microscopy and gap closure assay respectively, and analysed with softwares as computational tools. A higher amount of deposited fibronectin was observed on PDA substrate, compared to the non-coated substrate. The integrin β1 activation and focal adhesion kinase (FAK) phosphorylation at Y397 were enhanced on PDA substrate, but the F-actin cytoskeleton was not altered, suggesting MSC migration on PDA was regulated by integrin initiated FAK signalling. This study strengthens the biofunctionality of PDA coating for regulating stem cells and offering a way of facilitating tissue integration of devices.Graphic abstractPolydopamine-coated substrate induces increased fibronectin deposition of mesenchymal stem cells, and promotes cell migration via integrin-initiated FAK signaling, compared to non-coated polystyrene-based standard tissue culture surface. In this way, multifunctional PDA coating could support in vivo tissue integration on implant surface and promote in vitro organoid formation.

SP1-Mediated Upregulation of Long Noncoding RNA ZFAS1 Involved in Non-syndromic Cleft Lip and Palate via Inactivating WNT/β-Catenin Signaling Pathway.

Non-syndromic cleft lip and palate (NSCLP) is one of the most common congenital malformations with multifactorial etiology. Although long non-coding RNAs (lncRNAs) have been implicated in the development of lip and palate, their roles in NSCLP are not fully elucidated. This study aimed to investigate how dysregulated lncRNAs contribute to NSCLP. Using lncRNA sequencing, bioinformatics analysis, and clinical tissue sample detection, we identified that lncRNA ZFAS1 was significantly upregulated in NSCLP. The upregulation of ZFAS1 mediated by SP1 transcription factor (SP1) inhibited expression levels of Wnt family member 4 (WNT4) through the binding with CCCTC-binding factor (CTCF), subsequently inactivating the WNT/β-catenin signaling pathway, which has been reported to play a significant role on the development of lip and palate. Moreover, in vitro, the overexpression of ZFAS1 inhibited cell proliferation and migration in human oral keratinocytes and human umbilical cord mesenchymal stem cells (HUC-MSCs) and also repressed chondrogenic differentiation of HUC-MSCs. In vivo, ZFAS1 suppressed cell proliferation and numbers of chondrocyte in the zebrafish ethmoid plate. In summary, these results indicated that ZFAS1 may be involved in NSCLP by affecting cell proliferation, migration, and chondrogenic differentiation through inactivating the WNT/β-catenin signaling pathway.

Biological, chemical and mechanical factors regulating migration and homing of mesenchymal stem cells.

Mesenchymal stem cells (MSCs) are a population of primary and non-specialized cells, which can be isolated from various tissues. Currently, MSCs are key players in cellular therapy and regenerative medicine. However, the possibility of using MSCs in the treatment of many diseases needs to be preceded, though, by in-depth analysis of their properties, especially by determining the mechanism of tissue homing as well as the mechanism, due to which cells contribute to tissue regeneration. This review is intended to present information on recent findings regarding the mechanism of recruitment and tissue homing by MSCs and discuss current hypotheses for how MSCs can reach target tissues.

Different translation dynamics of β- and γ-actin regulates cell migration.

β- and γ-cytoplasmic actins are ubiquitously expressed in every cell type and are nearly identical at the amino acid level but play vastly different roles in vivo. Their essential roles in embryogenesis and mesenchymal cell migration critically depend on the nucleotide sequences of their genes, rather than their amino acid sequences; however, it is unclear which gene elements underlie this effect. Here we address the specific role of the coding sequence in β- and γ-cytoplasmic actins' intracellular functions, using stable polyclonal populations of immortalized mouse embryonic fibroblasts with exogenously expressed actin isoforms and their 'codon-switched' variants. When targeted to the cell periphery using β-actin 3'UTR; β-actin and γ-actin have differential effects on cell migration. These effects directly depend on the coding sequence. Single-molecule measurements of actin isoform translation, combined with fluorescence recovery after photobleaching, demonstrate a pronounced difference in β- and γ-actins' translation elongation rates in cells, leading to changes in their dynamics at focal adhesions, impairments in actin bundle formation, and reduced cell anchoring to the substrate during migration. Our results demonstrate that coding sequence-mediated differences in actin translation play a key role in cell migration.

Bone morphogenetic protein 2-induced cellular chemotaxis drives tissue patterning during critical-sized bone defect healing: an in silico study

Critical-sized bone defects are critical healing conditions that, if left untreated, often lead to non-unions. To reduce the risk, critical-sized bone defects are often treated with recombinant human BMP-2. Although enhanced bone tissue formation is observed when BMP-2 is administered locally to the defect, spatial and temporal distribution of callus tissue often differs from that found during regular bone healing or in defects treated differently. How this altered tissue patterning due to BMP-2 treatment is linked to mechano-biological principles at the cellular scale remains largely unknown. In this study, the mechano-biological regulation of BMP-2-treated critical-sized bone defect healing was investigated using a multiphysics multiscale in silico approach. Finite element and agent-based modeling techniques were combined to simulate healing within a critical-sized bone defect (5 mm) in a rat femur. Computer model predictions were compared to in vivo microCT data outcome of bone tissue patterning at 2, 4, and 6 weeks postoperation. In vivo, BMP-2 treatment led to complete healing through periosteal bone bridging already after 2 weeks postoperation. Computer model simulations showed that the BMP-2 specific tissue patterning can be explained by the migration of mesenchymal stromal cells to regions with a specific concentration of BMP-2 (chemotaxis). This study shows how computational modeling can help us to further understand the mechanisms behind treatment effects on compromised healing conditions as well as to optimize future treatment strategies.

Interleukin-1β-induced matrix metalloproteinase-3 via ERK1/2 pathway to promote mesenchymal stem cell migration.

Human umbilical cord Wharton’s jelly derived mesenchymal stem cells (hUCMSCs), a source of cell therapy, have received a great deal of attention due to their homing or migrating ability in response to signals emanating from damaged sites. It has been found that IL-1β possesses the ability to induce the expression of matrix metalloproteinase-3 (MMP-3) in bone marrow MSCs. MMP-3 is involved in cell migration in various types of cells, including glioblastoma, vascular smooth muscle, and adult neural progenitor cells. In this study, we proposed that IL-1β influences hUCMSCs migration involving MMP-3. The expression level of MMP-3 in IL-1β-induced hUCMSCs was verified using cDNA microarray analysis, quantitative real-time PCR, ELISA and Western blot. Wound-healing and trans-well assay were used to investigate the cell migration and invasion ability of IL-1β-treated hUCMSCs. In addition, we pre-treated hUCMSCs with interleukin-1 receptor antagonist, MMP-3 inhibitors (ALX-260-165, UK 356618), or transfected with MMP-3 siRNA to confirm the role of MMP3 in IL-1β-induced cell migration. Our results showed that IL-1β induced MMP-3 expression is related to the migration of hUCMSCs. Moreover, extracellular signal-regulated protein kinases 1 and 2 (ERK1/2) inhibitor U0126, p38 inhibitor SB205380, JNK inhibitor SP600125 and Akt inhibitor GSK 690693 decreased IL-1β-induced MMP-3 mRNA and protein expression. The migration and invasion ability analyses showed that these inhibitors attenuated the IL-1β-induced migration and invasion ability of hUCMSCs. In conclusion, we have found that IL-1β induces the expression of MMP-3 through ERK1/2, JNK, p38 MAPK and Akt signaling pathways to enhance the migration of hUCMSCs. These results provide further understanding of the mechanisms in IL-1β-induced hUCMSCs migration to injury sites.

Let-7f miRNA regulates SDF-1\u03b1- and hypoxia-promoted migration of mesenchymal stem cells and attenuates mammary tumor growth upon exosomal release

Bone marrow-derived human mesenchymal stem cells (hMSCs) are recruited to damaged or inflamed tissues where they contribute to tissue repair. This multi-step process involves chemokine-directed invasion of hMSCs and on-site release of factors that influence target cells or tumor tissues. However, the underlying molecular mechanisms are largely unclear. Previously, we described that microRNA let-7f controls hMSC differentiation. Here, we investigated the role of let-7f in chemotactic invasion and paracrine anti-tumor effects. Incubation with stromal cell-derived factor-1α (SDF-1α) or inflammatory cytokines upregulated let-7f expression in hMSCs. Transfection of hMSCs with let-7f mimics enhanced CXCR4-dependent invasion by augmentation of pericellular proteolysis and release of matrix metalloproteinase-9. Hypoxia-induced stabilization of the hypoxia-inducible factor 1 alpha in hMSCs promoted cell invasion via let-7f and activation of autophagy. Dependent on its endogenous level, let-7f facilitated hMSC motility and invasion through regulation of the autophagic flux in these cells. In addition, secreted let-7f encapsulated in exosomes was increased upon upregulation of endogenous let-7f by treatment of the cells with SDF-1α, hypoxia, or induction of autophagy. In recipient 4T1 tumor cells, hMSC-derived exosomal let-7f attenuated proliferation and invasion. Moreover, implantation of 3D spheroids composed of hMSCs and 4T1 cells into a breast cancer mouse model demonstrated that hMSCs overexpressing let-7f inhibited tumor growth in vivo. Our findings provide evidence that let-7f is pivotal in the regulation of hMSC invasion in response to inflammation and hypoxia, suggesting that exosomal let-7f exhibits paracrine anti-tumor effects.