Mesenchymal stem cell migration is regulated by fibronectin through α5β1-integrin-mediated activation of PDGFR-β and potentiation of growth factor signals

Evaluation of the effect of platelet-derived growth factor-BB on the biological activity of human mandibular bone marrow-derived mesenchymal stem cells

OBJECTIVE

This study aimed to investigate the effects of platelet-derived growth factor-BB (PDGF-BB) on the biological activities of human mandibular bone marrow-derived mesenchymal stem cells (MBMSCs).

DESIGN

PDGF-BB (20 ng/mL) was used to treat MBMSCs, and its effects on their proliferation, osteogenic differentiation, and migration were evaluated. Cell proliferation was evaluated using a WST-1 assay. Osteogenic differentiation was evaluated by measuring the mineralization potential and alkaline phosphatase activity. Cell migration was evaluated using wound healing and Transwell chamber assays. Cytoskeletal reorganization and adhesion dynamics were evaluated using immunofluorescence staining. Changes in intracellular signaling in MBMSCs induced by PDGF-BB stimulation were evaluated using western blotting. Furthermore, we investigated Girdin signaling as the molecular mechanisms underlying the regulation of PDGF-BB-induced cell migration.

RESULTS

PDGF-BB treatment did not affect the proliferation or osteogenic differentiation of MBMSCs. PDGF-BB promoted the migration of MBMSCs. PDGF-BB treatment enhanced F-actin filament formation and paxillin localization at the leading edge of cells. PDGF-BB treatment activated Akt signaling in MBMSCs, and the inhibition of Akt signaling effectively suppressed PDGF-BB-induced Akt activation and migration. PDGF-BB promoted the phosphorylation of Girdin in MBMSCs, and the inhibition of Akt signaling attenuated PDGF-BB-induced Girdin activation.

CONCLUSION

This study demonstrated that PDGF-BB strongly induces the migration of MBMSCs without affecting their proliferation or osteogenic differentiation. Furthermore, PDGF-BB-induced migration of MBMSCs may be mediated through the Akt/Girdin signaling pathway. These findings provide important insight into the molecular mechanisms underlying PDGF-BB-induced periodontal tissue regeneration.

A preclinical study on cell therapy as an adjunct to surgical decompression in degenerative cervical myelopathy via accelerating blood spinal cord barrier reconstitution and neurological recovery

BACKGROUND

Degenerative cervical myelopathy (DCM) is the most common disorder affecting the cervical spinal cord in the developed world. Whilst surgery is effective, many patients suffer from residual neurological deficits post-decompression. Cell-based therapies have been studied for traumatic spinal cord injury models but not DCM and may be efficacious as an adjunct to surgical decompression via trophic factor secretion, parenchymal engraftment and/or blood spinal cord barrier reconstitution.

METHODS

98 SD rats at age 10-12 weeks underwent five weeks of cervical compression by inserting a water-absorbent polyurethane polymer at the C4 epidural space or received sham surgery. Decompression surgery was performed by removing the polymer. Treatment groups received BM-MSCs (bone marrow-derived marrow stromal cells) or BM-neurospheres intravenously or intracisternally at the time of decompression. Locomotor function (BBB testing, rotarod testing, Forelimb Score, and Hind Limb Score) and blood -spinal cord barrier (BSCB) recovery via Evans blue extravasation was observed in 35 rats during the 10-week post-decompression recovery period. 30 rats were used to determine in vivo cell distribution and comparative efficacy of intravenous (IV) or intracisternal (CIS) injection. The remaining rats were sacrificed to assess for the engraftment of transplanted cells. In vivo bioluminescent imaging (BLI) of EGFP-Luciferase BM-MSCs localized cells grossly to organ systems, whilst immunohistochemistry (IHC) of spinal cord specimens targeting anti-human antigens facilitated localization at the site of compression.

RESULTS

BSCB disruption indicated by Evans Blue dye extravasation peaked at Week-4 post-decompression (DW4) and correlated with endoglin expression. Locomotor recovery after polymer removal was delayed with minor improvements observed by Week-8 post-decompression (DW8). IV and CIS injection of BM-MSCs did not lead to significant improvement in locomotor function (p = 0.101, Rotarod Test: PBS vs. CIS) nor of BSCB reconstitution by Day 10 post-decompression. BLI showed significant peripheral organ entrapment of IV BM-MSCs, while CIS BM-MSCs remained in the cervical region, with IHC demonstrating localization to the pia mater. At Day 20, both CIS BM-MSCs and BM-neurospheres similarly failed to significantly improve locomotor function (p = 0.136, Rotarod Test: PBS vs. BM-neurospheres) and transplanted cells were absent from the cervical cord parenchyma.

CONCLUSION

Human BM-MSCs and BM-neurospheres demonstrate limited efficacy as adjunct therapy to cervical decompression under the present experimental conditions. Adjusting insertable polymer hardness, cell number, and timing of cell transplantation may be future means to demonstrate potential therapeutic effectiveness.

The phosphorylation of Pak1 by Erk1/2 to drive cell migration requires Arl4D acting as a scaffolding protein

Activation of extracellular signal-regulated kinases 1 and 2 (Erk1/2; also known as MAPK3 and MAPK1, respectively) at the plasma membrane usually leads to their translocation to various intracellular sites, where scaffolding proteins mediate substrate targeting. However, in platelet-derived growth factor (PDGF)-induced signaling, Erk1/2 phosphorylate Pak1 to drive cell migration while remaining at the plasma membrane, raising the question of whether scaffolding proteins are required. Similarly, the small GTPase Arf-like protein 4D (Arl4D) promotes cell migration by recruiting Pak1 to the plasma membrane and facilitating its phosphorylation, although the mechanism linking recruitment to phosphorylation remains unclear. To address these questions, we show that Arl4D functions as a scaffolding protein by recruiting Erk1/2 and Pak1 to the plasma membrane, assembling them into a functional complex. This complex allows Erk1/2 to phosphorylate Pak1, supporting the role of the latter in cell migration. Our findings identify Arl4D as a novel regulator of Erk1/2, reveal a conserved role of scaffolding proteins in Erk1/2 substrate targeting, and uncover an unrecognized interplay among Arl4D, Erk1/2 and Pak1. These insights provide a deeper understanding of the molecular coordination underlying Pak1-mediated cell migration and its regulation by Erk1/2 and Arl4D.

The Cellular and Molecular Characteristics of Postnatal Human Thymus Stromal Stem Cells

Background: The thymus is the central hub of T-cell differentiation, where epithelial cells guide the process of their maturation. Objective: Our goal was to identify and describe progenitor cells within the human thymus that can differentiate into epithelial cells. Methods: When we plated enriched thymic cells in 3D culture conditions, rare individual cells capable of self-renewal and differentiation formed spheroids. Results: Both neonatal and adult thymuses produced similar numbers of spheroids, suggesting that progenitor potential remains consistent across age groups. Some cells within the spheres express genes typical of mature epithelial cells, while others express genes associated with the immature compartment active during thymic organogenesis. However, there were also cells expressing PDGFRβ. We treated the tissues with 2-deoxyguanosine before digestion, which improved the yield of progenitor cells. We also cultured the enriched stromal thymocytes with Cyr61 and Interleukin-22, which affected the spheroid size. Conclusions: Our efforts towards thymic reconstitution are ongoing, but our research uncovers previously unknown characteristics of the elusive epithelial progenitor population.

Efficacy and safety of mesenchymal stem cell therapy in acute on chronic liver failure: a systematic review and meta-analysis of randomized controlled clinical trials

BACKGROUND

Acute-on-chronic liver failure has become a serious global health burden, which is characterized by an acute deterioration of liver function, rapidly evolving organ failure, and high short-term mortality in patients with chronic liver disease. The pathogenesis includes extensive hepatic necrosis, which is related to intense systemic inflammation and subsequently causes the inflammatory cytokine storm, resulting in portal hypertension, organ dysfunction, and organ failure. Mesenchymal stem cells can function as seed cells to remodel and repair damaged liver tissues, thus showing potential therapeutic alternatives for patients with chronic liver disease. However, standard treatment protocols for mesenchymal stem cells in acute-on-chronic liver failure patients have not been established.

METHODS

We conducted a detailed search from PubMed/Medline, Web of Science, EMBASE, and Cochrane Library to find randomized controlled trials published before October 23, 2021. We formulated criteria for the literature screening according to the PICOS principle (Population, Intervention, Comparison, Outcome, Study design). Subsequently, the bias risk assessment tool was used to assess the quality of all enrolled studies. Finally, outcome measurements including the model of end-stage liver disease score, albumin, total bilirubin, coagulation function, and aminotransferase were extracted for statistical analysis.

RESULTS

A total of 7 clinical trials were included. The results of enrolled studies indicated that patients with acute-on-chronic liver failure who received mesenchymal stem cells inoculation showed a decreased MELD score in 4 weeks and 24 weeks, compared with counterparts who received conventional treatment. Reciprocally, mesenchymal stem cells inoculation improved the ALB levels in 4 weeks and 24 weeks. For secondary indicators, mesenchymal stem cells treatment significantly reduced INR levels and ALT levels, compared with the control group. Our results showed no significant differences in the incidence of adverse reactions or serious adverse events monitored in patients after mesenchymal stem cells inoculation.

CONCLUSION

This meta-analysis indicated that mesenchymal stem cell infusion is effective and safe in the treatment of patients with acute-on-chronic liver failure. Without increasing the incidence of adverse events or serious adverse events, MSC treatment improved liver function including a decrease in MELD score and an increase in ALB levels in patients with acute-on-chronic liver failure. However, large-cohort randomized controlled trials with longer follow-up periods are required to further confirm our conclusions.

Adipose-Derived Stromal Cells Exposed to RGD Motifs Enter an Angiogenic Stage Regulating Endothelial Cells

Adipose-derived stromal cells (ASCs) possess significant regenerative potential, playing a key role in tissue repair and angiogenesis. During wound healing, ASC interacts with the extracellular matrix by recognizing arginylglycylaspartic acid (RGD) motifs, which are crucial for mediating these functions. This study investigates how RGD exposure influences ASC behavior, with a focus on angiogenesis. To mimic the wound-healing environment, ASC were cultured in a porcine gelatin sponge, an RGD-exposing matrix. Transcriptomics revealed that ASC cultured in gelatin exhibited an upregulated expression of genes associated with inflammation, angiogenesis, and tissue repair compared to ASC in suspension. Pro-inflammatory and pro-angiogenic factors, including IL-1, IL-6, IL-8, and VEGF, were significantly elevated. Functional assays further demonstrated that ASC-conditioned media enhanced endothelial cell migration, tubulogenesis, and reduced endothelial permeability, all critical processes in angiogenesis. Notably, ASC-conditioned media also promoted vasculogenesis in human vascular organoids. The inhibition of ASC-RGD interactions using the cyclic peptide cilengitide reversed these effects, underscoring the essential role of RGD-integrin interactions in ASC-mediated angiogenesis. These findings suggest that gelatin sponges enhance ASC's regenerative and angiogenic properties via RGD-dependent mechanisms, offering promising therapeutic potential for tissue repair and vascular regeneration. Understanding how RGD modulates ASC behavior provides valuable insights into advancing cell-based regenerative therapies.

Development of bioengineered 3D patient derived breast cancer organoid model focusing dynamic fibroblast-stem cell reciprocity

Three-dimensional (3D) models, such as tumor spheroids and organoids, are increasingly developed by integrating tissue engineering, regenerative medicine, and personalized therapy strategies. These advanced 3Din-vitromodels are not merely endpoint-driven but also offer the flexibility to be customized or modulated according to specific disease parameters. Unlike traditional 2D monolayer cultures, which inadequately capture the complexities of solid tumors, 3D co-culture systems provide a more accurate representation of the tumor microenvironment. This includes critical interactions with mesenchymal stem/stromal cells (MSCs) and induced pluripotent stem cells (iPSCs), which significantly modulate cancer cell behavior and therapeutic responses. Most of the findings from the co-culture of Michigan Cancer Foundation-7 breast cancer cells and MSC showed the formation of monolayers. Although changes in the plasticity of MSCs and iPSCs caused by other cells and extracellular matrix (ECM) have been extensively researched, the effect of MSCs on cancer stem cell (CSC) aggressiveness is still controversial and contradictory among different research communities. Some researchers have argued that CSCs proliferate more, while others have proposed that cancer spread occurs through dormancy. This highlights the need for further investigation into how these interactions shape cancer aggressiveness. The objective of this review is to explore changes in cancer cell behavior within a 3D microenvironment enriched with MSCs, iPSCs, and ECM components. By describing various MSC and iPSC-derived 3D breast cancer models that replicate tumor biology, we aim to elucidate potential therapeutic targets for breast cancer. A particular focus of this review is the Transwell system, which facilitates understanding how MSCs and iPSCs affect critical processes such as migration, invasion, and angiogenesis. The gradient formed between the two chambers is based on diffusion, as seen in the human body. Once optimized, this Transwell model can serve as a high-throughput screening platform for evaluating various anticancer agents. In the future, primary cell-based and patient-derived 3D organoid models hold promise for advancing personalized medicine and accelerating drug development processes.

The influence of fetal bovine serum concentration on stemness and neuronal differentiation markers in stem cells from human exfoliated deciduous teeth

Dental Stem Cells (DSCs) from discarded teeth are a non-invasive and ethically favorable source with the potential for neurogenesis due to their ectodermal origin. Stem cells from human exfoliated deciduous teeth (SHED) are particularly promising due to their high differentiation potential and relative immaturity compared to other Mesenchymal Stromal Cells (MSCs). Markers like CD56 and CD271 are critical in identifying MSC subpopulations for therapeutic applications because of their roles in neurodevelopment and maintaining stemness. This study investigates how fetal bovine serum (FBS) concentrations affect the expression of CD56 and CD271 in SHED, influencing their stemness and neuronal differentiation potential. SHEDs were isolated from various donors, cultured, and characterized for MSC traits using markers such as CD14, CD19, CD29, CD34, CD45, CD73, CD90, CD105, CD56, and CD271. Culturing SHED in different FBS conditions (standard 15 %, reduced 1 % and 5 %, and FBS-free) showed that lower FBS concentrations increase CD271 and CD56 expression while maintaining the standard MSC immunophenotype. Importantly, the enhanced expression of these markers can be induced even after SHEDs have been expanded in standard FBS concentrations. These findings suggest that FBS concentration can optimize SHED culture conditions, enhancing their suitability for regenerative medicine and tissue engineering applications.

Collagen I Microfiber Promotes Brain Capillary Network Formation in Three-Dimensional Blood-Brain Barrier Microphysiological Systems

BACKGROUND

The blood-brain barrier (BBB) strictly regulates the penetration of substances into the brain, which, although important for maintaining brain homeostasis, may delay drug development because of the difficulties in predicting pharmacokinetics/pharmacodynamics (PKPD), toxicokinetics/toxicodynamics (TKTD), toxicity, safety, and efficacy in the central nervous system (CNS). Moreover, BBB functional proteins show species differences; therefore, humanized in vitro BBB models are urgently needed to improve the predictability of preclinical studies. Recently, international trends in the 3Rs in animal experiments and the approval of the FDA Modernization Act 2.0 have accelerated the application of microphysiological systems (MPSs) in preclinical studies, and in vitro BBB models have become synonymous with BBB-MPSs. Recently, we developed an industrialized humanized BBB-MPS, BBB-NET. In our previous report, we reproduced transferrin receptor (TfR)-mediated transcytosis with high efficiency and robustness, using hydrogels including fibrin and collagen I microfibers (CMFs).

METHODS

We investigated how adding CMFs to the fibrin gel benefits BBB-NETs.

RESULTS

We showed that CMFs accelerate capillary network formation and maturation by promoting astrocyte (AC) survival, and clarified that integrin β1 is involved in the mechanism of CMFs.

CONCLUSIONS

Our data suggest that the quality control (QC) of CMFs is important for ensuring the stable production of BBB-NETs.

Predominant control of PDGF/PDGF receptor signaling in the migration and proliferation of human adipose‑derived stem cells under culture conditions with a combination of growth factors

Human adipose-derived stem cells (hASCs) play important roles in regenerative medicine and tissue engineering. However, their clinical applications are limited because of their instability during cell culture. Platelet lysates (PLTs) contain large amounts of growth factors that are useful for manufacturing cellular products. Platelet-derived growth factor (PDGF) is a major growth factor in PLTs and a potent mitogen in hASCs. To optimize growth conditions, the effects of a combination of growth factors on the promotion of hASC proliferation were investigated. Moreover, PDGF-BB combined with vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF) markedly enhanced the viability of hASCs compared with the effects of PDGF-BB alone. Neither VEGF nor HGF had any effect alone. All growth factor receptor inhibitors inhibited cell proliferation. Wound healing assays revealed that VEGF and HGF stimulated PDGF-dependent cell migration. The effects of these growth factors on the activation of their cognate receptors and signaling enzymes were assessed using immunoblotting. Phosphorylation of PDGF receptor (PDGFR)β, VEGF receptor (VEGFR)2 and MET proto-oncogene and receptor tyrosine kinase was induced by PDGF-BB treatment, and was further increased by treatment with PDGF-BB/VEGF and PDGF-BB/HGF. The levels of phospho-ERK1/2 and phospho-p38MAPK were increased by these treatments in parallel. Furthermore, the expression levels of SRY-box transcription factor 2 and peroxisome proliferator-activated receptor g were increased in PDGF-BB-treated cells, and PDGF-BB played a dominant role in spheroid formation. The findings of the present study highlighted that PDGF/PDGFR signaling played a predominant role in the proliferation and migration of hASCs, and suggested that PDGF was responsible for the efficacy of other growth factors when hASCs were cultured with PLTs.

Emilin2 fosters vascular stability by promoting pericyte recruitment

Angiogenesis, the formation of the new blood vessels from pre-existing vasculature, is an essential process occurring under both normal and pathological conditions, such as inflammation and cancer. This complex process is regulated by several cytokines, growth factors and extracellular matrix components modulating endothelial cell and pericyte function. In this study, we discovered that the extracellular matrix glycoprotein Elastin Microfibril Interfacer 2 (Emilin2) plays a prominent role in pericyte physiology. This work was originally prompted by the observations that tumor-associated vessels from Emilin2-/- mice display less pericyte coverage, impaired vascular perfusion, and reduced drug efficacy, suggesting that Emilin2 could promote vessel maturation and stabilization affecting pericyte recruitment. We found that Emilin2 affects different mechanisms engaged in pericyte recruitment and vascular stabilization. First, human primary endothelial cells challenged with recombinant Emilin2 synthesized and released ∼ 2.1 and 1.2 folds more PDGF-BB and HB-EGF, two cytokines known to promote pericyte recruitment. We also discovered that Emilin2, by directly engaging α5β1 and α6β1 integrins, highly expressed in pericytes, served as an adhesion substrate and haptotactic stimulus for pericytes. Moreover, Emilin2 evoked increased NCadherin expression via the sphingosine-1-phosphate receptor, leading to enhanced vascular stability by fostering interconnection between endothelial cells and pericytes. Finally, restoring pericyte coverage in melanoma and ovarian tumor vessels developed in Emilin2-/- mice improved drug delivery to the tumors. Collectively, our results implicate Emilin2 as a prominent regulator of pericyte function and suggest that Emilin2 expression could represent a promising maker to predict the clinical outcome of patients with melanoma, ovarian, and potentially other forms of cancer.

Renal cancer secretome induces migration of mesenchymal stromal cells

BACKGROUND

Advanced renal cell carcinoma (RCC) is therapeutically challenging. RCC progression is facilitated by mesenchymal stem/stromal cells (MSCs) that exert remarkable tumor tropism. The specific mechanisms mediating MSCs' migration to RCC remain unknown. Here, we aimed to comprehensively analyze RCC secretome to identify MSCs attractants.

METHODS

Conditioned media (CM) were collected from five RCC-derived cell lines (Caki-1, 786-O, A498, KIJ265T and KIJ308T) and non-tumorous control cell line (RPTEC/TERT1) and analyzed using cytokine arrays targeting 274 cytokines in addition to global CM proteomics. MSCs were isolated from bone marrow of patients undergoing standard orthopedic surgeries. RCC CM and the selected recombinant cytokines were used to analyze their influence on MSCs migration and microarray-targeted gene expression. The expression of genes encoding cytokines was evaluated in 100 matched-paired control-RCC tumor samples.

RESULTS

When compared with normal cells, CM from advanced RCC cell lines (Caki-1 and KIJ265T) were the strongest stimulators of MSCs migration. Targeted analysis of 274 cytokines and global proteomics of RCC CM revealed decreased DPP4 and EGF, as well as increased AREG, FN1 and MMP1, with consistently altered gene expression in RCC cell lines and tumors. AREG and FN1 stimulated, while DPP4 attenuated MSCs migration. RCC CM induced MSCs' transcriptional reprogramming, stimulating the expression of CD44, PTX3 and RAB27B. RCC cells secreted hyaluronic acid (HA), a CD44 ligand mediating MSCs' homing to the kidney. AREG emerged as an upregulator of MSCs' transcription.

CONCLUSIONS

Advanced RCC cells secrete AREG, FN1 and HA to induce MSCs migration, while DPP4 loss prevents its inhibitory effect on MSCs homing. RCC secretome induces MSCs' transcriptional reprograming to facilitate their migration. The identified components of RCC secretome represent potential therapeutic targets.

Scaffolds containing GAG-mimetic cellulose sulfate promote TGF-β interaction and MSC Chondrogenesis over native GAGs

Cartilage tissue engineering strategies seek to repair damaged tissue using approaches that include scaffolds containing components of the native extracellular matrix (ECM). Articular cartilage consists of glycosaminoglycans (GAGs) which are known to sequester growth factors. In order to more closely mimic the native ECM, this study evaluated the chondrogenic differentiation of mesenchymal stem cells (MSCs), a promising cell source for cartilage regeneration, on fibrous scaffolds that contained the GAG-mimetic cellulose sulfate. The degree of sulfation was evaluated, examining partially sulfated cellulose (pSC) and fully sulfated cellulose (NaCS). Comparisons were made with scaffolds containing native GAGs (chondroitin sulfate A, chondroitin sulfate C and heparin). Transforming growth factor-beta3 (TGF-β3) sequestration, as measured by rate of association, was higher for sulfated cellulose-containing scaffolds as compared to native GAGs. In addition, TGF-β3 sequestration and retention over time was highest for NaCS-containing scaffolds. Sulfated cellulose-containing scaffolds loaded with TGF-β3 showed enhanced chondrogenesis as indicated by a higher Collagen Type II:I ratio over native GAGs. NaCS-containing scaffolds loaded with TGF-β3 had the highest expression of chondrogenic markers and a reduction of hypertrophic markers in dynamic loading conditions, which more closely mimic in vivo conditions. Studies also demonstrated that TGF-β3 mediated its effect through the Smad2/3 signaling pathway where the specificity of TGF-β receptor (TGF- βRI)-phosphorylated SMAD2/3 was verified with a receptor inhibitor. Therefore, studies demonstrate that scaffolds containing cellulose sulfate enhance TGF-β3-induced MSC chondrogenic differentiation and show promise for promoting cartilage tissue regeneration.

Understanding the impact of bioactive coating materials for human mesenchymal stromal cells and implications for manufacturing

Bioactive materials interact with cells and modulate their characteristics which enable the generation of cell-based products with desired specifications. However, their evaluation and impact are often overlooked when establishing a cell therapy manufacturing process. In this study, we investigated the role of different surfaces for tissue culture including, untreated polystyrene surface, uncoated Cyclic Olefin Polymer (COP) and COP coated with collagen and recombinant fibronectin. It was observed that human mesenchymal stromal cells (hMSCs) expanded on COP-coated plates with different bioactive materials resulted in improved cell growth kinetics compared to traditional polystyrene plates and non-coated COP plates. The doubling time obtained was 2.78 and 3.02 days for hMSC seeded in COP plates coated with collagen type I and recombinant fibronectin respectively, and 4.64 days for cells plated in standard polystyrene treated plates. Metabolite analysis reinforced the findings of the growth kinetic studies, specifically that cells cultured on COP plates coated with collagen I and fibronectin exhibited improved growth as evidenced by a higher lactate production rate (9.38 × 10⁵ and 9.67 × 10⁵ pmol/cell/day, respectively) compared to cells from the polystyrene group (5.86 × 10⁵ pmol/cell/day). This study demonstrated that COP is an effective alternative to polystyrene-treated plates when coated with bioactive materials such as collagen and fibronectin, however COP-treated plates without additional coatings were found not to be sufficient to support cell growth. These findings demonstrate the key role biomaterials play in the cell manufacturing process and the importance of optimising this selection.

Fibrinogen supports self-renewal of mesenchymal stem cells under serum-reduced condition through autophagy activation

Mesenchymal stem cells (MSCs) are somatic stem cells used in cell transplantation therapy for tissue injuries and inflammatory diseases because of their ability to support tissue regeneration and to suppress inflammation. While their applications are expanding, needs for automation of culture procedures with reduction of animal-derived materials to meet stable quality and suppliability are also increasing. On the other hand, the development of molecules that safely support cell adherence and expansion on a variety of interfaces under the serum-reduced culture condition remains a challenge. We report here that fibrinogen enables MSC culture on various materials with low cell adhesion property even under serum-reduced culture conditions. Fibrinogen promoted MSC adhesion and proliferation by stabilizing basic fibroblast growth factor (bFGF), which was secreted in the culture medium by autocrine, and also activated autophagy to suppress cellar senescence. Fibrinogen coating allowed MSCs expansion even on the polyether sulfone membrane that represents very low cell adhesion, and the MSCs showed therapeutic effects in a pulmonary fibrosis model. This study demonstrates that fibrinogen is currently the safest and most widely available extracellular matrix and can be used as a versatile scaffold for cell culture in regenerative medicine.

Engine shutdown: migrastatic strategies and prevention of metastases

Most cancer-related deaths among patients with solid tumors are caused by metastases. Migrastatic strategies represent a unique therapeutic approach to prevent all forms of cancer cell migration and invasion. Because the migration machinery has been shown to promote metastatic dissemination, successful migrastatic therapy may reduce the need for high-dose cytotoxic therapies that are currently used to prevent the risk of metastatic dissemination. In this review we focus on anti-invasive and antimetastatic strategies that hold promise for the treatment of solid tumors. The best targets for migrastatic therapy would be those that are required by all forms of motility, such as ATP availability, mitochondrial metabolism, and cytoskeletal dynamics and cell contractility.

Enhanced PDGFR/Wnt/β-catenin activity of mesenchymal stem cells with high migration ability rescue bone loss of osteoporosis

Osteoporosis is a widespread disease characterized by bone mass loss and microarchitectural deterioration. The significant side effects of clinical drugs make mesenchymal stem cells (MSCs)-based therapy gain increasing focus in the treatment of osteoporosis. MSCs need to migrate to the site of damage and undergo differentiation in order to participate in the subsequent bone repair process. Therefore, the homing ability of MSCs may be related to the repair ability. Here, we proposed a novel method to screen MSCs with high migration capacity and confirmed that these MSCs exhibited higher osteogenic differentiation ability both in vivo and in vitro. Further researches indicated that MSCs with high migration ability could partly rescue the bone loss of ovarectomized (OVX) rats. Higher expression of Platelet-derived growth factors receptor β- (PDGFRβ) and more nuclear transduction of β-catenin in MSCs with high migration ability may be responsible for biological functions. This article may provide a method to improve the efficacy of MSCs-based therapy in the clinic.

Identification of key differential genes in intimal hyperplasia induced by left carotid artery ligation

Background

Intimal hyperplasia is a common pathological process of restenosis following angioplasty, atherosclerosis, pulmonary hypertension, vein graft stenosis, and other proliferative diseases. This study aims to screen for potential novel gene targets and mechanisms related to vascular intimal hyperplasia through an integrated microarray analysis of the Gene Expression Omnibus Database (GEO) database.

Material and Methods

The gene expression profile of the GSE56143 dataset was downloaded from the Gene Expression Omnibus database. Functional enrichment analysis, protein-protein interaction (PPI) network analysis, and the transcription factor (TF)-target gene regulatory network were used to reveal the biological functions of differential genes (DEGs). Furthermore, the expression levels of the top 10 key DEGs were verified at the mRNA and protein level in the carotid artery 7 days after ligation.

Results

A total of 373 DEGs (199 upregulated DEGs and 174 downregulated DEGs) were screened. These DEGs were significantly enriched in biological processes, including immune system process, cell adhesion, and several pathways, which were mainly associated with cell adhesion molecules and the regulation of the actin cytoskeleton. The top 10 key DEGs (Ptprc, Fn1, Tyrobp, Emr1, Itgb2, Itgax, CD44, Ctss, Ly86, and Aif1) acted as key genes in the PPI network. The verification of these key DEGs at the mRNA and protein levels was consistent with the results of the above-mentioned bioinformatics analysis.

Conclusion

The present study identified key genes and pathways involved in intimal hyperplasia induced by carotid artery ligation. These results improved our understanding of the mechanisms underlying the development of intimal hyperplasia and provided candidate targets.

Cell-specific aptamers as potential drugs in therapeutic applications: A review of current progress

Cell-specific aptamers are a promising emerging player in the field of disease therapy. This paper reviews the multidimensional research progress made in terms of their classification, modification, and application. Based on the target location of cell-specific aptamers, it is defined and classified cell-specific aptamers into three groups including aptamers for cell surface markers, aptamers for intracellular components, and aptamers for extracellular components. Moreover, the modification methods of aptamers to achieve improved stability and affinity are concluded. In addition, recent advances in the application of cell-specific aptamers are discussed, mainly focusing on the increasing research attraction of cell state improving helpers and cell recruitment mediators in the improvement of cellular microenvironments to achieve successful disease therapy. This review also highlights 11 types of clinical aptamer drugs. Finally, the challenges and future directions of potential clinical applications are presented. In summary, we believe that cell-specific aptamers are promising drugs in disease therapy.

Orsellinic acid-loaded chitosan nanoparticles in gelatin/nanohydroxyapatite scaffolds for bone formation in vitro

AIM

Orsellinic acid (2,4-Dimethoxy-6-methylbenzoic acid) (OA) is a hydrophobic polyphenolic compound with therapeutic potential, but its impact on actuating osteogenesis remains unknown. The bioavailability of OA is hampered by its hydrophobic nature. This study aimed to fabricate nano-drug delivery system-based scaffolds for OA and test its potential for osteogenesis in vitro.

MATERIALS AND METHODS

OA was loaded into chitosan nanoparticles (nCS + OA) using the ionic gelation technique at different concentrations. nCS + OA were incorporated onto the scaffolds containing gelatin (Gel) and nanohydroxyapatite (nHAp) by the lyophilization method. Biocomposite scaffolds were examined for their physicochemical and material characteristic properties. The effect of OA in the scaffolds for osteoblast differentiation was determined by alizarin red and von Kossa staining at the cellular level and by reverse transcriptase-qPCR and western blot analysis at the molecular level.

KEY FINDINGS

The scaffolds showed excellent physiochemical and material characteristics and remained cyto-friendly to mouse mesenchymal stem cells (mMSCs, C3H10T1/2). The release of OA from Gel/nHAp/nCS scaffolds enhanced the differentiation of mMSCs towards osteoblasts, as observed through cellular and molecular studies. Moreover, the osteogenic potential of OA was mediated by the activation of FAK and ERK signaling pathways through integrins.

SIGNIFICANCE

The inclusion of OA into Gel/nHAp/nCS biocomposite scaffolds at 80 μM concentration promoted osteoblast differentiation via cell adhesion mediated signaling, compared with that shown by Gel/nHAp/nCS alone. Overall, this study identified the potential therapeutic OA containing Gel/nHAp/nCS scaffolds, accelerating its potential for clinical application towards bone regeneration.

Spidroin striped micropattern promotes chondrogenic differentiation of human Wharton's jelly mesenchymal stem cells

Cartilage tissue engineering, particularly micropattern, can influence the biophysical properties of mesenchymal stem cells (MSCs) leading to chondrogenesis. In this research, human Wharton’s jelly MSCs (hWJ-MSCs) were grown on a striped micropattern containing spider silk protein (spidroin) from Argiope appensa. This research aims to direct hWJ-MSCs chondrogenesis using micropattern made of spidroin bioink as opposed to fibronectin that often used as the gold standard. Cells were cultured on striped micropattern of 500 µm and 1000 µm width sizes without chondrogenic differentiation medium for 21 days. The immunocytochemistry result showed that spidroin contains RGD sequences and facilitates cell adhesion via integrin β1. Chondrogenesis was observed through the expression of glycosaminoglycan, type II collagen, and SOX9. The result on glycosaminoglycan content proved that 1000 µm was the optimal width to support chondrogenesis. Spidroin micropattern induced significantly higher expression of SOX9 mRNA on day-21 and SOX9 protein was located inside the nucleus starting from day-7. COL2A1 mRNA of spidroin micropattern groups was downregulated on day-21 and collagen type II protein was detected starting from day-14. These results showed that spidroin micropattern enhances chondrogenic markers while maintains long-term upregulation of SOX9, and therefore has the potential as a new method for cartilage tissue engineering.

Potential Anti-Inflammatory Effects of a New Lyophilized Formulation of the Conditioned Medium Derived from Periodontal Ligament Stem Cells

The mesenchymal stem cells’ (MSCs) secretome includes the bioactive molecules released in the conditioned medium (CM), such as soluble proteins, free nucleic acids, lipids and extracellular vesicles. The secretome is known to mediate some of the beneficial properties related to MSCs, such as anti-inflammatory, anti-apoptotic and regenerative capacities. In this work, we aim to evaluate the anti-inflammatory potential of a new lyophilized formulation of CM derived from human periodontal ligament stem cells (hPDLSCs). With this aim, we treat hPDLSCs with lipopolysaccharide (LPS) and test the anti-inflammatory potential of lyophilized CM (LYO) through the evaluation of wound closure, transcriptomic and immunofluorescence analysis. LPS treatment increased the expression of TLR4 and of genes involved in its signaling and in p38 and NF-κB activation, also increasing the expression of cytokines and chemokines. Interestingly, LYO downregulated the expression of genes involved in Toll-like receptor 4 (TLR-4), nuclear factor kappa light chain enhancer of activated B cells (NF-κB) and p38 signaling. As a consequence, the genes encoding for cytokines and chemokines were also downregulated. Immunofluorescence acquisitions confirmed the downregulation of TLR-4 and NF-κB with the LYO treatment. Moreover, the LYO treatment also increased hPDLSCs’ migration. LYO was demonstrated to contain transforming growth factor (TGF)-β3 and vascular endothelial growth factor (VEGF). These results suggest that LYO represents an efficacious formulation with anti-inflammatory potential and highlights lyophilization as a valid method to produce stable formulations of MSCs’ secretome.

Towards targeting of shared mechanisms of cancer metastasis and therapy resistance

Resistance to therapeutic treatment and metastatic progression jointly determine a fatal outcome of cancer. Cancer metastasis and therapeutic resistance are traditionally studied as separate fields using non-overlapping strategies. However, emerging evidence, including from in vivo imaging and in vitro organotypic culture, now suggests that both programmes cooperate and reinforce each other in the invasion niche and persist upon metastatic evasion. As a consequence, cancer cell subpopulations exhibiting metastatic invasion undergo multistep reprogramming that - beyond migration signalling - supports repair programmes, anti-apoptosis processes, metabolic adaptation, stemness and survival. Shared metastasis and therapy resistance signalling are mediated by multiple mechanisms, such as engagement of integrins and other context receptors, cell-cell communication, stress responses and metabolic reprogramming, which cooperate with effects elicited by autocrine and paracrine chemokine and growth factor cues present in the activated tumour microenvironment. These signals empower metastatic cells to cope with therapeutic assault and survive. Identifying nodes shared in metastasis and therapy resistance signalling networks should offer new opportunities to improve anticancer therapy beyond current strategies, to eliminate both nodular lesions and cells in metastatic transit.

Mesenchymal Stem Cell-Based COVID-19 Therapy: Bioengineering Perspectives

The novel pathogenic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes coronavirus disease 2019 (COVID-19). Mesenchymal stem cells (MSCs) are currently utilized in clinics for pulmonary inflammatory diseases, including acute respiratory distress syndrome and acute lung injury. Given that MSCs offer a promising treatment against COVID-19, they are being used against COVID-19 in more than 70 clinical trials with promising findings. Genetically engineered MSCs offer promising therapeutic options in pulmonary diseases. However, their potential has not been explored yet. In this review, we provide perspectives on the functionally modified MSCs that can be developed and harnessed for COVID-19 therapy. Options to manage the SARS-CoV-2 infection and its variants using various bioengineering tools to increase the therapeutic efficacy of MSCs are highlighted.

Pulling back the curtain: The hidden functions of receptor tyrosine kinases in development

Receptor tyrosine kinases (RTKs) are a conserved superfamily of transmembrane growth factor receptors that drive numerous cellular processes during development and in the adult. Upon activation, multiple adaptors and signaling effector proteins are recruited to binding site motifs located within the intracellular domain of the RTK. These RTK-effector interactions drive subsequent intracellular signaling cascades involved in canonical RTK signaling. Genetic dissection has revealed that alleles of Fibroblast Growth Factor receptors (FGFRs) that lack all canonical RTK signaling still retain some kinase-dependent biological activity. Here we examine how genetic analysis can be used to understand the mechanism by which RTKs drive multiple developmental processes via canonical signaling while revealing noncanonical activities. Recent data from both FGFRs and other RTKs highlight potential noncanonical roles in cell adhesion and nuclear signaling. The data supporting such functions are discussed as are recent technologies that have the potential to provide valuable insight into the developmental significance of these noncanonical activities.

Overcoming Therapy Resistance and Relapse in TNBC: Emerging Technologies to Target Breast Cancer-Associated Fibroblasts

Breast cancer is the most diagnosed cancer and is the leading cause of cancer mortality in women. Triple-negative breast cancer (TNBC) is an aggressive form of breast cancer. Often, TNBC is not effectively treated due to the lack of specificity of conventional therapies and results in relapse and metastasis. Breast cancer-associated fibroblasts (BCAFs) are the predominant cells that reside in the tumor microenvironment (TME) and regulate tumorigenesis, progression and metastasis, and therapy resistance. BCAFs secrete a wide range of factors, including growth factors, chemokines, and cytokines, some of which have been proved to lead to a poor prognosis and clinical outcomes. This TME component has been emerging as a promising target due to its crucial role in cancer progression and chemotherapy resistance. A number of therapeutic candidates are designed to effectively target BCAFs with a focus on their tumor-promoting properties and tumor immune response. This review explores various agents targeting BCAFs in TNBC, including small molecules, nucleic acid-based agents, antibodies, proteins, and finally, nanoparticles.

Bioinformatic Analyses and Experimental Verification Reveal that High FSTL3 Expression Promotes EMT via Fibronectin-1/α5β1 Interaction in Colorectal Cancer

Background: Colorectal cancer (CRC) is a typical cancer prevalent worldwide. Despite the conventional treatments, CRC has a poor prognosis due to relapse and metastasis. Moreover, there is a dearth of sensitive biomarkers for predicting prognosis in CRC.

Methods: This study used a bioinformatics approach combining validation experiments to examine the value of follistatin-like 3 (FSTL3) as a prognostic predictor and therapeutic target in CRC.

Results:FSTL3 was remarkably upregulated in the CRC samples. FSTL3 overexpression was significantly associated with a poor prognosis. FSTL3 was found to activate the epithelial-mesenchymal transition by promoting the binding of FN1 to α5β1. FSTL3 expression was also positively correlated with the abundance of the potent immunosuppressors, M2 macrophages.

Conclusion:FSTL3 overexpression affects CRC prognosis and thus, FSTL3 can be a prognostic biomarker and therapeutic target with potential applications in CRC.

Platelet-Derived Growth Factor Induces SASP-Associated Gene Expression in Human Multipotent Mesenchymal Stromal Cells but Does Not Promote Cell Senescence

Activation of multipotent mesenchymal stromal cells (MSCs) is a central part of tissue response to damage. Platelet-derived growth factor (PDGF-BB), which is abundantly released in the damaged area, potently stimulates the proliferation and migration of MSCs. Recent evidence indicates that tissue injury is associated with the accumulation of senescent cells, including ones of MSC origin. Therefore, we hypothesized that PDGF-BB induces MSC senescence. To evaluate mechanisms of early activation of MSCs by PDGF-BB, we performed transcriptome profiling of human MSCs isolated from adipose tissue after exposure to PDGF-BB for 12 and 24 h. We demonstrated that PDGF-BB induced the expression of several genes encoding the components of senescence-associated secretory phenotype (SASP) in MSCs such as plasminogen activator inhibitor-1 (PAI-1), urokinase-type plasminogen activator and its receptor (uPA and uPAR), and some matrix metalloproteases. However, further experimental validation of transcriptomic data clearly indicated that PDGF-BB exerted mitogenic and pro-migratory effects on MSCs, and augmented their pro-angiogenic activity, but did not significantly stimulate MSC senescence.

Bidirectional relationship between cardiac extracellular matrix and cardiac cells in ischemic heart disease

Ischemic heart diseases (IHDs), including myocardial infarction and cardiomyopathies, are a leading cause of mortality and morbidity worldwide. Cardiac-derived stem and progenitor cells have shown promise as a therapeutic for IHD but are limited by poor cell survival, limited retention, and rapid washout. One mechanism to address this is to encapsulate the cells in a matrix or three-dimensional construct, so as to provide structural support and better mimic the cells' physiological microenvironment during administration. More specifically, the extracellular matrix (ECM), the native cellular support network, has been a strong candidate for this purpose. Moreover, there is a strong consensus that the ECM and its residing cells, including cardiac stem cells, have a constant interplay in response to tissue development, aging, disease progression, and repair. When externally stimulated, the cells and ECM work together to mutually maintain the local homeostasis by initially altering the ECM composition and stiffness, which in turn alters the cellular response and behavior. Given this constant interplay, understanding the mechanism of bidirectional cell-ECM interaction is essential to develop better cell implantation matrices to enhance cell engraftment and cardiac tissue repair. This review summarizes current understanding in the field, elucidating the signaling mechanisms between cardiac ECM and residing cells in response to IHD onset. Furthermore, this review highlights recent advances in native ECM-mimicking cardiac matrices as a platform for modulating cardiac cell behavior and inducing cardiac repair.

Regulatory mechanism of oral mucosal rete peg formation

Rete pegs are finger-like structures that are formed during the development and wound healing process of the skin and oral mucosa, and they provide better mechanical resistance and nutritional supply between the epithelium and dermis. An increasing number of studies have shown that rete pegs have physiological functions, such as resisting bacterial invasion, body fluid loss, and other harmful changes, which indicate that rete pegs are important structures in natural skin and oral mucosa. Although a great deal of progress has been made in scaffold materials and construction methods for tissue-engineered skin and oral mucosa in recent years, construction of the oral mucosa with functional rete pegs remains a major challenge. In this review, we summarized current research on the progress on formation of rete pegs in human oral mucosa as well as its molecular basis and regulatory mechanism, which might provide new ideas for functional construction of tissue-engineered skin and oral mucosa.

Key Roles of RGD-Recognizing Integrins During Cardiac Development, on Cardiac Cells, and After Myocardial Infarction

Cardiac cells interact with the extracellular matrix (ECM) proteins through integrin mechanoreceptors that control many cellular events such as cell survival, apoptosis, differentiation, migration, and proliferation. Integrins play a crucial role in cardiac development as well as in cardiac fibrosis and hypertrophy. Integrins recognize oligopeptides present on ECM proteins and are involved in three main types of interaction, namely with collagen, laminin, and the oligopeptide RGD (Arg-Gly-Asp) present on vitronectin and fibronectin proteins. To date, the specific role of integrins recognizing the RGD has not been addressed. In this review, we examine their role during cardiac development, their role on cardiac cells, and their upregulation during pathological processes such as heart fibrosis and hypertrophy. We also examine their role in regenerative and angiogenic processes after myocardial infarction (MI) in the peri-infarct area. Specific targeting of these integrins may be a way of controlling some of these pathological events and thereby improving medical outcomes.

Integrin α5β1 Mediated Cellular Reorganization in Human Mesenchymal Stem Cells During Neuronal Differentiation

BACKGROUND/AIM

Mesenchymal stem cells (MSCs) have been widely used for yielding neurons in culture to study nervous system pathologies and develop regenerative approaches. In this study, cellular rearrangements of human MSCs related to the expression of the fibronectin common receptor integrin α5β1 and its cell surface localization during neuronal differentiation, were examined.

MATERIALS AND METHODS

Proliferation kinetics of neuronal induced hMSCs (hMd-Neurons) were quantified by BrdU assay, and hMd-Neurons were immunostained for neuronal marker expression. Additionally, cDNA and protein samples were collected at different time points for integrin α5β1 expression analysis.

RESULTS

Endogenous integrin α5β1 expression was significantly upregulated by day 6 and maintained until day 12. Cell surface localization of α5β1 integrin was increased by day 6; the integrin was internalized into the cytosol by day 12.

CONCLUSION

Integrin dynamics around day 6 of differentiation might be involved in neuronal differentiation and maturation or specification of hMd-Neurons.

Conditions Mimicking the Cancer Microenvironment Modulate the Functional Outcome of Human Chorionic Villus Mesenchymal Stem/Stromal Cells in vitro

Mesenchymal stem/stromal cells isolated from chorionic villi of human term placentae (CV-MSCs) possess unique biological characters. They exhibit self-renewal, directional migration, differentiation, and immunomodulatory effects on other cell lineages, by virtue of which they can be utilized as therapeutic carriers, for drug targeting, and therapy. Tumors display characteristic features of a damaged tissue microenvironment, which is saturated with conditions such as hypoxia, sustained inflammation, and increased oxidative stress. CV-MSCs function normally in a high oxidative stress environment induced by hydrogen peroxide (H₂O₂) and glucose and also protect endothelial cells from their damaging effects. For their therapeutic applications in a disease like cancer, it is necessary to ascertain the effects of tumor microenvironment on their functional outcome. In this study, we investigated the functional activities, of CV-MSCs in response to conditioned media (CM) obtained from the culture of breast cancer cell line MDA-231 (CM-MDA231). CV-MSCs were exposed to CM-MDA231 for different spatio-temporal conditions, and their biological functions as well as modulation in gene expression were evaluated. Effect of CM-MDA231 on factors responsible for changes in functional outcome were also investigated at the protein levels. CV-MSCs exhibited significant reduction in proliferation but increased adhesion and migration after CM-MDA231 treatment. Interestingly, there was no change in their invasion potential. CM-MDA231 treatment modulated expression of various genes involved in important cellular events including, integration, survival, message delivery and favorable outcome after transplantation. Analysis of pathways related to cell cycle regulation revealed significant changes in the expression of p53, and increased phosphorylation of Retinoblastoma (Rb) and Checkpoint Kinase 2 in CV-MSCs treated with CM-MDA231. To summarize, these data reveal that CV-MSCs retain the ability to survive, adhere, and migrate after sustained treatment with CM-MDA231, a medium that mimics the cancer microenvironment. These properties of CV-MSCs to withstand the inflammatory tumor like microenvironment prove that they may make useful candidate in a stem cell based therapy against cancer. However, further pre-clinical studies are needed to validate their therapeutic usage.

Improved response of human gingival fibroblasts to titanium coated with micro-/nano-structured tantalum

OBJECTIVES

This study aims to evaluate the ability of tantalum-coated titanium to improve human gingival fibroblasts' adhesion, viability, proliferation, migration performance, and the potential molecular mechanisms.

MATERIALS AND METHODS

Titanium plates were divided into two groups: (1) no coating (Ti, control), (2) Tantalum-coated titanium (Ta-coated Ti). All samples were characterized by scanning electronic microscopy, surface roughness, and hydrophilicity. Fibroblasts' performance were analyzed by attached cell number at 1 h, 4 h, and 24 h, morphology at 1 h and 4 h, viability at 1 day, 3 days, 5 days, and 7 days, recovery after wounding at 6 h, 12 h, and 24 h. RT-PCR, western blot were applied to detect attachment-related genes' expression and protein synthesis at 4 h and 24 h. Student's t test was used for statistical analysis.

RESULTS

Tantalum-coated titanium demonstrates a layer of homogeneously distributed nano-grains with mean diameter of 25.98 (± 14.75) nm. It was found that after tantalum deposition, human gingival fibroblasts (HGFs) adhesion, viability, proliferation, and migration were promoted in comparison to the control group. An upregulated level of Integrin β1 and FAK signaling was also detected, which might be the underlying mechanism.

CONCLUSION

In the present study, adhesion, viability, proliferation, migration of human gingival fibroblasts are promoted on tantalum-coated titanium, upregulated integrin β1 and FAK might contribute to its superior performance, indicating tantalum coating can be applied in transmucosal part of dental implant.

CLINICAL SIGNIFICANCE

Tantalum deposition on titanium surfaces can promote human gingival fibroblast adhesion, accordingly forming a well-organized soft tissue sealing and may contribute to a successful osseointegration.

IL-1β mediated nanoscale surface clustering of integrin α5β1 regulates the adhesion of mesenchymal stem cells

Clinical use of human mesenchymal stem cells (hMSCs) is limited due to their rapid clearance, reducing their therapeutic efficacy. The inflammatory cytokine IL-1β activates hMSCs and is known to enhance their engraftment. Consequently, understanding the molecular mechanism of this inflammation-triggered adhesion is of great clinical interest to improving hMSC retention at sites of tissue damage. Integrins are cell-matrix adhesion receptors, and clustering of integrins at the nanoscale underlies cell adhesion. Here, we found that IL-1β enhances adhesion of hMSCs via increased focal adhesion contacts in an α5β1 integrin-specific manner. Further, through quantitative super-resolution imaging we elucidated that IL-1β specifically increases nanoscale integrin α5β1 availability and clustering at the plasma membrane, whilst conserving cluster area. Taken together, these results demonstrate that hMSC adhesion via IL-1β stimulation is partly regulated through integrin α5β1 spatial organization at the cell surface. These results provide new insight into integrin clustering in inflammation and provide a rational basis for design of therapies directed at improving hMSC engraftment.

Differential alternative splicing between hepatocellular carcinoma with normal and elevated serum alpha-fetoprotein

BACKGROUND

Serum alpha-fetoprotein (AFP) is the approved serum marker for hepatocellular carcinoma (HCC) screening. However, not all HCC patients show high (≥ 20 ng/mL) serum AFP, and the molecular mechanisms of HCCs with normal (< 20 ng/mL) serum AFP remain to be elucidated. Therefore, we aimed to identify biological features of HCCs with normal serum AFP by investigating differential alternative splicing (AS) between HCCs with normal and high serum AFP.

METHODS

We performed a genome-wide survey of AS events in 249 HCCs with normal (n = 131) and high (n = 118) serum AFP levels using RNA-sequencing data obtained from The Cancer Genome Atlas.

RESULTS

In group comparisons of RNA-seq profiles from HCCs with normal and high serum AFP levels, 161 differential AS events (125 genes; ΔPSI > 0.05, FDR < 0.05) were identified to be alternatively spliced between the two groups. Those genes were enriched in cell migration or proliferation terms such as "the cell migration and growth-cone collapse" and "regulation of insulin-like growth factor (IGF) transport and uptake by IGF binding proteins". Most of all, two AS genes (FN1 and FAM20A) directly interact with AFP; these relate to the regulation of IGF transport and post-translational protein phosphorylation. Interestingly, 42 genes and 27 genes were associated with gender and vascular invasion (VI), respectively, but only eighteen genes were significant in survival analysis. We especially highlight that FN1 exhibited increased differential expression of AS events (ΔPSI > 0.05), in which exons 25 and 33 were more frequently skipped in HCCs with normal (low) serum AFP compared to those with high serum AFP. Moreover, these events were gender and VI dependent.

CONCLUSION

We found that AS may influence the regulation of transcriptional differences inherent in the occurrence of HCC maintaining normal rather than elevated serum AFP levels.

Nanoscale Molecular Quantification of Stem Cell-Hydrogel Interactions

A common approach to tailoring synthetic hydrogels for regenerative medicine applications involves incorporating RGD cell adhesion peptides, yet assessing the cellular response to engineered microenvironments at the nanoscale remains challenging. To date, no study has demonstrated how RGD concentration in hydrogels affects the presentation of individual cell surface receptors. Here we studied the interaction between human mesenchymal stem cells (hMSCs) and RGD-functionalized poly(ethylene glycol) hydrogels, by correlating macro- and nanoscale single-cell interfacial quantification techniques. We quantified RGD unbinding forces on a synthetic hydrogel using single cell atomic force spectroscopy, revealing that short-term binding of hMSCs was sensitive to RGD concentration. We also performed direct stochastic optical reconstruction microscopy (dSTORM) to quantify the molecular interactions between integrin α5β1 and a biomaterial, unexpectedly revealing that increased integrin clustering at the hydrogel-cell interface correlated with fewer available RGD binding sites. Our complementary, quantitative approach uncovered mechanistic insights into specific stem cell-hydrogel interactions, where dSTORM provides nanoscale sensitivity to RGD-dependent differences in cell surface localization of integrin α5β1. Our findings reveal that it is possible to precisely determine how peptide-functionalized hydrogels interact with cells at the molecular scale, thus providing a basis to fine-tune the spatial presentation of bioactive ligands.

Review of Integrin-Targeting Biomaterials in Tissue Engineering

The ability to direct cell behavior has been central to the success of numerous therapeutics to regenerate tissue or facilitate device integration. Biomaterial scientists are challenged to understand and modulate the interactions of biomaterials with biological systems in order to achieve effective tissue repair. One key area of research investigates the use of extracellular matrix-derived ligands to target specific integrin interactions and induce cellular responses, such as increased cell migration, proliferation, and differentiation of mesenchymal stem cells. These integrin-targeting proteins and peptides have been implemented in a variety of different polymeric scaffolds and devices to enhance tissue regeneration and integration. This review first presents an overview of integrin-mediated cellular processes that have been identified in angiogenesis, wound healing, and bone regeneration. Then, research utilizing biomaterials are highlighted with integrin-targeting motifs as a means to direct these cellular processes to enhance tissue regeneration. In addition to providing improved materials for tissue repair and device integration, these innovative biomaterials provide new tools to probe the complex processes of tissue remodeling in order to enhance the rational design of biomaterial scaffolds and guide tissue regeneration strategies.

Inflammatory Cytokines Alter Mesenchymal Stem Cell Mechanosensing and Adhesion on Stiffened Infarct Heart Tissue After Myocardial Infarction

Mesenchymal stem cell (MSC) transplantation has demonstrated its potential in repairing infarct heart tissue and recovering heart function after myocardial infarction (MI). However, its therapeutic effect is still limited due to poor MSC engraftment at the injury site whose tissue stiffness and local inflammation both dynamically and rapidly change after MI. Whether and how inflammatory cytokines could couple with stiffness change to affect MSC engraftment in the infarct zone still remain unclear. In this study, we characterized dynamic stiffness changes of and inflammatory cytokine expression in the infarct region of rat heart within a month after MI. We found that the tissue stiffness of the heart tissue gradually increased and peaked 21 days after MI along with the rapid upregulation of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-1β (IL-1β) in the first 3 days, followed by a sharp decline. We further demonstrated in vitro that immobilized inflammatory cytokine IL-6 performed better than the soluble form in enhancing MSC adhesion to stiffened substrate through IL-6/src homology 2 (SH2) domain-containing tyrosine phosphatase-2 (SHP2)/integrin signaling axis. We also confirmed such mechano-immune coupling of tissue stiffness and inflammatory cytokines in modulating MSC engraftment in the rat heart after MI in vivo. Our study provides new mechanistic insights of mechanical–inflammation coupling to improve MSC mechanosensing and adhesion, potentially benefiting MSC engraftment and its clinical therapy for MI.

Feeder-free generation and transcriptome characterization of functional mesenchymal stromal cells from human pluripotent stem cells

Induced mesenchymal stromal cells (iMSCs) derived from human pluripotent stem cells (PSCs) are attractive cells for regenerative medicine. However, the transcriptome of iMSCs and signature genes that can distinguish MSCs from fibroblasts and other cell types are rarely explored. In this study, we reported an optimized feeder-free method for the generation of iMSCs from human pluripotent stem cells. These iMSCs display a typical MSC morphology, express classic MSC markers (CD29, CD44, CD73, CD90, CD105, CD166), are negative for lymphocyte markers (CD11b, CD14, CD31, CD34, CD45, HLA-DR), and are potent for osteogenic and chondrogenic differentiation. Using genome-wide transcriptome profiling, we created an easily accessible transcriptome reference for the process of differentiating PSCs into iMSCs. The iMSC transcriptome reference revealed clear patterns in the silencing of pluripotency genes, activation of lineage commitment genes, and activation of mesenchymal genes during iMSC generation. All previously known positive and negative markers for MSCs were confirmed by our iMSC transcriptomic reference, and most importantly, gene classification and time course analysis identified 52 genes including FN1, TGFB1, TAGLN and SERPINE1, which showed significantly higher expression in MSCs (over 3 folds) than fibroblasts and other cell types. Taken together, these results provide a useful method and important resources for developing and understanding iMSCs in regenerative medicine.

Effects of carbon and nitrogen plasma immersion ion implantation on bioactivity of zirconia

Zirconia is considered the most promising alternative material to titanium implants. However, zirconia is a biologically inert material and its surface modification is essential to obtain efficient osseointegration. Plasma immersion ion implantation (PIII) is a controllable and flexible approach that constructs functional groups on the surface of biomaterials and enhances osteogenic ability of host osteoclast cells. Zirconia disks were randomly divided into 4 groups (n = 50/group): (1) Blank, (2) C60N0, (3) C60N6, and (4) C60N18. Carbon and nitrogen plasma immersion ion implantation on zirconia (C and N₂-PIII) surface modification was completed with the corresponding parameters. When zirconia was modified by carbon and nitrogen plasma implantation, a new chemical structure was formed on the material surface while the surface roughness of the material remained unaltered. The nitrogen-containing functional groups with high potential were introduced but the bulk crystal structure of zirconia was not changed, indicating that the stability of zirconia was not affected. In vitro data showed that zirconia with high surface potential promoted adhesion, proliferation, and osteogenic differentiation of BMSCs. C60N6 was found to be superior to the other groups. Our results demonstrate that a zirconia surface modified by C and N₂-PIII can introduce desirable nitrogen functional groups and create a suitable extracellular environment to promote BMSCs biological activity. Taken together, these results suggest that C and N₂-PIII modified zirconia is a promising material for use in the field of medical implantation.

Zirconia is considered the most promising alternative material to titanium implants.

Assessment of the effect of platelet rich plasma on the healing of operated sacrococcygeal pilonidal sinus by lay-open technique: a randomized clinical trial

Background

Sacrococcygeal pilonidal sinus disease (PSD) is an infection of the skin and subcutaneous tissue at the upper part of the natal cleft of the buttocks. Excision and healing by granulation “lay-open” method is still more preferable than other methods of midline closure or using flaps but the healing time is lengthy. The present study was performed to assess the healing promotion effect of platelet-rich plasma (PRP) on the pilonidal sinus wounds treated by the lay-open method.

Methods

One hundred patients suffering from PSD were randomly divided into two groups, they were treated by the lay-open method, at General surgery department, Kafr El-Sheik University hospital, Egypt, during the period from December 2018 to December 2019. Group (A) was adopted the regular dressing postoperatively, while group (B) was treated with PRP injection into the wound at 4 and 12 postoperative days.

Results

Accelerated rate of wound healing was detected in group (B) in day 10, with a significant difference detected in days 15, 20, 25 and 30 postoperative, with a mean time of complete healing 45 ± 2.6 days in group B, while it was 57 ± 2.4 days in group A with a p-value of 0.001 which indicates considerable effect in the treated group.

Conclusions

PRP injection is an effective new technique in accelerating the healing of pilonidal wound after surgery, with a significant decrease in post-operative pain, complications and an early return to work.

Trial registration

retrospectively registered. Trial registration number: 12/35/1016 issued on December 2018 from the Institution Review Board at Kafr El Sheikh University. ClinicalTrials.gov identifier: NCT04430413

Efficient Isolation and Enrichment of Mesenchymal Stem Cells from Human Embryonic Stem Cells by Utilizing the Interaction between Integrin α5β1 and Fibronectin

Human pluripotent stem cells (hPSCs) are a potent source of clinically relevant mesenchymal stem cells (MSCs) that confer functional and structural benefits in cell therapy and tissue regeneration. Obtaining sufficient numbers of MSCs in a short period of time and enhancing the differentiation potential of MSCs can be offered the potential to improve the regenerative activity of MSCs therapy. In addition, the underlying processes in the isolation and derivation of MSCs from hPSCs are still poorly understood and controlled. To overcome these clinical needs, an efficient and simplified technique on the isolation of MSCs from spontaneously differentiated human embryonic stem cells (hESCs) via integrin α5β1 (fibronectin (FN) receptor)-to-FN interactions (hESC-FN-MSCs) is successfully developed. It is demonstrated that hESC-FN-MSCs exhibit a typical MSC surface phenotype, cellular morphology, with the whole transcriptome similar to conventional adult MSCs; but show higher proliferative capacity, more efficient trilineage differentiation, enhanced cytokine secretion, and attenuated cellular senescence. In addition, the therapeutic potential and regenerative capacity of the isolated hESC-FN-MSCs are confirmed by in vitro and in vivo multilineage differentiation. This novel method will be useful in the generation of abundant amounts of clinically relevant MSCs for stem cell therapeutics and regenerative medicine.

Novel fibrin-fibronectin matrix accelerates mice skin wound healing

Plasma fibrinogen (F1) and fibronectin (pFN) polymerize to form a fibrin clot that is both a hemostatic and provisional matrix for wound healing. About 90% of plasma F1 has a homodimeric pair of γ chains (γγF1), and 10% has a heterodimeric pair of γ and more acidic γ' chains (γγ'F1). We have synthesized a novel fibrin matrix exclusively from a 1:1 (molar ratio) complex of γγ'F1 and pFN in the presence of highly active thrombin and recombinant Factor XIII (rFXIIIa). In this matrix, the fibrin nanofibers were decorated with pFN nanoclusters (termed γγ'F1:pFN fibrin). In contrast, fibrin made from 1:1 mixture of γγF1 and pFN formed a sporadic distribution of "pFN droplets" (termed γγF1+pFN fibrin). The γγ'F1:pFN fibrin enhanced the adhesion of primary human umbilical vein endothelium cells (HUVECs) relative to the γγF1+FN fibrin. Three dimensional (3D) culturing showed that the γγ'F1:pFN complex fibrin matrix enhanced the proliferation of both HUVECs and primary human fibroblasts. HUVECs in the 3D γγ'F1:pFN fibrin exhibited a starkly enhanced vascular morphogenesis while an apoptotic growth profile was observed in the γγF1+pFN fibrin. Relative to γγF1+pFN fibrin, mouse dermal wounds that were sealed by γγ'F1:pFN fibrin exhibited accelerated and enhanced healing. This study suggests that a 3D pFN presentation on a fibrin matrix promotes wound healing.

Bone mesenchymal stem cells are recruited via CXCL8-CXCR2 and promote EMT through TGF-β signal pathways in oral squamous carcinoma

OBJECTIVES

Bone mesenchymal stem cells (BMSCs) play critical roles in tumour microenvironment. However, molecular mechanisms of how BMSCs to be recruited and effect subsequent tumour progression are poorly understood in oral squamous cell carcinoma (OSCC).

MATERIALS AND METHODS

The distribution of CXCL8 was detected by immunohistochemical staining in OSCC tissues. The chemotaxis of conditioned media from different epithelial cells to BMSCs was examined by trans-well assay. Real-time quantitative PCR (qPCR) and ELISA were used to detect the expression of related cytokines and chemokine receptors. The migration of BMSCs was observed in BALB/c nude mice. The roles of BMSCs in proliferation, migration and invasion of OSCC were detected by CCK-8, flow cytometry and trans-well assay. Epithelial-mesenchymal transition (EMT)-related markers were analysed by qPCR and Western blot in vitro, and growth was evaluated in BALB/c nude mice using subcutaneously implanted OSCC in nude mouse model in vivo.

RESULTS

Using OSCC, we show CXCL8, secreted by OSCC, binds to exclusively CXCR2 in BMSCs to facilitate migration of BMSCs to OSCC. TGF-β secreted by BMSCs subsequently induces EMT of OSCC to promote their proliferation, migration and infiltration. We also showed that the Ras/Raf/Erk axis plays a critical role in tumour progression.

CONCLUSIONS

Our results provide the molecular basis for BMSC recruitment into tumours, and how this process leads to tumour progression and leads us to develop a novel OSCC treatment target.

Adhesion and growth factor receptor crosstalk mechanisms controlling cell migration

Cell migration requires cells to sense and interpret an array of extracellular signals to precisely co-ordinate adhesion dynamics, local application of mechanical force, polarity signalling and cytoskeletal dynamics. Adhesion receptors and growth factor receptors (GFRs) exhibit functional and signalling characteristics that individually contribute to cell migration. Integrins transmit bidirectional mechanical forces and transduce long-range intracellular signals. GFRs are fast acting and highly sensitive signalling machines that initiate signalling cascades to co-ordinate global cellular processes. Syndecans are microenvironment sensors that regulate GTPases to control receptor trafficking, cytoskeletal remodelling and adhesion dynamics. However, an array of crosstalk mechanisms exists, which co-ordinate and integrate the functions of the different receptor families. Here we discuss the nature of adhesion receptor and GFR crosstalk mechanisms. The unifying theme is that efficient cell migration requires precise spatial and temporal co-ordination of receptor crosstalk. However, a higher order of complexity emerges; whereby multiple crosstalk mechanisms are integrated and subject to both positive and negative feedbacks. Exquisite and sensitive control of these mechanisms ensures that mechanical forces and pro-migratory signals are triggered in the right place and at the right time during cell migration. Finally, we discuss the challenges, and potential therapeutic benefits, associated with deciphering this complexity.

Small proline-rich repeat 3 is a novel coordinator of PDGFRβ and integrin β1 crosstalk to augment proliferation and matrix synthesis by cardiac fibroblasts

Nearly 6 million Americans suffer from heart failure. Increased fibrosis contributes to functional decline of the heart that leads to heart failure. Previously, we identified a mechanosensitive protein, small proline‐rich repeat 3 (SPRR3), in vascular smooth muscle cells of atheromas. In this study, we demonstrate SPRR3 expression in cardiac fibroblasts which is induced in activated fibroblasts following pressure‐induced heart failure. Sprr3 deletion in mice showed preserved cardiac function and reduced interstitial fibrosis in vivo and reduced fibroblast proliferation and collagen expression in vitro. SPRR3 loss resulted in reduced activation of Akt, FAK, ERK, and p38 signaling pathways, which are coordinately regulated by integrins and growth factors. SPRR3 deletion did not impede integrin‐associated functions including cell adhesion, migration, or contraction. SPRR3 loss resulted in reduced activation of PDGFRβ in fibroblasts. This was not due to the reduced PDGFRβ expression levels or decreased binding of the PDGF ligand to PDGFRβ. SPRR3 facilitated the association of integrin β1 with PDGFRβ and subsequently fibroblast proliferation, suggesting a role in PDGFRβ‐Integrin synergy. We postulate that SPRR3 may function as a conduit for the coordinated activation of PDGFRβ by integrin β1, leading to augmentation of fibroblast proliferation and matrix synthesis downstream of biomechanical and growth factor signals.

Preconditioning of Human Decidua Basalis Mesenchymal Stem/Stromal Cells with Glucose Increased Their Engraftment and Anti-diabetic Properties

Background:

Mesenchymal stem/stromal cells (MSCs) from the decidua basalis (DBMSCs) of the human placenta have important functions that make them potential candidates for cellular therapy. Previously, we showed that DBMSC functions do not change significantly in a high oxidative stress environment, which was induced by hydrogen peroxide (H₂O₂) and immune cells. Here, we studied the consequences of glucose, another oxidative stress inducer, on the phenotypic and functional changes in DBMSCs.

Methods:

DBMSCs were exposed to a high level of glucose, and its effect on DBMSC phenotypic and functional properties was determined. DBMSC expression of oxidative stress and immune molecules after exposure to glucose were also identified.

Results:

Conditioning of DBMSCs with glucose improved their adhesion and invasion. Glucose also increased DBMSC expression of genes with survival, proliferation, migration, invasion, anti-inflammatory, anti-chemoattractant and antimicrobial properties. In addition, DBMSC expression of B7H4, an inhibitor of T cell proliferation was also enhanced by glucose. Interestingly, glucose modulated DBMSC expression of genes involved in insulin secretion and prevention of diabetes.

Conclusion:

These data show the potentially beneficial effects of glucose on DBMSC functions. Preconditioning of DBMSCs with glucose may therefore be a rational strategy for increasing their therapeutic potential by enhancing their engraftment efficiency. In addition, glucose may program DBMSCs into insulin producing cells with ability to counteract inflammation and infection associated with diabetes. However, future in vitro and in vivo studies are essential to investigate the findings of this study further.

Electronic supplementary material

The online version of this article (10.1007/s13770-020-00239-7) contains supplementary material, which is available to authorized users.

Framing cancer progression: influence of the organ- and tumour-specific matrisome

The extracellular matrix (ECM) plays a crucial role in regulating organ homeostasis. It provides mechanical and biochemical cues directing cellular behaviour and, therefore, has control over the progression of diseases such as cancer. Recent efforts have greatly enhanced our knowledge of the protein composition of the ECM and its regulators, the so-called matrisome, in healthy and cancerous tissues; yet, an overview of the common signatures and organ-specific ECM in cancer is missing. Here, we address this by taking a detailed approach to review why cancer grows in certain organs, and focus on the influence of the matrisome at primary and metastatic tumour sites. Our in-depth and comprehensive review of the current literature and general understanding identifies important commonalities and distinctions, providing insight into the biology of metastasis, which could pave the way to improve future diagnostics and therapies.