Redifferentiation of genetically modified dedifferentiated chondrocytes in a microcavitary hydrogel.

OBJECTIVES: We genetically modified dedifferentiated chondrocytes (DCs) using lentiviral vectors and adenoviral vectors encoding TGF-ß3 (referred to as transgenic groups below) and encapsulated these DCs in the microcavitary hydrogel and investigated the combinational effect on redifferentiation of the genetically manipulated DCs. RESULTS: The Cell Counting Kit-8 data indicated that both transgenic groups exhibited significantly higher cell viability in the first week but inferior cell viability in the subsequent timepoints compared with those of the control group. Real-time polymerase chain reaction and western blot analysis results demonstrated that both transgenic groups had a better effect on redifferentiation to some extent, as evidenced by higher expression levels of chondrogenic genes, suggesting the validity of combination with transgenic DCs and the microcavitary hydrogel on redifferentiation. Although transgenic DCs with adenoviral vectors presented a superior extent of redifferentiation, they also expressed greater levels of the hypertrophic gene type X collagen. It is still worth further exploring how to deliver TGF-ß3 more efficiently and optimizing the appropriate parameters, including concentration and duration. CONCLUSIONS: The results demonstrated the better redifferentiation effect of DCs with the combinational use of transgenic TGF-ß3 and a microcavitary alginate hydrogel and implied that DCs would be alternative seed cells for cartilage tissue engineering due to their easily achieved sufficient cell amounts through multiple passages and great potential to redifferentiate to produce cartilaginous extracellular matrix.

Role of TGF-ß3 in modulating inflammatory responses and wound healing processes in ischemic ulcers in atherosclerotic patients.

Ischemic ulcers pose a multifaceted clinical dilemma for patients with atherosclerosis, frequently compounded by suboptimal wound healing mechanisms. The dual function of Transforming Growth Factor Beta 3 (TGF-ß3) in ischemic ulcer healing is not fully comprehended, despite its involvement in modulating inflammatory responses and tissue regeneration. The main aim of this investigation was to clarify the functions and mechanisms by which TGF-ß3 regulates inflammatory responses and promotes wound healing in patients with ischemic ulcers who have atherosclerosis. Between August 2022 and November 2023, this cross-sectional investigation was conducted on 428 patients diagnosed with atherosclerotic ischemic ulcers in Haikou, China. The expression and function of TGF-ß3 were examined throughout the different stages of wound healing, including inflammation, proliferation and remodelling. In addition to documenting patient demographics and ulcer characteristics, an analysis was conducted on biopsy samples to determine the expression of TGF-ß3, pro-inflammatory and anti-inflammatory markers. A subset of patients were administered topical TGF-ß3 in order to evaluate its therapeutic effects. The expression pattern of TGF-ß3 was found to be stage-dependent and significant, exhibiting increased levels during the phase of inflammation and reduced activity in subsequent phases. TGF-ß3 levels were found to be greater in ulcers that were larger and deeper, especially in inflammatory phase. TGF-ß3 applied topically induced discernible enhancement in ulcer healing parameters, such as reduction in ulcer depth and size. The therapeutic significance of TGF-ß3 was emphasised due to its twofold function of regulating the inflammatory environment and facilitating the regeneration of damaged tissues. Ischemic ulcer lesion healing is significantly influenced by TGF-ß3, which functions as an anti-inflammatory and pro-inflammatory mediator. Its correlation with ulcer characteristics and stages of healing suggests that it may have utility as a targeted therapeutic agent.

Chondrogenesis of mesenchymal stromal cells on the 3D printed polycaprolactone/fibrin/decellular cartilage matrix hybrid scaffolds in the presence of piascledine.

Nowadays, cartilage tissue engineering (CTE) is considered important due to lack of repair of cartilaginous lesions and the absence of appropriate methods for treatment. In this study, polycaprolactone (PCL) scaffolds were fabricated by three-dimensional (3D) printing and were then coated with fibrin (F) and acellular solubilized extracellular matrix (ECM). After extracting adipose-derived stem cells (ADSCs), 3D-printed scaffolds were characterized and compared to hydrogel groups. After inducing the chondrogenic differentiation in the presence of Piascledine and comparing it with TGF-ß3 for 28 days, the expression of genes involved in chondrogenesis (AGG, COLII) and the expression of the hypertrophic gene (COLX) were examined by real-time PCR. The expression of proteins COLII and COLX was also determined by immunohistochemistry. Glycosaminoglycan was measured by toluidine blue staining. 3D-printed scaffolds clearly improved cell proliferation, viability, water absorption and compressive strength compared to the hydrogel groups. Moreover, the use of compounds such as ECM and Piascledine in the process of ADSCs chondrogenesis induction increased cartilage-specific markers and decreased the hypertrophic marker compared to TGF-ß3. In Piascledine groups, the expression of COLL II protein, COLL II and Aggrecan genes, and the amount of glycosaminoglycan showed a significant increase in the PCL/F/ECM compared to the PCL and PCL/F groups.

An Advanced Bioconjugation Strategy for Covalent Tethering of TGFß3 with Silk Fibroin Matrices and its Implications in the Chondrogenesis Profile of Human BMSCs and Human Chondrocytes: A Paradigm Shift in Cartilage Tissue Engineering.

The transforming growth factor-ß class of cytokines plays a significant role in articular cartilage formation from mesenchymal condensation to chondrogenic differentiation. However, their exogenous addition to the chondrogenic media makes the protocol expensive. It reduces the bioavailability of the cytokine to the cells owing to their burst release. The present study demonstrates an advanced bioconjugation strategy to conjugate transforming growth factor-ß3 (TGFß3) with silk fibroin matrix covalently via a cyanuric chloride coupling reaction. The tethering and change in secondary conformation are confirmed using various spectroscopic analyses. To assess the functionality of the chemically modified silk matrix, human bone marrow-derived mesenchymal stem cells (hBMSCs) and chondrocytes are cultured for 28 days in a chondrogenic differentiation medium. Gene expression and histological analysis reveal enhanced expression of chondrogenic markers with intense Safranin-O and Alcian Blue staining in TGFß3 conjugated silk matrices than where TGFß3 is exogenously added to the media for both hBMSCs and chondrocytes. Therefore, this study successfully recapitulates the native niche of TGFß3 and the role of the silk as a growth factor stabilizer. When cultured over TGFß3 conjugated silk matrices, hBMSCs display increased proteoglycan secretion and maximum chondrogenic trait with attenuation of chondrocyte hypertrophy over human chondrocytes.

Heterogeneous response to TGF-ß1/3 isoforms in fibroblasts of different origins: implications for wound healing and tumorigenesis.

Identification of therapeutic targets for treating fibrotic diseases and cancer remains challenging. Our study aimed to investigate the effects of TGF-ß1 and TGF-ß3 on myofibroblast differentiation and extracellular matrix deposition in different types of fibroblasts, including normal/dermal, cancer-associated, and scar-derived fibroblasts. When comparing the phenotype and signaling pathways activation we observed extreme heterogeneity of studied markers across different fibroblast populations, even within those isolated from the same tissue. Specifically, the presence of myofibroblast and deposition of extracellular matrix were dependent on the origin of the fibroblasts and the type of treatment they received (TGF-ß1 vs. TGF-ß3). In parallel, we detected activation of canonical signaling (pSMAD2/3) across all studied fibroblasts, albeit to various extents. Treatment with TGF-ß1 and TGF-ß3 resulted in the activation of canonical and several non-canonical pathways, including AKT, ERK, and ROCK. Among studied cells, cancer-associated fibroblasts displayed the most heterogenic response to TGF-ß1/3 treatments. In general, TGF-ß1 demonstrated a more potent activation of signaling pathways compared to TGF-ß3, whereas TGF-ß3 exhibited rather an inhibitory effect in keloid- and hypertrophic scar-derived fibroblasts suggesting its clinical potential for scar treatment. In summary, our study has implications for comprehending the role of TGF-ß signaling in fibroblast biology, fibrotic diseases, and cancer. Future research should focus on unraveling the mechanisms beyond differential fibroblast responses to TGF-ß isomers considering inherent fibroblast heterogeneity.

TGF-ß3 Protects Neurons Against Intermittent Hypoxia-Induced Oxidative Stress and Apoptosis Through Activation of the Nrf-2/KEAP1/HO-1 Pathway via Binding to TGF-ßRI.

Intermittent hypoxia (IH) is the primary pathological manifestation of obstructive sleep apnea (OSA) and the main cause of OSA-induced cognitive impairment. Hippocampal neurons are considered to be critical cells affected by IH. Transforming growth factor-ß3 (TGF-ß3) is a cytokine with a neuroprotective effect, which plays a crucial role in resisting hypoxic brain injury, while its role in IH-induced neuronal injury is still unclear. Here, we aimed to clarify the mechanism of TGF-ß3 protecting IH-exposed neurons by regulating oxidative stress and secondary apoptosis. Morris water maze results revealed that IH exposure was unable to affect the vision and motor ability of rats, but significantly affected their spatial cognition. Second-generation sequencing (RNA-seq) and subsequent experiments supported that IH decreased TGF-ß3 expression and stimulated reactive oxygen species (ROS)-induced oxidative stress and apoptosis in rat hippocampus. In vitro, IH exposure significantly activated oxidative stress within HT-22 cells. Exogenous administration of Recombinant Human Transforming Growth Factor-ß3 (rhTGF-ß3) prevented ROS surge and secondary apoptosis in HT-22 cells caused by IH, while TGF-ß type receptor I (TGF-ßRI) inhibitor SB431542 blocked the neuroprotective effect of rhTGF-ß3. Nuclear factor erythroid 2-related factor 2 (Nrf-2) is a transcription factor preserving intracellular redox homeostasis. rhTGF-ß3 improved the nuclear translocation of Nrf-2 and activated downstream pathway. However, Nrf-2 inhibitor ML385 suppressed the activation of the Nrf-2 mechanism by rhTGF-3 and restored the effects of oxidative stress damage. These results indicate that TGF-ß3 binding to TGF-ßRI activates the intracellular Nrf-2/KEAP1/HO-1 pathway, reduces ROS creation, and attenuates oxidative stress and apoptosis in IH-exposed HT-22 cells.

Targeting Endogenous Reactive Oxygen Species Removal and Regulating Regenerative Microenvironment at Annulus Fibrosus Defects Promote Tissue Repair.

The excessive reactive oxygen species (ROS) level, inflammation, and weak tissue regeneration ability after annulus fibrosus (AF) injury constitute an unfavorable microenvironment for AF repair. AF integrity is crucial for preventing disc herniation after discectomy; however, there is no effective way to repair the AF. Herein, a composite hydrogel integrating properties of antioxidant, anti-inflammation, and recruitment of AF cells is developed through adding mesoporous silica nanoparticles modified by ceria and transforming growth factor ß3 (TGF-ß3) to the hydrogels. The nanoparticle loaded gelatin methacrylate/hyaluronic acid methacrylate composite hydrogels eliminate ROS and induce anti-inflammatory M2 type macrophage polarization. The released TGF-ß3 not only plays a role in recruiting AF cells but is also responsible for promoting extracellular matrix secretion. The composite hydrogels can be solidified in situ in the defect area to effectively repair AF in rats. The strategies targeting endogenous ROS removal and improving the regenerative microenvironment by the nanoparticle-loaded composite hydrogels have potential applications in AF repair and intervertebral disc herniation prevention.

A bio-polymeric scaffold incorporated with p-Coumaric acid enhances diabetic wound healing by modulating MMP-9 and TGF-ß3 expression.

Diabetic wounds lead to severe health complications as the tissue regeneration process fails predominantly due to prolonged inflammation, reactive oxygen species generation, and imbalance in collagen turnover. Modern wound dressings that can aid in wound management thus improving the public healthcare system, is the present need. This study aims to fabricate an effective wound dressing using plant polyphenol to treat chronic wounds as polyphenols possess excellent wound-healing ability. The collagen scaffold enriched with the polyphenol, p-Coumaric acid, was fabricated by freeze-drying method (Col-OxP3-Ca) and examined for its wound-healing ability by in vitro and in vivo analyses. Col-OxP3-Ca scaffold exhibited 85% antioxidant activity, biocompatibility in fibroblast cells, enhanced cell proliferation and migration rate. The diabetic excision wound treated with Col-OxP3-Ca scaffold healed within 21 days and a well-developed epidermis, blood vessels, hair follicle formation, fewer inflammatory cells and collagen deposition was observed in histological analysis. The immunohistochemical results depicted the enhanced expression of TGF-ß3 and lessened expression of the MMP-9 in Col-OxP3-Ca scaffold treatment group. p-Coumaric acid shortened the inflammatory stage, enhanced angiogenesis, tissue regeneration and balanced collagen turnover during healing. From this, we can accomplish that the Col-OxP3-Ca wound dressing could be an outstanding alternative to treat chronic wounds.

Influence of Transforming Growth Factors beta 1 and beta 3 in the Scar Formation Process.

BACKGROUND: Transforming growth factor-beta (TGF-ß) plays an instrumental role in forming scars and keloids. TGF-ß isoforms exhibit differential expression, indicating distinct wound healing and scar formation functions. However, the role of TGF-ß1 and TGF-ß3 in wound healing and scar formation remains unclear. This study aimed to compare the specific roles of TGF-ß1 and TGF-ß3 in wound healing and scar formation by biomolecular analysis. MATERIALS AND METHODS: The study was conducted by cell isolation and culture cells from a total of 20 human samples. Normal human fibroblasts (NHF) were isolated from normal human samples and myofibroblasts from the different scar types, namely hypertrophic (HT) and keloid (K) scars. NHF and cells from the HT, and K scar, each of which were divided into 3 sample groups: the untreated control, TGF-ß1 (10 µg/mL)-treated group, and TGF-ß3 (10 µg/mL)-treated group. The results of confocal microscopy and fluorescence-activated cell sorting experiments were compared. RESULTS: Both the HT and K groups had higher α-smooth muscle actin (α-SMA) expression than the NHF group in the untreated control group. In comparison with the untreated group, NHFs showed a significant increase in α-SMA expression in the TGF-ß1-treated group. HT showed a high α-SMA level, which was statistically significant compared with the normal fibroblasts. In the TGF-ß3-treated group, α-SMA expression was slightly increased in NHF as compared with the untreated group. TGF-ß3 treated HT exhibited a greater reduction in α-SMA expression than in the TGF-ß1 treated HT. K, on the other hand, had only a minimal effect on the treatment of TGF-ß1 and TGF-ß3. CONCLUSIONS: The findings suggest that TGF-ß3 may play a regulatory role in the wound repair process, which could be useful in the development of scar-reducing therapies for patients with scar-related cosmetic concerns.

Scaffolds containing GAG-mimetic cellulose sulfate promote TGF-ß 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-ß3) sequestration, as measured by rate of association, was higher for sulfated cellulose-containing scaffolds as compared to native GAGs. In addition, TGF-ß3 sequestration and retention over time was highest for NaCS-containing scaffolds. Sulfated cellulose-containing scaffolds loaded with TGF-ß3 showed enhanced chondrogenesis as indicated by a higher Collagen Type II:I ratio over native GAGs. NaCS-containing scaffolds loaded with TGF-ß3 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-ß3 mediated its effect through the Smad2/3 signaling pathway where the specificity of TGF-ß receptor (TGF- ßRI)-phosphorylated SMAD2/3 was verified with a receptor inhibitor. Therefore, studies demonstrate that scaffolds containing cellulose sulfate enhance TGF-ß3-induced MSC chondrogenic differentiation and show promise for promoting cartilage tissue regeneration.

Development of chondrocyte-laden alginate hydrogels with modulated microstructure and properties for cartilage regeneration.

Alginate hydrogel is an attractive biomaterial for cell microencapsulation. The microarchitecture of hydrogels can regulate cellular functions. This study aims to investigate the applicability of sodium citrate buffer (SCB) as a culture medium supplement for modulating the microstructure of alginate microbeads to provide a favorable microenvironment for chondrogenic induction. The chondrocyte-laden microbeads, with and without TGF-ß3 incorporation, were produced through an encapsulator. The obtained small-sized microbeads (~300 µm) were exposed to a treatment medium containing SCB, composed of varied concentrations of sodium citrate (1.10-1.57 mM), sodium chloride (3.00-4.29 mM), and ethylenediaminetetraacetic acid (0.60-0.86 mM) to partially degrade their crosslinked structure for 3 days, followed by culture in a normal medium until day 21. Scanning electron microscope micrographs demonstrated a loose hydrogel network with an enhanced pore size in the SCB-treated microbeads. Increasing the concentration of SCB in the treatment medium reduced the calcium content of the microbeads via a Na+ /Ca2+ exchange process and improved the water absorption of the microbeads, resulting in a higher swelling ratio. All the tested SCB concentrations were non-cytotoxic. Increases in aggrecan and type II collagen gene expression and their corresponding extracellular matrix accumulation, glycosaminoglycans, and type II collagen were vividly detected in the TGF-ß3-containing microbeads with increasing SCB concentrations in the treatment medium. Our findings highlighted that the combination of SCB treatment and TGF-ß3 incorporation in the chondrocyte-laden microbeads is a promising strategy for enhancing cartilage regeneration, which may contribute to a versatile application in cell delivery and tissue engineering.

Advanced 3D dynamic culture system with transforming growth factor-ß3 enhances production of potent extracellular vesicles with modified protein cargoes via upregulation of TGF-ß signaling.

INTRODUCTION: Mesenchymal stromal cells (MSCs) release extracellular vesicles (MSC-EVs) containing various cargoes. Although MSC-EVs show significant therapeutic effects, the low production of EVs in MSCs hinders MSC-EV-mediated therapeutic development. OBJECTIVES: Here, we developed an advanced three-dimensional (a3D) dynamic culture technique with exogenous transforming growth factor beta-3 (TGF-ß3) treatment (T-a3D) to produce potent MSC-EVs. METHODS: Our system enabled preparation of a highly concentrated EV-containing medium for efficient EV isolation and purification with higher yield and efficacy. RESULTS: MSC spheroids in T-a3D system (T-a3D spheroids) showed high expression of CD9 and TGF-ß3, which was dependent on TGF-ß signaling. Treatment with EVs produced under T-a3D conditions (T-a3D-EVs) led to significantly improved migration of dermal fibroblasts and wound closure in an excisional wound model. The relative total efficacy (relative yield of single-batch EVs (10-11-fold) × relative regeneration effect of EVs (2-3-fold)) of T-a3D-EVs was approximately up to 33-fold higher than that of 2D-EVs. Importantly the quantitative proteomic analyses of the T-a3D spheroids and T-a3D-EVs supported the improved EV production as well as the therapeutic potency of T-a3D-EVs. CONCLUSION: TGF-ß signalling differentially regulated by fluid shear stress produced in our system and exogenous TGF-ß3 addition was confirmed to play an important role in the enhanced production of EVs with modified protein cargoes. We suggest that the T-a3D system leads to the efficient production of MSC-EVs with high potential in therapies and clinical development.

Let-7a-3p Inhibits Chondrogenic Differentiation of Bone Marrow Mesenchymal Stem Cells by Targeting TGF-ß3.

OBJECTIVE: Chondrogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) plays an important role in osteoarthritis (OA) treatment. Studies have reported the association of transforming growth factor beta-3 (TGF-ß3) with chondrogenic differentiation of BMSCs. In this study, the upstream mechanism and functions of TGF-ß3 in chondrogenic differentiation of BMSCs were explored. METHODS AND RESULTS: Flow cytometry was performed for the positive and negative MSC markers. Chondrogenic differentiation of BMSCs was evaluated by Alcian blue staining. Gene expression and protein expression levels were measured by RT-qPCR and western blotting, respectively. Relationship between let-7a-3p and TGF-ß3 was confirmed using bioinformatics analysis, luciferase reporter and RNA pulldown assays. Subcellular distributions of TGF-ß3 and let-7a-3p were determined by FISH. In this study, BMSCs were identified to possess the characteristics of mesenchymal stem cells. TGF-ß3 was found to induce chondrogenic differentiation of BMSCs. Mechanically, TGF-ß3 was verified to be targeted by let-7a-3p. In rescue assays, let-7a-3p overexpression reversed the effects of TGF-ß3 overexpression on chondrogenic differentiation of BMSCs. CONCLUSION: Let-7a-3p inhibits chondrogenic differentiation of bone marrow mesenchymal stem cells by targeting TGF-ß3.

TGF-ß3 enhances cell-to-cell communication in chondrocytes via the ALK5/p-Smad3 axis.

Gap junctional intercellular communication (GJIC) is indispensable for the maintenance of physiological balance in articular cartilage. Transforming growth factor-ß3 (TGF-ß3), an important growth factor of TGF-ß superfamily, is well recognized to play a unique regulatory role in cartilage development and diseases. However, the role of TGF-ß3 in GJIC in adult chondrocytes remains elusive. This work aims to investigate the effect of TGF-ß3 on gap-junction mediated intercellular communication in chondrocytes. We first showed that TGF-ß3 could enhance the synaptic connections between chondrocytes by scanning electron microscopy (SEM) and promote the cell-to-cell communication in living chondrocytes by scrape loading/dye transfer assay. We then confirmed that TGF-ß3 enhanced cell-to-cell communication via up-regulation of connexin 43 (Cx43). We next found that TGF-ß3-enhanced GJIC required the participation of TGF-beta type I receptor ALK5 and depended on the activation of p-Smad3 signalling. Finally, through inhibitor experiments of SB525334 and SIS3, we demonstrated that TGF-ß3-induced functional GJIC in chondrocytes via the axis of ALK5/p-Smad3 signalling. Taking together, these results demonstrate a strong correlation between TGF-ß3 and GJIC in chondrocytes, which provides a new perspective on the importance of TGF-ß3 on cartilage physiology and pathobiology.

TGF-ß3 induces lactate production in Sertoli cell through inhibiting the Notch pathway.

BACKGROUNDS: In the testis, spermatocytes and spermatids rely on lactate produced by Sertoli cells (SCs) as energy source. Transforming growth factor-beta 3 (TGF-ß3) is one of the generally accepted paracrine regulatory factors of SC-created blood-testis barrier (BTB), yet its role in SC glycolysis and lactate production still remains unclear. OBJECTIVES: To investigate the effect of TGF-ß3 on glycolysis and lactate production in SCs and determine the role of lethal giant larvae 2 (Lgl2) and Notch signaling activity during this process. MATERIALS AND METHODS: Primary cultured rat SCs and TM4 cells were treated with different concentrations of TGF-ß3. In some experiments, cells were transfected with siRNA specifically targeting Lgl2 and then treated with TGF-ß3 or N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester. Lactate concentration, glucose and glutamine (Gln) consumption in the culture medium, activity of phosphofructokinase (PFK), lactate dehydrogenase (LDH), and glutaminase (Gls), ATP level, oxygen consumption, extracellular acidification, and mitochondrial respiration complex activity were detected using commercial kits. The protein level of Lgl2, LDH, monocarboxylate transporter 4 (MCT4), and activity of Akt, ERK, p38 MAPK, and Notch pathway were detected by Western blot. The stage-specific expression of Jagged1 was examined by immunohistochemistry (IHC) and qPCR after laser capture microdissection. Spermatogenesis in rat testis injected with recombinant Jagged1 (re-Jagged1) was observed by HE staining, and lactate concentration in testis lysate was measured at a different day point after re-Jagged1 treatment. RESULTS: Significant enhancement of lactate concentration was detected in a culture medium of both primary SCs and TM4 cells treated with TGF-ß3 at 3 or 5 ng/ml. Besides, other parameters of glycolysis, that is, glucose and Gln consumption, enzyme activity of PFK, LDH, and Gls displayed different levels of increment in primary SCs and TM4 cells after TGF-ß3 treatment. Mitochondria respiration of SCs was shown to decrease in response to TGF-ß3. Lgl2, MCT4, activity of ERK, and p38 MAPK were up-regulated, whereas Akt and Notch pathway activity were inhibited by TGF-ß3. Silencing of Lgl2 in SCs affected lactate production and attenuated the previous effects of TGF-ß3 on SC glycolysis except for Gln consumption, Gls activity, and activity of Akt, ERK, and p38. N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester (DAPT) treatment in SCs antagonized glycolysis suppression caused by Lgl2-silencing. In vivo analysis revealed a stage-specific expression of Jagged1 in contrary with TGF-ß3. Activating Notch signaling by re-Jagged1 resulted in restorable hypospermatogenesis and lowered lactate level in rat testis. CONCLUSION: TGF-ß3 induces lactate production in SC through up-regulating Lgl2, which weakened the Notch signaling activity and intensified glycolysis in SCs. Thus, besides the known function of TGF-ß3 as the BTB regulator, TGF-ß3-Lgl2-Notch may be considered an important pathway controlling SC glycolysis and spermatogenesis.

TGF-ß1 and -ß3 for Mesenchymal Stem Cells Chondrogenic Differentiation on Poly (Vinyl Alcohol)-Chitosan-Poly (Ethylene Glycol) Scaffold.

Transforming growth factor-beta 1 (TGF-ß1) has been reported to promote chondrogenic differentiation and proliferation in the multipotent stromal cell (MSCs), and the transforming growth factor-beta 3 (TGF-ß3) tends to be exclusively in promoting cell differentiation alone. The objective of this study was to determine the effect of TGF-ß1 and -ß3 on the MSCs chondrogenic differentiation on the poly (vinyl alcohol)-chitosan-poly (ethylene glycol) (PVA-NOCC-PEG) scaffold, compared with that of monolayer and pellet cultures. In this study, P2 rabbit bone marrow-derived MSCs were seeded either on the untreated six-well plate (for monolayer culture) or onto the PVA-NOCC-PEG scaffold or cultured as a pellet culture. The cultures were maintained in a chemically defined serum-free medium supplemented with 10 ng/mL of either TGF-ß1 or TGF-ß3. Cell viability assay, biochemical assay, and real-time polymerase chain reaction were performed to determine the net effect of cell proliferation and chondrogenic differentiation of each of the growth factors. The results showed that the PVA-NOCC-PEG scaffold enhanced MSCs cell proliferation from day 12 to 30 (p < 0.05); however, no significant differences were observed in the cell proliferation between the cultures supplemented with or without TGF-ß1 and TGF-ß3 (p > 0.05). In terms of chondrogenic differentiation, the PVA-NOCC-PEG scaffold augmented the GAGs secretion in MSCs and the mRNA expression levels of Sox9, Col2a1, Acan, and Comp were elevated (p < 0.05). However, there was no significant difference between both the TGF-ß1 and TGF-ß3-treated groups (p > 0.05). In conclusion, TGF-ß1 and TGF-ß3 enhanced the chondrogenic differentiation of MSCs seeded on the PVA-NOCC-PEG scaffold; however, there was no significant difference between the effect of TGF-ß1 and TGF-ß3. Impact statement Transforming growth factor-beta (TGF-ß) superfamily members is a key requirement for the in vitro chondrogenic differentiation of mesenchymal stem cells (MSCs). In this study, the effects of TGF-ß1 and -ß3 on MSC chondrogenic differentiation and proliferation on a novel three-dimensional scaffold, the poly(vinyl alcohol)-chitosan-poly(ethylene glycol) (PVA-NOCC-PEG) scaffold, was evaluated. In this study, the results showed both TGF-ß1 and TGF-ß3 can enhance the chondrogenic differentiation of MSCs seeded on the PVA-NOCC-PEG scaffold.

The effect of matrix stiffness on the chondrogenic differentiation of mesenchymal stem cells.

Articular cartilage is one of the most important weight-bearing components in human body, thus the chondrogenesis of stem cells is reactive to many intracellular and extracellular mechanical signals. As a unique physical cue, matrix stiffness plays an integral role in commitment of stem cell fate. However, when examining the downstream effects of matrix stiffness, most studies used different soluble factors to assist physical inducing process, which may mask the chondrogenic effects of matrix stiffness. Here we fabricated polyacrylamide (PAAm) hydrogels with gradient stiffness to unravel the role of matrix stiffness in chondrogenic process of mesenchymal stem cells (MSCs), with or without TGF-ß3 as induction factor. The results showed that with micromass culture mimicking relatively high cell density in vivo, the chondrogenic differentiation of MSCs can be promoted by soft substrates (about 0.5 kPa) independently with assembled cytoskeleton. Further analysis indicated that addition of TGF-ß3 generally increased expression level of cartilage-related markers and masked the stiffness-derived expression pattern of hypertrophic markers. These results demonstrate how mechanical cues experienced in developmental context regulate commitment of stem cell fate and have significant impact on the design of tissue regeneration materials.

Microenvironmentally optimized 3D-printed TGFß-functionalized scaffolds facilitate endogenous cartilage regeneration in sheep.

Clinically, microfracture is the most commonly applied surgical technique for cartilage defects. However, an increasing number of studies have shown that the clinical improvement remains questionable, and the reason remains unclear. Notably, recent discoveries revealed that signals from regenerated niches play a critical role in determining mesenchymal stem cell fate specification and differentiation. We speculate that a microenvironmentally optimized scaffold that directs mesenchymal stem cell fate will be a good therapeutic strategy for cartilage repair. Therefore, we first explored the deficiency of microfractures in cartilage repair. The microfracture not only induced inflammatory cell aggregation in blood clots but also consisted of loose granulation tissue with increased levels of proteins related to fibrogenesis. We then fabricated a functional cartilage scaffold using two strong bioactive cues, transforming growth factor-ß3 and decellularized cartilage extracellular matrix, to modulate the cell fate of mesenchymal stem cells. Additionally, poly(ε-caprolactone) was also coprinted with extracellular matrix-based bioinks to provide early mechanical support. The in vitro studies showed that microenvironmentally optimized scaffolds exert powerful effects on modulating the mesenchymal stem cell fate, such as promoting cell migration, proliferation and chondrogenesis. Importantly, this strategy achieved superior regeneration in sheep via scaffolds with biomechanics (restored well-organized collagen orientation) and antiapoptotic properties (cell death-related genes were also downregulated). In summary, this study provides evidence that microenvironmentally optimized scaffolds improve cartilage regeneration in situ by regulating the microenvironment and support further translation in human cartilage repair. STATEMENT OF SIGNIFICANCE: Although microfracture (MF)-based treatment for chondral defects has been commonly used, critical gaps exist in understanding the biochemistry of MF-induced repaired tissue. More importantly, the clinically unsatisfactory effects of MF treatment have prompted researchers to focus on tissue engineering scaffolds that may have sufficient therapeutic efficacy. In this manuscript, a 3D printing ink containing cartilage tissue-specific extracellular matrix (ECM), methacrylate gelatin (GelMA), and transforming growth factor-ß3 (TGF-ß3)-embedded polylactic-coglycolic acid (PLGA) microspheres was coprinted with poly(ε-caprolactone) (PCL) to fabricate tissue engineering scaffolds for chondral defect repair. The sustained release of TGF-ß3 from scaffolds successfully directed endogenous stem/progenitor cell migration and differentiation. This microenvironmentally optimized scaffold produced improved tissue repair outcomes in the sheep animal model, explicitly guiding more organized neotissue formation and therefore recapitulating the anisotropic structure of native articular cartilage. We hypothesized that the cell-free scaffolds might improve the clinical applicability and become a new therapeutic option for chondral defect repair.

A three-dimensional (3D), serum-free, Collagen Type I system for chondrogenesis of canine bone marrow-derived multipotent stromal cells (cMSCs).

The dog is an underrepresented large animal translational model for orthopedic cell-based tissue engineering. While chondrogenic differentiation of canine multipotent stromal cells (cMSCs) has been reported using the classic micromass technique, cMSCs respond inconsistently to this method. The objectives of this study were to develop a three-dimensional (3D), serum-free, Collagen Type I system to facilitate cMSC chondrogenesis and, once established, to determine the effect of chondrogenic growth factors on cMSC chondrogenesis. Canine MSCs were polymerized in 100 µL Collagen Type I gels (5 mg/mL) at 1 x 106 cells/construct. Constructs were assessed using morphometry, live/dead staining, and histology in 10 various chondrogenic media. Four media were selected for additional in-depth analyses via lactate dehydrogenase release, total glycosaminoglycan content, qPCR (COL1A1, COL2A, SOX9, ACAN, BGLAP and SP7), immunofluorescence, and TUNEL staining. In the presence of dexamethasone and transforming growth factor-ß3 (TGF-ß3), both bone morphogenic protein-2 (BMP-2) and basic fibroblast growth factor (bFGF) generated larger chondrogenic constructs, although BMP-2 was required to achieve histologic characteristics of chondrocytes. Chondrogenic medium containing dexamethasone, TGF-ß3, BMP-2 and bFGF led to a significant decrease in lactate dehydrogenase release at day 3 and glycosaminoglycan content was significantly increased in these constructs at day 3, 10, and 21. Both osteogenic and chondrogenic transcripts were induced in response to dexamethasone, TGF-ß3, BMP-2 and bFGF. Collagen Type II and X were detected in all groups via immunofluorescence. Finally, TUNEL staining was positive in constructs lacking BMP-2 or bFGF. In conclusion, the 3D, serum-free, Collagen Type-I assay described herein proved useful in assessing cMSC differentiation and will serve as a productive system to characterize cMSCs or to fabricate tissue engineering constructs for clinical use.

Controlled Release of TGF-ß3 for Effective Local Endogenous Repair in IDD Using Rat Model.

Introduction: Intervertebral disc (IVD) degeneration (IDD) is one of the most widespread musculoskeletal diseases worldwide and remains an intractable clinical challenge. Currently, regenerative strategies based on biomaterials and biological factors to facilitate IVD repair have been widely explored. However, the harsh microenvironment, such as increased ROS and acidity, of the degenerative region impedes the efficiency of IVD repair. Here, an intelligent biodegradable nanoplatform using hollow manganese dioxide (H-MnO2) was developed to modulate the degenerative microenvironment and release transforming growth factor beta-3 (TGF-ß3), which may achieve good long-term therapeutic effects on needle puncture-induced IDD. Methods: Surface morphology and elemental analysis of the MnO2 nanoparticles (NPs) were performed by transmission electron microscopy and an energy-dispersive X-ray spectroscopy detector system, respectively. The biological effects of MnO2 loaded with TGF-ß3 (TGF-ß3/MnO2) on nucleus pulposus cells (NPCs) were assessed via cytoskeleton staining, EdU staining, qPCR and immunofluorescence. The efficacy of TGF-ß3/MnO2 on needle puncture-induced IDD was further examined using MRI and histopathological and immunohistochemical staining. Results: The MnO2 NPs had a spherical morphology and hollow structure that dissociated in the setting of a low pH and H2O2 to release loaded TGF-ß3 molecules. In the oxidative stress environment, TGF-ß3/MnO2 was superior to TGF-ß3 and MnO2 NPs in the suppression of H2O2-induced matrix degradation, ROS, and apoptosis in NPCs. When injected into the IVDs of a rat IDD model, TGF-ß3/MnO2 was able to prevent the degeneration and promote self-regeneration. Conclusion: Use of an MnO2 nanoplatform for biological factors release to regulate the IDD microenvironment and promote endogenous repair may be an effective approach for treating IDD.