Foxk1 stimulates adipogenic differentiation via a peroxisome proliferator-activated receptor gamma 2-dependent mechanism.

Adipogenesis is a tightly regulated process, and its dysfunction has been linked to metabolic disorders such as obesity. Forkhead box k1 (Foxk1) is known to play a role in the differentiation of myogenic precursor cells and tumorigenesis of different types of cancers; however, it is not clear whether and how it influences adipocyte differentiation. Here, we found that Foxk1 was induced in mouse primary bone marrow stromal cells (BMSCs) and established mesenchymal progenitor/stromal cell lines C3H/10T1/2 and ST2 after adipogenic treatment. In addition, obese db/db mice have higher Foxk1 expression in inguinal white adipose tissue than nonobese db/m mice. Foxk1 overexpression promoted adipogenic differentiation of C3H/10T1/2, ST2 cells and BMSCs, along with the enhanced expression of CCAAT/enhancer binding protein-α, peroxisome proliferator-activated receptor γ (Pparγ), and fatty acid binding protein 4. Moreover, Foxk1 overexpression enhanced the expression levels of lipogenic factors during adipogenic differentiation in both C3H/10T1/2 cells and BMSCs. Conversely, Foxk1 silencing impaired these cells from fully differentiating. Furthermore, adipogenic stimulation induced the nuclear translocation of Foxk1, which depended on the mTOR and PI3-kinase signaling pathways. Subsequently, Foxk1 is directly bound to the Pparγ2 promoter, stimulating its transcriptional activity and promoting adipocyte differentiation. Collectively, our study provides the first evidence that Foxk1 promotes adipocyte differentiation from progenitor cells by promoting nuclear translocation and upregulating the transcriptional activity of the Pparγ2 promoter during adipogenic differentiation.

miR-196b-5p Regulates Osteoblast and Osteoclast Differentiation and Bone Homeostasis by Targeting SEMA3A.

miR-196b-5p plays a role in various malignancies. We have recently reported its function in regulating adipogenesis. However, it remains to be clarified whether and how miR-196b-5p affects bone cells and bone homeostasis. In this study, in vitro functional experiments showed an inhibitory effect of miR-196b-5p on osteoblast differentiation. Mechanistic explorations revealed that miR-196b-5p directly targeted semaphorin 3a (Sema3a) and inhibited Wnt/ß-catenin signaling. SEMA3A attenuated the impaired osteogenesis induced by miR-196b-5p. Osteoblast-specific miR-196b transgenic mice showed significant reduction of bone mass. Trabecular osteoblasts were reduced and bone formation was suppressed, whereas osteoclasts, marrow adipocytes, and serum levels of bone resorption markers were increased in the transgenic mice. The osteoblastic progenitor cells from the transgenic mice had decreased SEMA3A levels and exhibited retarded osteogenic differentiation, whereas those marrow osteoclastic progenitors exhibited enhanced osteoclastogenic differentiation. miR-196b-5p and SEMA3A oppositely regulated the expression of receptor activator of nuclear factor-κB ligand and osteoprotegerin. The calvarial osteoblastic cells expressing the transgene promoted osteoclastogenesis, whereas the osteoblasts overexpressing Sema3a inhibited it. Finally, in vivo transfection of miR-196b-5p inhibitor to the marrow reduced ovariectomy-induced bone loss in mice. Our study has identified that miR-196b-5p plays a key role in osteoblast and osteoclast differentiation and regulates bone homeostasis. Inhibition of miR-196b-5p may be beneficial for amelioration of osteoporosis. © 2023 American Society for Bone and Mineral Research (ASBMR).

Metastasis suppressor 1 interacts with protein tyrosine phosphatase receptor-δ to regulate adipogenesis.

Adipogenesis is a finely controlled process and its dysfunction may contribute to metabolic disorders such as obesity. Metastasis suppressor 1 (MTSS1) is a player in tumorigenesis and metastasis of various types of cancers. To date, it is not known whether and how MTSS1 plays a role in adipocyte differentiation. In the current study, we found that MTSS1 was upregulated during adipogenic differentiation of established mesenchymal cell lines and primary cultured bone marrow stromal cells. Gain-of-function and loss-of-function experiments uncovered that MTSS1 facilitated adipocyte differentiation from mesenchymal progenitor cells. Mechanistic explorations revealed that MTSS1 bound and interacted with FYN, a member of Src family of tyrosine kinases (SFKs), and protein tyrosine phosphatase receptor-δ (PTPRD). We demonstrated that PTPRD was capable of inducing the differentiation of adipocytes. Overexpression of PTPRD attenuated the impaired adipogenesis induced by the siRNA targeting MTSS1. Both MTSS1 and PTPRD activated SFKs by suppressing the phosphorylation of SFKs at Tyr530 and inducing the phosphorylation of FYN at Tyr419. Further investigation showed that MTSS1 and PTPRD were able to activate FYN. Collectively, our study has for the first time unraveled that MTSS1 plays a role in adipocyte differentiation in vitro through interacting with PTPRD and thereby activating SFKs such as FYN tyrosine kinase.

Chordin Like-1 Regulates Osteoblast and Adipocyte Differentiation Through Stabilizing Insulin-Like Growth Factor Binding Protein 3.

Chordin like-1 (CHRDL1) is an antagonist of bone morphogenetic proteins (BMPs) that acts through binding BMPs and blocking their interaction with BMP receptors. CHRDL1 plays a role in osteoblast differentiation but controversial effects were reported. On the other hand, the role of CHRDL1 in adipogenesis is unknown. In the present study, we investigated the function of CHRDL1 in regulating differentiation of osteoblasts and adipocytes and elucidated the underlying mechanism. CHRDL1 expression was downregulated during osteogenesis while it was upregulated during adipogenesis in primary cultured and established mesenchymal progenitor cell lines. Functional experiments revealed that CHRDL1 suppressed osteoblast differentiation and promoted adipocyte differentiation. Mechanistic explorations revealed that CHRDL1 is directly bound to insulin-like growth factor binding protein 3 (IGFBP3) and attenuated the degradation of the latter. Furthermore, CHRDL1 and IGFBP3 suppressed the activity of insulin receptor substrate 1 (IRS1)/AKT serine/threonine kinase (AKT)/mechanistic target of rapamycin kinase complex 1 (mTORC1) signaling in progenitor cells undergoing osteogenic differentiation. By contrast, they activated AKT/mTORC1 signaling independently of IRS1 during adipogenic differentiation. CHRDL1 enhanced the interaction of nuclear IGFBP3 and retinoid X receptor α (RXRα) during adipogenesis, and inhibition of RXR inactivated AKT and attenuated the stimulation of adipogenic differentiation by CHRDL1. Overexpression of IGFBP3 relieved the perturbation of osteogenic and adipogenic differentiation of progenitor cells induced by CHRDL1 silencing. Finally, CHRDL1 and IGFBP3 were upregulated in the trabecular bone of aged mice. Our study provides evidence that CHRDL1 reciprocally regulates osteoblast and adipocyte differentiation through stabilizing IGFBP3 and differentially modulating AKT/mTORC1 signaling.

Metastasis suppressor 1 controls osteoblast differentiation and bone homeostasis through regulating Src-Wnt/ß-catenin signaling.

Metastasis suppressor 1 (MTSS1) plays an inhibitory role in tumorigenesis and metastasis of a variety of cancers. To date, the function of MTSS1 in the differentiation of marrow stromal progenitor cells remains to be explored. In the current study, we investigated whether and how MTSS1 has a role in osteoblast differentiation and bone homeostasis. Our data showed that MTSS1 mRNA was upregulated during osteoblast differentiation and downregulated in the osteoblastic lineage cells of ovariectomized and aged mice. Functional studies revealed that MTSS1 promoted the osteogenic differentiation from marrow stromal progenitor cells. Mechanistic explorations uncovered that the inactivation of Src and afterward activation of canonical Wnt signaling were involved in osteoblast differentiation induced by MTSS1. The enhanced osteogenic differentiation induced by MTSS1 overexpression was attenuated when Src was simultaneously overexpressed, and conversely, the inhibition of osteogenic differentiation by MTSS1 siRNA was rescued when the Src inhibitor was supplemented to the culture. Finally, the in vivo transfection of MTSS1 siRNA to the marrow of mice significantly reduced the trabecular bone mass, along with the reduction of trabecular osteoblasts, the accumulation of marrow adipocytes, and the increase of phospho-Src-positive cells on the trabeculae. No change in the number of osteoclasts was observed. This study has unraveled that MTSS1 contributes to osteoblast differentiation and bone homeostasis through regulating Src-Wnt/ß-catenin signaling. It also suggests the potential of MTSS1 as a new target for the treatment of osteoporosis.

A novel Sprouty4-ERK1/2-Wnt/ß-catenin regulatory loop in marrow stromal progenitor cells controls osteogenic and adipogenic differentiation.

BACKGROUND: Sprouty (SPRY) proteins play critical roles in controlling cell proliferation, differentiation, and survival by inhibiting receptor tyrosine kinase (RTK)-mediated extracellular signal-regulated kinase (ERK) signaling. Recent studies have demonstrated that SPRY4 negatively regulates angiogenesis and tumor growth. However, whether SPRY4 regulates osteogenic and/or adipogenic differentiation of mesenchymal stem cells remains to be explored. RESULTS: In this study, we investigated the expression pattern of Spry4 and found that its expression was regulated during the differentiation of mouse marrow stromal progenitor cells and increased in the metaphysis of ovariectomized mice. In vitro loss-of-function and gain-of-function studies demonstrated that SPRY4 inhibited osteogenic differentiation and stimulated adipogenic differentiation of progenitor cells. In vivo experiments showed that silencing of Spry4 in the marrow of C57BL/6 mice blocked fat accumulation and promoted osteoblast differentiation in ovariectomized mice. Mechanistic investigations revealed the inhibitory effect of SPRY4 on canonical wingless-type MMTV integration site (Wnt) signaling and ERK pathway. ERK1/2 was shown to interact with low-density lipoprotein receptor-related protein 6 (LRP6) and activate the canonical Wnt signaling pathway. Inactivation of Wnt signaling attenuated the inhibition of adipogenic differentiation and stimulation of osteogenic differentiation by Spry4 small interfering RNA (siRNA). Finally, promoter study revealed that ß-catenin transcriptionally inhibited the expression of Spry4. CONCLUSIONS: Our study for the first time suggests that a novel SPRY4-ERK1/2-Wnt/ß-catenin regulatory loop exists in marrow stromal progenitor cells and plays a key role in cell fate determination. It also highlights the potential of SPRY4 as a novel therapeutic target for the treatment of metabolic bone disorders such as osteoporosis.

A novel long noncoding RNA PGC1ß-OT1 regulates adipocyte and osteoblast differentiation through antagonizing miR-148a-3p.

Long noncoding RNAs (LncRNAs) have been implicated in the regulation of adipocyte and osteoblast differentiation. However, the functional contributions of LncRNAs to adipocyte or osteoblast differentiation remain largely unexplored. In the current study we have identified a novel LncRNA named peroxisome proliferator-activated receptor γ coactivator-1ß-OT1 (PGC1ß-OT1). The expression levels of PGC1ß-OT1 were altered during adipogenic and osteogenic differentiation from progenitor cells. 5'- and 3'-rapid amplification of cDNA ends (RACE) revealed that PGC1ß-OT1 is 1759 nt in full length. Overexpression of PGC1ß-OT1 in progenitor cells inhibited adipogenic differentiation, whereas silencing of endogenous PGC1ß-OT1 induced adipogenic differentiation. By contrast, overexpression of PGC1ß-OT1 in progenitor cells stimulated, whereas silencing of PGC1ß-OT1 inhibited osteogenic differentiation. In vivo experiment showed that silencing of endogenous PGC1ß-OT1 in marrow stimulated fat accumulation and decreased osteoblast differentiation in mice. Mechanism investigations revealed that PGC1ß-OT1 contains a functional miR-148a-3p binding site. Overexpression of the mutant PGC1ß-OT1 with mutation at the binding site failed to regulate either adipogenic or osteogenic differentiation. In vivo crosslinking combined with affinity purification studies demonstrated that PGC1ß-OT1 physically associated with miR-148a-3p through the functional miR-148a-3p binding site. Furthermore, PGC1ß-OT1 affected the expression of endogenous miR-148a-3p and its target gene lysine-specific demethylase 6b (KDM6B). Supplementation of miR-148a-3p in progenitor cells blocked the inhibitory effect of PGC1ß-OT1 on adipocyte formation. Moreover, overexpression of Kdm6b restored the osteoblast differentiation which was inhibited by silencing of endogenous PGC1ß-OT. Our studies provide evidences that the novel LncRNA PGC1ß-OT1 reciprocally regulates adipogenic and osteogenic differentiation through antagonizing miR-148a-3p and enhancing KDM6B effect.

Fasciocutaneous flap with perforating branches of peroneal artery repairing soft tissue loss in anterior and middle parts of children's feet: A STROBE-compliant article.

Repairing soft tissue loss in feet's anterior and middle parts has become a problem, especially for children. We observed the feasibility and clinical effects of superficial peroneal fasciocutaneous flap pedicled with terminal perforating branches of peroneal artery for repairing children's feet.Between January 2015 and December 2016, soft tissue loss in anterior and middle regions of feet were repaired using superficial peroneal fasciocutaneous flap pedicled with terminal perforating branches of peroneal artery in 8 children with a median age of 6.5 [4-9, interquartile range (IQR) = 3] years. The skin of lower leg was intact, and the soft tissue loss area was located in the anterior and middle regions of feet with a size of 5 cm × 4 cm to 11 cm × 7 cm combined with the exposure of tendons and joints in all the 8 children. On the basis of the conditions above, there were no indications of free skin grafting. Foot wounds were repaired all with the superficial peroneal fasciocutaneous flap pedicled with terminal perforating branches of peroneal artery (6 cm × 5 cm to 12 cm × 8 cm), and then the donor area was sutured to narrow the donor area followed by intermediate split thickness skin graft. The perforating branch trunk of peroneal artery was used as a rotation point (4 cm above the lateral malleolus) in 5 children and descending branch of perforating branch of peroneal artery as a rotation point (2 cm under the lateral malleolus) in 3 children.All flaps survived with primary healing in the 8 children. Postoperative median 7.5-month (3-12, IQR = 4.5) follow-up indicated that flap color and texture were fine, the appearances of donor and recipient areas were satisfactory, wearing shoes was not affected, and walking function and foot blood circulation were normal.For intractable soft tissue loss in the anterior and middle regions of children's feet, superficial peroneal fasciocutaneous flap pedicled with terminal perforating branches of peroneal artery can improve recipient area appearance and walking function because it has the characteristics of reliable blood supply and convenient rotation. It is worth using this method widely in clinics.

miR-337 can be a key negative regulator in melanoma.

Incidence of melanoma is increasing annually worldwide. There remains a lack of suitable treatment methods which can significantly improve the 5-year survival rates of patients. It is established that micro RNAs (miRNAs) have important roles in the diagnosis and treatment of cancer. MiR-337 had been reported to regulate the development of variety of cancers, as a cancer suppressive factor. In our research we found that miR-337 had a lower expression in melanoma than adjacent tissues. The patients who had a lower miR-337 also got a worse survival. MiR-337 could target STAT3 to regulate the occurrence and development of melanoma.  In summary, our findings suggest that the miR-337/STAT3 axis may serve as a potential target for the treatment of melanoma.

Identification and function analysis of contrary genes in Dupuytren's contracture.

The present study aimed to analyze the expression of genes involved in Dupuytren's contracture (DC), using bioinformatic methods. The profile of GSE21221 was downloaded from the gene expression ominibus, which included six samples, derived from fibroblasts and six healthy control samples, derived from carpal-tunnel fibroblasts. A Distributed Intrusion Detection System was used in order to identify differentially expressed genes. The term contrary genes is proposed. Contrary genes were the genes that exhibited opposite expression patterns in the positive and negative groups, and likely exhibited opposite functions. These were identified using Coexpress software. Gene ontology (GO) function analysis was conducted for the contrary genes. A network of GO terms was constructed using the reduce and visualize gene ontology database. Significantly expressed genes (801) and contrary genes (98) were screened. A significant association was observed between Chitinase-3-like protein 1 and ten genes in the positive gene set. Positive regulation of transcription and the activation of nuclear factor-κB (NF-κB)-inducing kinase activity exhibited the highest degree values in the network of GO terms. In the present study, the expression of genes involved in the development of DC was analyzed, and the concept of contrary genes proposed. The genes identified in the present study are involved in the positive regulation of transcription and activation of NF-κB-inducing kinase activity. The contrary genes and GO terms identified in the present study may potentially be used for DC diagnosis and treatment.

Venous arterialization for the treatment of large-area foot skin retrograde avulsion.

Between 2009 and 2011, three patients with large-area foot skin retrograde avulsion (more than 1% of the body surface area) underwent venous arterialization. Anastomosis of the artery in the wound surface with the vein in the skin flap and an appropriate number of venous end-to-end anastomoses were performed. The skin flaps survived in all 3 patients. Six months postoperatively, the flap elasticity and appearance were close to that of normal skin, and foot function was better without scar contracture. When venous arterialization is used to treat foot avulsion, the following points should be noted. Surgical indications include no fresh bleeding from the wound edge of the avulsed skin after debridement, more complete avulsed skin, and superficial veins that do not completely separate from the avulsed skin. Venous arterialization is not suitable to avulsion with fresh bleeding, avulsed skin in small fragments, and avulsion with a subcutaneous venous network embolism. During debridement, the subcutaneous venous network should be protected to avoid exposing the vein stems outside the fat layer. If the avulsion is less than 1% of the body surface area, arterial-venous anastomosis can provide adequate blood supply. Venous-venous anastomosis is performed as much as possible to enhance venous return and decrease microcirculatory pressure, which is conducive to the establishment of effective blood circulation.

The effect of knee position on blood loss and range of motion following total knee arthroplasty.

PURPOSE: This study prospectively assessed the effects of knee position on blood loss and range of motion after primary total knee arthroplasty (TKA). METHODS: One hundred and ten consecutive TKA patients were randomized into flexion group and extension group. Both groups had the leg elevated 30° at the hip over an inactive CPM for 72 h postoperatively. The flexion group had the knee flexed to 30° during this period. The extension group had the knee extended fully. Perioperative blood loss, hidden blood loss, knee swelling, ecchymosis, analgesia requirements, range of motion (ROM), fixed flexion deformity (FFD), straight-leg raising action, and postoperative complications within 6 weeks of surgery were measured for evaluation and comparison. RESULTS: The postoperative hidden blood loss, knee swelling, and scope of ecchymosis were significantly lower in the flexion group than in the extension group, and ROM and straight-leg raising action were significantly higher during the early period after operation. No significant difference was observed in perioperative blood loss, the amount of morphine used, or FFD in the early postoperative period or in ROM and FFD at 6 weeks postoperatively. CONCLUSIONS: The findings of this study indicate that flexion of the knee to 30° with the leg elevated 30° at the hip after total knee arthroplasty may mitigate knee swelling and provide other beneficial results during the early rehabilitation following TKA. LEVEL OF EVIDENCE: Prospective comparative study, Level I.

Treatment of severe hand deformities caused by epidermolysis bullosa.

Little research has been done regarding the treatment of severe hand deformities caused by epidermolysis bullosa. A 14-year-old boy was diagnosed with congenital epidermolysis bullosa. He was treated in our hospital several times, but the pathogenetic condition worsened. On examination, both hands were clenched fists and had scar formation. Skin fusion was observed between the 5 fingers. Nails were absent and the thumb was in the fist. His fingers were short, and active and passive flexion and extension could not be performed. The right hand was treated first. After the adhesions were separated, we found that the 5 fingers were connected by dermis. After the dermis was separated and the hand was fixed in the extension position, there were small cutaneous deficiencies. The fingers were fixed in the functional position with Kirschner wires. The wound surface was covered with self-made aureomycin ointment gauze. After regular dressing changes for 6 weeks, the wound surface was completely healed. After 3 months of rehabilitation training, most hand function was recovered.Based on our findings in this case, when treating patients with epidermolysis bullosa, physicians must carefully observe whether enough dermis exists to avoid an unnecessary skin graft. We also found that the quality of skin used in skingrafting is questionable due to pathological changes in the skin. If there is enough dermis and the cutaneous deficiency is smaller after contracture release, the covering of drug dressings on the cutaneous deficiency is more conducive to the recovery of limb function and the reduction of damage to the donor sites.

Plastic repair for a case with synpolydactyly.

On March 23, 2010, we successfully treated a boy with synpolydactyly who had a total of 31 fingers and toes. Although there was bone syndactyly both the hands of the boy, one-step correction of four extremities was successful, this operation lasted 5 h and 20 min and intraoperative bleeding was about 50 ml. Skin grafting was successful after operation and all incisions healed well. The appearance and function of hands and feet were satisfactory.

[Experimental study on losartan decreasing denervated skeletal muscle atrophy through reducing cell apoptosis].

OBJECTIVE: To explore the role of cell apoptosis in denervated skeletal muscle atrophy in rats and the effect of losartan on it. METHODS: Forty-two Sprague Dawley rats were randomly divided into 3 groups: group I (n = 14, normal control group), group II (n = 14, denervated group) and group III (n = 14, losartan group). The rats were not treated in group I, and were made denervated gastrocnemius models in groups II and III. In group III, the rats were treated with losartan 10 mg/kg x d by gavage and with normal saline in groups I and II. After 4 weeks, gastrocnemius mass to body mass ratio (GAS/BM) served as the degree of muscle atrophy. Apoptotic cells in gastrocnemius were stained in situ by using TUNEL. Gastrocnemius Bcl-2 and Bax protein were quantified by immunohistochemistry and Western blot. Bax/Bcl-2 served as the degree of apoptosis. RESULTS: The ratio of apoptosis was higher in group II than that in group I (11.32% +/- 4.51% vs 0.56% +/- 0.21%, P < 0.05). The ratio of apoptosis was lower in group III than that in group II (7.21% +/- 2.05% vs 11.32% +/- 4.51%, P < 0.05). The atrophy of skeletal muscle (GAS/BM) in group II was more serious than that in group I (11.68 +/- 1.98 vs 12.86 +/- 0.74, P < 0.05), there was no significant difference between group III and group II (12.11 +/- 0.65 vs 11.68 +/- 1.98, P > 0.05). The expression of Bcl-2 in group II (18.3% +/- 4.9%) was significantly lower than that in group I (27.5% +/- 2.8%) and group III (25.5% +/- 3.5%); there was no significant difference between group III and group I (P > 0.05). The expression of Bax in group II (24.1% +/- 3.1%) was significantly higher than that in group I (22.1% +/- 3.6%) and group III (21.7% +/- 2.3%); there was no significant difference between group III and group I (P > 0.05). Western blot results showed that: the expressions of Bcl-2 were 122.5 +/- 14.6 in group II, 135.3 +/- 6.2 in group I and 139.2 +/- 16.2 in group III; showing significant differences between group II and group I, between group III and group II (P < 0.05). The expressions of Bax were 107.1 +/- 15.8 in group II, 89.3 +/- 8.4 in group I, and 94.2 +/- 9.5 in group III; showing significant differences between group II and group I, between group III and group II (P < 0.05). There was no significant difference in the expression of Bcl-2 and Bax between group III and group I (P > 0.05). CONCLUSION: Cell apoptosis plays an important role in denervated skeletal muscle atrophy in rats and may be one of the factors causing skeletal muscle atrophy. Losartan can decrease skeletal muscle cell apoptosis through regulating the ratio of Bax/Bcl-2.

Replantation of completely amputated thumbs with venous arterialization.

PURPOSE: To report a new method of replanting completely amputated thumbs with venous arterialization. METHODS: In 6 replantation surgeries of completely amputated thumbs performed during the period 1999-2003, the proximal artery was anastomosed with a vein of the amputated part to establish inflow and the proximal vein was anastomosed with several other veins in the amputated part to establish outflow. This was because the proper palmar digital arteries were seriously injured or anastomosis of proper palmar digital arteries failed many times. RESULTS: All the replanted thumbs survived, regained good sensory and motor functions, and showed no difference from thumbs replanted conventionally. CONCLUSIONS: Venous arterialization may salvage otherwise unreplantable thumbs.