Yajie Lv

TNF-α Inhibits FoxO1 by Upregulating miR-705 to Aggravate Oxidative Damage in Bone Marrow-Derived Mesenchymal Stem Cells during Osteoporosis

Decline of antioxidant defense after estrogen deficiency leads to oxidative damage in bone marrow‐derived mesenchymal stem cells (BMMSCs), resulting a defect of bone formation in osteoporosis. Forkhead box O1 (FoxO1) protein is crucial for defending physiological oxidative damage in bone. But whether FoxO1 is involved in the oxidative damage during osteoporosis is largely unknown. In this study, we found that FoxO1 protein accumulation was decreased in BMMSCs of ovariectomized mice. The decrease of FoxO1 resulted in the suppression of manganese superoxide dismutase (Sod2) and catalase (Cat) expression and accumulation of reactive oxygen species (ROS), inhibiting the osteogenic differentiation of BMMSCs. The decline of FoxO1 protein was caused by tumor necrosis factor‐alpha (TNF‐α) accumulated after estrogen deficiency. Mechanistically, TNF‐α activated NF‐κB pathway to promote microRNA‐705 expression, which function as a repressor of FoxO1 through post‐transcriptional regulation. Inhibition of NF‐κB pathway or knockdown of miR‐705 largely prevented the decline of FoxO1‐mediated antioxidant defense caused by TNF‐α and ameliorated the oxidative damage in osteoporotic BMMSCs. Moreover, the accumulated ROS further activated NF‐κB pathway with TNF‐α, which formed a feed‐forward loop to persistently inhibiting FoxO1 protein accumulation in BMMSCs. In conclusion, our study revealed that the decline of FoxO1 is an important etiology factor of osteoporosis and unclosed a novel mechanism of FoxO1 regulation by TNF‐α. These findings suggested a close correlation between inflammation and oxidative stress in stem cell dysfunction during degenerative bone diseases. Stem Cells 2016;34:1054–1067

Use of anti-tumor necrosis factor agents: A possible therapy for vitiligo

Vitiligo is a depigmenting skin disorder resulting from the loss of melanocytes in the epidermis. Although the exact aetiology of vitiligo has not yet been established, the abnormal immune responses have been frequently observed in vitiligo patients. Moreover, some vitiligo patients show higher lesion levels of tumor necrosis factor (TNF)-alpha. TNF-alpha is an important pleiotropic cytokine that exerts potent pro-inflammatory effects. There is growing evidence that TNF-alpha plays an important role in the pathomechanism process of some autoimmunity diseases, including ankylosing spondylitis (AS). Treated with anti-TNF agents infliximab, with the improvement of AS, a patients vitiligo lesions also faded out. Therefore, we hypothesized that TNF-alpha play an important role in vitiligo. On the one hand, TNF-alpha destroys melanocytes through induction of various apoptotic pathways. On the other hand, TNF-alpha inhibits melanocyte stem cells differentiation. Anti-TNF therapy may be an effective treatment for vitiligo.

Anti‐aging pharmacology in cutaneous wound healing: effects of metformin, resveratrol, and rapamycin by local application

Cutaneous wounds are among the most common soft tissue injuries and are particularly hard to heal in aging. Caloric restriction (CR) is well documented to extend longevity; pharmacologically, profound rejuvenative effects of CR mimetics have been uncovered, especially metformin (MET), resveratrol (RSV), and rapamycin (RAPA). However, locally applied impacts and functional differences of these agents on wound healing remain to be established. Here, we discovered that chronic topical administration of MET and RSV, but not RAPA, accelerated wound healing with improved epidermis, hair follicles, and collagen deposition in young rodents, and MET exerted more profound effects. Furthermore, locally applied MET and RSV improved vascularization of the wound beds, which were attributed to stimulation of adenosine monophosphate‐activated protein kinase (AMPK) pathway, the key mediator of wound healing. Notably, in aged skin, AMPK pathway was inhibited, correlated with impaired vasculature and reduced healing ability. As therapeutic approaches, local treatments of MET and RSV prevented age‐related AMPK suppression and angiogenic inhibition in wound beds. Moreover, in aged rats, rejuvenative effects of topically applied MET and RSV on cell viability of wound beds were confirmed, of which MET showed more prominent anti‐aging effects. We further verified that only MET promoted wound healing and cutaneous integrity in aged skin. These findings clarified differential effects of CR‐based anti‐aging pharmacology in wound healing, identified critical angiogenic and rejuvenative mechanisms through AMPK pathway in both young and aged skin, and unraveled chronic local application of MET as the optimal and promising regenerative agent in treating cutaneous wound defects.

Giant primary cutaneous spindle cell B-cell lymphoma of follicle center cell origin.

Spindle cell B-cell lymphoma is a rare morphologic variant of B-cell lymphoma that is generally associated with follicle center cell origin. It is typically found on the skin and presents as single nodule or plaque with a diameter of several centimeters. It is also characterized by abnormal spindle cells with elongated or spindle-shaped nuclei, and usually stained positive for Bcl-6 and negative for multiple myeloma oncogene 1 (MUM-1). In this report, we describe a giant primary cutaneous spindle cell B-cell lymphoma measured 20 cm × 25 cm, substantially larger than all the previously reported cases. Histologic examination revealed that the neoplasm was mainly located in the dermis and subcutaneous fat, and had infiltrated into striated muscles of the patients back. The neoplasm cells contained elongated or spindle-shaped nuclei. Immunohistochemistry results demonstrated that the neoplasm cells were stained positive for CD20, CD79, and Bcl-6, negative for Bcl-2 and MUM-1, and focally positive for CD5, CD10, CD31, and CD43. These results collectively indicated that the neoplasm was of follicle center cell origin. The neoplasm was excised and the patient was still alive without systemic involvement after 4 years of follow-up.

Mutual enhancement between heparanase and vascular endothelial growth factor: a novel mechanism for melanoma progression.

Heparanase is closely related to growth factors in the role of promoting tumor progression. Among them, vascular endothelial growth factor (VEGF) is necessary for tumor vascularity and metastasis. Release of VEGF by heparanase can initiate relative signaling pathways, resulting in an up-regulation of transcriptional factors related with heparanase. Therefore, VEGF likely has a potential function as a regulator of heparanase expression in melanoma. We hypothesized that a novel mechanism exists where heparanase and VEGF are mutually enhanced in melanoma. Our study was conducted to validate the hypothetical mutual enhancement and elucidate its effect on melanoma progression. We found that the addition of exogenous VEGF and its cDNA transfection induce heparanase over-expression by means of western-blot and real-time RT-PCR, while anti-VEGF siRNA reduces heparanase expression in A2058 and WM793 melanoma cell lines. Likewise, VEGF expression is also regulated by heparanase in these two cell lines. Additionally, the cells with mutual enhancement phenotypes exhibit higher proliferation and transmigration capacity. PD98059, a specific inhibitor of the MEK/ERK signaling pathway, is involved in this mutual enhancement. These data are the first to show that heparanase and VEGF have a mutual enhancement in melanoma cells, which may be a novel mechanism for promoting melanoma progression.

Meta-analysis shows strong positive association of the TNF-α gene with tumor stage in bladder cancer.

There is no consensus on the association between the tumor necrosis factor-α (TNF-α) gene promoter –308 A/G single nucleotide polymorphisms and bladder cancer risk. To obtain a more precise estimation of this correlation, we conducted a meta-analysis. The PubMed, MEDLINE, Cochrane Library and China National Knowledge Infrastructure (CNKI) databases were searched for relevant published studies. Seven case-control studies with a total of 1,311 cases and 1,436 controls were identified and analyzed. A notable correlation was observed between the TNF-α genotype and bladder cancer grade (AA+GA vs. GG; odds ratio 1.96, 95% confidence interval 1.37–2.80, p = 0.0002). In summary, this meta-analysis demonstrates that the TNF-α –308 AA+GA genotype may be a marker to the tumor-invasive stage of bladder cancer.

Resveratrol counteracts bone loss via mitofilin-mediated osteogenic improvement of mesenchymal stem cells in senescence-accelerated mice

Rational: Senescence of mesenchymal stem cells (MSCs) and the related functional decline of osteogenesis have emerged as the critical pathogenesis of osteoporosis in aging. Resveratrol (RESV), a small molecular compound that safely mimics the effects of dietary restriction, has been well documented to extend lifespan in lower organisms and improve health in aging rodents. However, whether RESV promotes function of senescent stem cells in alleviating age-related phenotypes remains largely unknown. Here, we intend to investigate whether RESV counteracts senescence-associated bone loss via osteogenic improvement of MSCs and the underlying mechanism. Methods: MSCs derived from bone marrow (BMMSCs) and the bone-specific, senescence-accelerated, osteoblastogenesis/osteogenesis-defective mice (the SAMP6 strain) were used as experimental models. In vivo application of RESV was performed at 100 mg/kg intraperitoneally once every other day for 2 months, and in vitro application of RESV was performed at 10 μM. Bone mass, bone formation rates and osteogenic differentiation of BMMSCs were primarily evaluated. Metabolic statuses of BMMSCs and the mitochondrial activity, transcription and morphology were also examined. Mitofilin expression was assessed at both mRNA and protein levels, and short hairpin RNA (shRNA)-based gene knockdown was applied for mechanistic experiments. Results: Chronic intermittent application of RESV enhances bone formation and counteracts accelerated bone loss, with RESV improving osteogenic differentiation of senescent BMMSCs. Furthermore, in rescuing osteogenic decline under BMMSC senescence, RESV restores cellular metabolism through mitochondrial functional recovery via facilitating mitochondrial autonomous gene transcription. Molecularly, in alleviating senescence-associated mitochondrial disorders of BMMSCs, particularly the mitochondrial morphological alterations, RESV upregulates Mitofilin, also known as inner membrane protein of mitochondria (Immt) or Mic60, which is the core component of the mitochondrial contact site and cristae organizing system (MICOS). Moreover, Mitofilin is revealed to be indispensable for mitochondrial homeostasis and osteogenesis of BMMSCs, and that insufficiency of Mitofilin leads to BMMSC senescence and bone loss. More importantly, Mitofilin mediates resveratrol-induced mitochondrial and osteogenic improvements of BMMSCs in senescence. Conclusion: Our findings uncover osteogenic functional improvements of senescent MSCs as critical impacts in anti-osteoporotic practice of RESV, and unravel Mitofilin as a novel mechanism mediating RESV promotion on mitochondrial function in stem cell senescence.

Nestin Positive Bone Marrow Derived Cells Responded to Injury Mobilize into Peripheral Circulation and Participate in Skin Defect Healing

Exogenously infused mesenchymal stem cells (MSCs) are thought to migrate to injury site through peripheral blood stream and participate in tissue repair. However, whether and how endogenous bone marrow MSCs mobilized to circulating and targeted to tissue injury has raised some controversy, and related studies were restricted by the difficulty of MSCs identifying in vivo. Nestin, a kind of intermediate filament protein initially identified in neuroepithelial stem cells, was recently reported as a credible criteria for MSCs in bone marrow. In this study, we used a green fluorescent protein (GFP) labeled bone marrow replacement model to trace the nestin positive bone marrow derived cells (BMDCs) of skin defected-mice. We found that after skin injured, numbers of nestin+ cells in peripheral blood and bone marrow both increased. A remarkable concentration of nestin+ BMDCs around skin wound was detected, while few of these cells could be observed in uninjured skin or other organs. This recruitment effect could not be promoted by granulocyte colony-stimulating factor (G-CSF), suggests a different mobilization mechanism from ones G-CSF takes effect on hematopoietic cells. Our results proposed nestin+ BMDCs as mobilized candidates in skin injury repair, which provide a new insight of endogenous MSCs therapy.

Negative regulation of endogenous protein kinase Cα on the dynamic change of carbachol-induced intracellular calcium response in different melanoma cells†

Regulations of intracellular protein kinase C (PKC) on carbachol (CCh)‐induced intracellular calcium ([Ca2+]i) responses were investigated in different stages of melanoma cells. We found that CCh (1 mM) significantly increased [Ca2+]i with 6‐, 4‐, 4‐, and 25‐folds intensities in WM793B, 451Lu, SK‐MEL‐5, and A2058 melanoma cells, respectively. Pretreatment of phorbol 12, 13‐dibutyrate (PDBu, 2 µM), an activator of intracellular PKC, significantly suppressed CCh‐induced peak reactions in WM793B, SK‐MEL‐5, and A2058 cells. RT‐PCR data showed that mRNA levels of PKCα were 12‐, 4‐, 6‐, and 0.9‐folds higher in above four melanoma cells. Short interfering RNA (siRNA) targeting to PKCα in WM793B cells enhanced CCh‐induced peak calcium reactions. Present data indicated that CCh‐induced [Ca2+]i responses were dynamically changed in different stages of melanoma progression. Moreover, intracellular PKCα activated by exogenous agonist and expressed through endogenous gene transcription negatively regulated CCh‐induced calcium responses. The functional analysis on the relationship between CCh‐induced calcium response and endogenous PKCα expression might be helpful to predict the development of melanoma. J. Cell. Physiol. 221: 276–282, 2009.