Human periodontal ligament cells (hPDLCs) possess stem cell properties, which play a key role in periodontal regeneration. Physical stimulation at appropriate intensities such as low-intensity pulsed ultrasound (LIPUS) enhances cell proliferation and osteogenic differentiation of mesechymal stem cells. However, the impacts of LIPUS on osteogenic differentiation of hPDLCs in vitro and its molecular mechanism are unknown. This study was undertaken to investigate the effects of LIPUS on osteogenic differentiation of hPDLCs. HPDLCs were isolated from premolars of adolescents for orthodontic reasons, and exposed to LIPUS at different intensities to determine an optimal LIPUS treatment dosage. Dynamic changes of alkaline phosphatase (ALP) activities in the cultured cells and supernatants, and osteocalcin production in the supernatants after treatment were analyzed. Runx2 and integrin β1 mRNA levels were assessed by reverse transcription polymerase chain reaction analysis after LIPUS stimulation. Blocking antibody against integrinβ1 was used to assess the effects of integrinβ1 inhibitor on LIPUS-induced ALP activity, osteocalcin production as well as calcium deposition. Our data showed that LIPUS at the intensity of 90 mW/cm2 with 20 min/day was more effective. The ALP activities in lysates and supernatants of LIPUS-treated cells started to increase at days 3 and 7, respectively, and peaked at day 11. LIPUS treatment significantly augmented the production of osteocalcin after day 5. LIPUS caused a significant increase in the mRNA expression of Runx2 and integrin β1, while a significant decline when the integrinβ1 inhibitor was used. Moreover, ALP activity, osteocalcin production as well as calcium nodules of cells treated with both daily LIPUS stimulation and integrinβ1 antibody were less than those in the LIPUS-treated group. In conclusion, LIPUS promotes osteogenic differentiation of hPDLCs, which is associated with upregulation of Runx2 and integrin β1, which may thus provide therapeutic benefits in periodontal tissue regeneration.

The administration of ketamine with concurrent noxious stimulation results in the attenuation of the neuroapoptotic response. These findings suggest that concurrent surgery and procedural pain attenuates ketamine-induced neuroapoptosis.

BackgroundUrea, the end product of protein metabolism, has been considered to have negligible toxicity for a long time. Our previous study showed a depression phenotype in urea transporter (UT) B knockout mice, which suggests that abnormal urea metabolism may cause depression. The purpose of this study was to determine if urea accumulation in brain is a key factor causing depression using clinical data and animal models.MethodsA meta-analysis was used to identify the relationship between depression and chronic diseases. Functional Magnetic Resonance Imaging (fMRI) brain scans and common biochemical indexes were compared between the patients and healthy controls. We used behavioural tests, electrophysiology, and molecular profiling techniques to investigate the functional role and molecular basis in mouse models.FindingsAfter performing a meta-analysis, we targeted the relevance between chronic kidney disease (CKD) and depression. In a CKD mouse model and a patient cohort, depression was induced by impairing the medial prefrontal cortex. The enlarged cohort suggested that urea was responsible for depression. In mice, urea was sufficient to induce depression, interrupt long-term potentiation (LTP) and cause loss of synapses in several models. The mTORC1-S6K pathway inhibition was necessary for the effect of urea. Lastly, we identified that the hydrolysate of urea, cyanate, was also involved in this pathophysiology.InterpretationThese data indicate that urea accumulation in brain is an independent factor causing depression, bypassing the psychosocial stress. Urea or cyanate carbamylates mTOR to inhibit the mTORC1-S6K dependent dendritic protein synthesis, inducing impairment of synaptic plasticity in mPFC and depression-like behaviour. CKD patients may be able to attenuate depression only by strict management of blood urea.

Cutaneous squamous cell carcinoma (SCC) is one of the most common non‐melanoma skin cancers worldwide. While its exact tumorigenesis mechanisms is far from well‐established and less satisfied therapeutic strategy can be clinically used nowadays. In this study, we intended to investigate the role of DNA damage‐inducible transcript 4 (DDIT4) in human SCC. Firstly, we identified DDIT4 is significantly suppressed in human SCC tissue and cultured A431 cell line, and reduced DDIT4 accelerates keratinocytes proliferation but impedes the autophagy flux through mTORC1 pathway by affecting the downstream S6 Kinase1, 4E‐BP1, Beclin1 and LC3 II/I. While 1,25(OH)2D3 enhanced DDIT4 expression and activated autophagy and inhibit mTORC1 to take the effect of anti‐proliferation and activating autophagy. Further, formation of direct vitamin D receptor (VDR)‐DDIT4 transcription complex was verified by ChIP‐qPCR, which showed the molecular mechanism of how 1,25(OH)2D3 promotes DDIT4 transcription. Thirdly, xenograft tumor‐bearing mice model treated by gradient concentrations of 1,25(OH)2D3 revealed the obvious anti‐carcinoma effect of 1,25(OH)2D3 in vivo and DDIT4 acted the molecular vector of 1,25(OH)2D3 through mTORC1. Lastly, elevated DDIT4 expression was verified in human actinic keratoses tissue, and chronic long‐term ultraviolet (UV) irradiation on mouse disclosed UV could promote DDIT4 expression inside epidermis. Conclusively, our research suggested a novel molecular mechanism about the human SCC tumorigenesis and the pharmacological mechanism about how 1,25(OH)2D3 take its anti‐carcinoma role on human SCC, as well as a striking paradoxes that how UV irradiation plays the tumorigenesis effect but synchronously take a protective role in the early stage of SCC carcinogenesis.

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