Extracellular matrix stiffness as an energy metabolism regulator drives osteogenic differentiation in mesenchymal stem cells.

The biophysical factors of biomaterials such as their stiffness regulate stem cell differentiation. Energy metabolism has been revealed an essential role in stem cell lineage commitment. However, whether and how extracellular matrix (ECM) stiffness regulates energy metabolism to determine stem cell differentiation is less known. Here, the study reveals that stiff ECM promotes glycolysis, oxidative phosphorylation, and enhances antioxidant defense system during osteogenic differentiation in MSCs. Stiff ECM increases mitochondrial fusion by enhancing mitofusin 1 and 2 expression and inhibiting the dynamin-related protein 1 activity, which contributes to osteogenesis. Yes-associated protein (YAP) impacts glycolysis, glutamine metabolism, mitochondrial dynamics, and mitochondrial biosynthesis to regulate stiffness-mediated osteogenic differentiation. Furthermore, glycolysis in turn regulates YAP activity through the cytoskeletal tension-mediated deformation of nuclei. Overall, our findings suggest that YAP is an important mechanotransducer to integrate ECM mechanical cues and energy metabolic signaling to affect the fate of MSCs. This offers valuable guidance to improve the scaffold design for bone tissue engineering constructs.

Early Predicting Osteogenic Differentiation of Mesenchymal Stem Cells Based on Deep Learning Within One Day.

Osteogenic differentiation of mesenchymal stem cells (MSCs) is proposed to be critical for bone tissue engineering and regenerative medicine. However, the current approach for evaluating osteogenic differentiation mainly involves immunohistochemical staining of specific markers which often can be detected at day 5-7 of osteogenic inducing. Deep learning (DL) is a significant technology for realizing artificial intelligence (AI). Computer vision, a branch of AI, has been proved to achieve high-precision image recognition using convolutional neural networks (CNNs). Our goal was to train CNNs to quantitatively measure the osteogenic differentiation of MSCs. To this end, bright-field images of MSCs during early osteogenic differentiation (day 0, 1, 3, 5, and 7) were captured using a simple optical phase contrast microscope to train CNNs. The results showed that the CNNs could be trained to recognize undifferentiated cells and differentiating cells with an accuracy of 0.961 on the independent test set. In addition, we found that CNNs successfully distinguished differentiated cells at a very early stage (only 1 day). Further analysis showed that overall morphological features of MSCs were the main basis for the CNN classification. In conclusion, MSCs differentiation detection can be achieved early and accurately through simple bright-field images and DL networks, which may also provide a potential and novel method for the field of cell detection in the near future.

Mechanical memory based on chromatin and metabolism remodeling promotes proliferation and smooth muscle differentiation in mesenchymal stem cells.

Stem cells respond and remember mechanical cues from the microenvironment, which modulates their therapeutic effects. Chromatin organization and energy metabolism regulate the stem cell fate induced by mechanical cues. However, the mechanism of mechanical memory is still unclear. This study aimed to investigate the effects of mechanical amplitude, frequency, duration, and stretch cycle on mechanical memory in mesenchymal stem cells. It showed that the amplitude was the dominant parameter to the persistence of cell alignment. F-actin, paxillin, and nuclear deformation are more prone to be remolded than cell alignment. Stretching induces transcriptional memory, resulting in greater transcription upon subsequent reloading. Cell metabolism displays mechanical memory with sustained mitochondrial fusion and increased ATP production. The mechanical memory of chromatin condensation is mediated by histone H3 lysine 27 trimethylation, leading to much higher smooth muscle differentiation efficiency. Interestingly, mechanical memory can be transmitted based on direct cell-cell interaction, and stretched cells can remodel the metabolic homeostasis of static cells. Our results provide insight into the underlying mechanism of mechanical memory and its potential benefits for stem cell therapy.

Coupling of Perinuclear Actin Cap and Nuclear Mechanics in Regulating Flow-Induced Yap Spatiotemporal Nucleocytoplasmic Transport.

Mechanical forces, including flow shear stress, govern fundamental cellular processes by modulating nucleocytoplasmic transport of transcription factors like Yes-associated Protein (YAP). However, the underlying mechanical mechanism remains elusive. In this study, it is reported that unidirectional flow induces biphasic YAP transport with initial nuclear import, followed by nuclear export as actin cap formation and nuclear stiffening. Conversely, pathological oscillatory flow induces slight actin cap formation, nuclear softening, and sustained YAP nuclear localization. To elucidate the disparately YAP spatiotemporal distribution, a 3D mechanochemical model is developed, which integrates flow sensing, cytoskeleton organization, nucleus mechanotransduction, and YAP transport. The results unveiled that despite the significant localized nuclear stress imposed by the actin cap, its inherent stiffness counteracts the dispersed contractile stress exerted by conventional fibers on the nuclear membrane. Moreover, alterations in nuclear stiffness synergistically regulate nuclear deformation, thereby governing YAP transport. Furthermore, by expanding the single-cell model to a collective vertex framework, it is revealed that the irregularities in actin cap formation within individual cells have the potential to induce topological defects and spatially heterogeneous YAP distribution in the cellular monolayer. This work unveils a unified mechanism of flow-induced nucleocytoplasmic transport, providing a linkage between transcription factor localization and mechanical stimulation.

[Differentiation of stem cells regulated by biophysical cues].

Stem cells have been regarded with promising application potential in tissue engineering and regenerative medicine due to their self-renewal and multidirectional differentiation abilities. However, their fate is relied on their local microenvironment, or niche. Recent studied have demonstrated that biophysical factors, defined as physical microenvironment in which stem cells located play a vital role in regulating stem cell committed differentiation. In vitro, synthetic physical microenvironments can be used to precisely control a variety of biophysical properties. On this basis, the effect of biophysical properties such as matrix stiffness, matrix topography and mechanical force on the committed differentiation of stem cells was further investigated. This paper summarizes the approach of mechanical models of artificial physical microenvironment and reviews the effects of different biophysical characteristics on stem cell differentiation, in order to provide reference for future research and development in related fields.

Cuticular competing endogenous RNAs regulate insecticide penetration and resistance in a major agricultural pest.

BACKGROUND: The continuously developing pesticide resistance is a great threat to agriculture and human health. Understanding the mechanisms of insecticide resistance is a key step in dealing with the phenomenon. Insect cuticle is recently documented to delay xenobiotic penetration which breaks the previous stereotype that cuticle is useless in insecticide resistance, while the underlying mechanism remains scarce. RESULTS: Here, we find the integument contributes over 40.0% to insecticide resistance via different insecticide delivery strategies in oriental fruit fly. A negative relationship exists between cuticle thickening and insecticide penetration in resistant/susceptible, also in field strains of oriental fruit fly which is a reason for integument-mediated resistance. Our investigations uncover a regulator of insecticide penetration that miR-994 mimic treatment causes cuticle thinning and increases susceptibility to malathion, whereas miR-994 inhibitor results in opposite phenotypes. The target of miR-994 is a most abundant cuticle protein (CPCFC) in resistant/susceptible integument expression profile, which possesses capability of chitin-binding and influences the cuticle thickness-mediated insecticide penetration. Our analyses find an upstream transcriptional regulatory signal of miR-994 cascade, long noncoding RNA (lnc19419), that indirectly upregulates CPCFC in cuticle of the resistant strain by sponging miR-994. Thus, we elucidate the mechanism of cuticular competing endogenous RNAs for regulating insecticide penetration and demonstrate it also exists in field strain of oriental fruit fly. CONCLUSIONS: We unveil a regulatory axis of lnc19419 ~ miR-994 ~ CPCFC on the cuticle thickness that leads to insecticide penetration resistance. These findings indicate that competing endogenous RNAs regulate insecticide resistance by modulating the cuticle thickness and provide insight into the resistance mechanism in insects.

Mechanically sensitive HSF1 is a key regulator of left-right symmetry breaking in zebrafish embryos.

The left-right symmetry breaking of vertebrate embryos requires nodal flow. However, the molecular mechanisms that mediate the asymmetric gene expression regulation under nodal flow remain elusive. Here, we report that heat shock factor 1 (HSF1) is asymmetrically activated in the Kupffer's vesicle of zebrafish embryos in the presence of nodal flow. Deficiency in HSF1 expression caused a significant situs inversus and disrupted gene expression asymmetry of nodal signaling proteins in zebrafish embryos. Further studies demonstrated that HSF1 is a mechanosensitive protein. The mechanical sensation ability of HSF1 is conserved in a variety of mechanical stimuli in different cell types. Moreover, cilia and Ca2+-Akt signaling axis are essential for the activation of HSF1 under mechanical stress in vitro and in vivo. Considering the conserved expression of HSF1 in organisms, these findings unveil a fundamental mechanism of gene expression regulation by mechanical clues during embryonic development and other physiological and pathological transformations.

Frizzled-9 triggers actin polymerization and activates mechano-transducer YAP to rescue simulated microgravity-induced osteoblast dysfunction.

Long-term spaceflight can result in bone loss and osteoblast dysfunction. Frizzled-9 (Fzd9) is a Wnt receptor of the frizzled family that is vital for osteoblast differentiation and bone formation. In the present study, we elucidated whether Fzd9 plays a role in osteoblast dysfunction induced by simulated microgravity (SMG). After 1-7 days of SMG, osteogenic markers such as alkaline phosphatase (ALP), osteopontin (OPN), and Runt-related transcription factor 2 (RUNX2) were decreased, accompanied by a decrease in Fzd9 expression. Furthermore, Fzd9 expression decreased in the rat femur after 3 weeks of hindlimb unloading. In contrast, Fzd9 overexpression counteracted the decrease in ALP, OPN, and RUNX2 induced by SMG in osteoblasts. Moreover, SMG regulated phosphorylated glycogen synthase kinase-3ß (pGSK3ß) and ß-catenin expression or sublocalization. However, Fzd9 overexpression did not affect pGSK3ß and ß-catenin expression or sublocalization induced by SMG. In addition, Fzd9 overexpression regulated protein kinase B also known as Akt and extracellular signal-regulated kinase (ERK) phosphorylation and induced F-actin polymerization to form the actin cap, press the nuclei, and increase nuclear pore size, thereby promoting the nuclear translocation of Yes-associated protein (YAP). Our study findings provide mechanistic insights into the role of Fzd9 in triggering actin polymerization and activating YAP to rescue SMG-induced osteoblast dysfunction and suggest that Fzd9 is a potential target to restore osteoblast function in individuals with bone diseases and after spaceflight.

An Antenna-Abundant Glutathione S-Transferase BdGSTd8 Participates in Detoxification of Two Organophosphorus Insecticides in Bactrocera dorsalis (Hendel).

The oriental fruit fly, Bactrocera dorsalis, is a damaging insect pest for many vegetable and fruit crops that has evolved severe chemical insecticide resistance, including organophosphorus, neonicotinoid, pyrethroid, and macrolides. Hence, it is important to elucidate its detoxification mechanism to improve its management and mitigate resource destruction. Glutathione S-transferase (GST) is a critical secondary phase enzyme that plays multiple detoxification functions against xenobiotics. In this study, we identified several BdGSTs by characterizing their potential relationships with five insecticides using inducible and tissue-specific expression pattern analyses. We found that an antenna-abundant BdGSTd8 responded to four different classes of insecticides. Subsequently, our immunohistochemical and immunogold staining analysis further confirmed that BdGSTd8 was primarily located in the antenna. Our investigations also confirmed that BdGSTd8 possesses the capability to enhance cell viability by directly interacting with malathion and chlorpyrifos, which clarified the function of antenna-abundant GST in B. dorsalis. Altogether, these findings enrich our understanding of GST molecular characteristics in B. dorsalis and provide new insights into the detoxification of superfluous xenobiotics in the insect antenna.

Wnt/ß-catenin plays a dual function in calcium hydroxide induced proliferation, migration, osteogenic differentiation and mineralization in vitro human dental pulp stem cells.

AIM: Calcium hydroxide is the gold standard material for pulp capping and has been widely used in clinical dentistry. Calcium hydroxide promotes proliferation, migration and osteogenic differentiation of dental pulp stem cells (DPSCs). However, the underlying mechanism is not clear. Our study investigated the role of Wnt/ß-catenin pathway in calcium hydroxide-induced proliferation, migration, osteogenic differentiation and mineralization of human DPSCs. METHODOLOGY: Protein and gene expression was detected by western blot (WB), immunofluorescence staining and quantitative real-time PCR (qPCR). Cell viability was analysed using the Cell Counting Kit-8 (CCK-8) assay. Wound-healing assay was used to analyse cell migration. The expression of alkaline phosphatase (ALP) was detected using ALP staining. Mineralization was analysed by alizarin red staining. RESULTS: Calcium hydroxide increased the protein expression of phosphorylated-GSK3ß/GSK3ß, ß-catenin and the gene expression of LEF-1. Inhibition of Wnt/ß-catenin abolished calcium hydroxide-induced proliferation and migration of DPSCs in 24 h. However, incubation with calcium hydroxide for 7 days and 14 days reduced Wnt/ß-catenin signalling. Inhibition of Wnt/ß-catenin promoted calcium hydroxide-induced osteogenic differentiation and mineralization in DPSCs. CONCLUSION: Wnt/ß-catenin pathway plays a dual role in calcium hydroxide-regulated DPSC behaviour. Incubation with calcium hydroxide promoted rapid proliferation and migration of DPSCs, while prolonged incubation negatively regulated osteogenic differentiation and mineralization.

Pulse Capacitive Coupling Electric Field Regulates Cell Migration, Proliferation, Polarization, and Vascularization to Accelerate Wound Healing.

Objectives: Accelerating wound healing using continuous exogenous electrical stimulation is limited due to some serious side effects, including thermal damage. Many previous studies based on direct current contact stimulation may cause chemical burns or blisters, thereby increasing patients suffering. The aim of this study was to develop a safer and more convenient pulse capacitive coupling electrical field (PCCEF) stimulation to accelerate wound healing. Approach: A PCCEF-generating platform was self-designed to facilitate wound healing. The promoting effects and appropriate pulse width were explored by applying PCCEFs (54 mV/mm, 60 Hz) of different pulse widths to various cells involved in wound healing and mouse models for 2 h daily. Results: PCCEFs of ≥10 µs pulse width showed marked promotion of the migration and proliferation of human dermal fibroblasts and HaCaT cells, enhanced the M2-type polarization and YPA/TAZ expression of macrophages, and facilitated the wound healing of mouse models. Comprehensive histological results suggested that PCCEF of 100 µs pulse width exerted the most positive effects. Innovation: A safe and effective PCCEF was developed to promote wound healing, which prevented prolonged stimulation and averted direct contact. Conclusion: PCCEF accelerated wound healing, especially at the optimal 100 µs pulse width, and was expected to be translated to clinical application, helping alleviate patient suffering, while reducing side effects.

Cell senescence alters responses of porcine trabecular meshwork cells to shear stress.

Mechanical microenvironment and cellular senescence of trabecular meshwork cells (TMCs) are suspected to play a vital role in primary open-angle glaucoma pathogenesis. However, central questions remain about the effect of shear stress on TMCs and how aging affects this process. We have investigated the effect of shear stress on the biomechanical properties and extracellular matrix regulation of normal and senescent TMCs. We found a more significant promotion of Fctin formation, a more obvious realignment of F-actin fibers, and a more remarkable increase in the stiffness of normal cells in response to the shear stress, in comparison with that of senescent cells. Further, as compared to normal cells, senescent cells show a reduced extracellular matrix turnover after shear stress stimulation, which might be attributed to the different phosphorylation levels of the extracellular signal-regulated kinase. Our results suggest that TMCs are able to sense and respond to the shear stress and cellular senescence undermines the mechanobiological response, which may lead to progressive failure of cellular TM function with age.

Fluid shear stress promotes periodontal ligament cells proliferation via p38-AMOT-YAP.

Periodontal ligament (PDL) cells are a promising tool for periodontal regeneration therapy. Achieving a sufficient number of PDL cells is essential to PDL regeneration. In our study, appropriate flow shear stress (FSS, 1-6 dyn/cm2) promotes the proliferation of PDL cells. FSS remodels cytoskeleton and focal adhesion in a duration-dependent manner. FSS induces PDL cells to form the actin cap within 10 min, flattens the nuclei, and increases the nuclear pore size, which promotes nuclear translocation of Yes-associated protein (YAP). FSS activates p38, which plays a dual function in YAP regulation. p38 regulates the phosphorylation of Akt and cofilin, as well as induced F-actin polymerization to induce YAP activity. In addition, p38 inhibits pLATS and consecutively regulates angiomotin (AMOT) and YAP phosphorylation. AMOT competitively binds to F-actin and YAP to participate in FSS-mediated YAP nuclear translocation and cell proliferation. Taken collectively, our results provide mechanistic insights into the role of p38-AMOT-YAP in FSS-mediated PDL cells proliferation and indicate potential applications in dental regenerative medicine.

Short-term efficacy, safety and survival of laparoscopic radical resection for colorectal cancer patients with bowel obstruction.

OBJECTIVE: To investigate the short-term efficacy of laparoscopic radical resection for colorectal cancer with bowel obstruction and the effects of the surgery on inflammatory factors for improving the clinical treatment of the condition. METHODS: The data of colorectal cancer patients presenting bowel obstruction (n = 167) treated at our hospital from January 2019 to December 2020 were assessed. The patients were divided into a laparoscopic radical resection of colorectal cancer group (LRRCC, n = 90) and open surgery group (OP, n = 77). Before treatment and on the 1st, 3rd, 5th, 7th and 15th day after treatment, their serum levels of pain factors, neuropeptide Y, prostaglandin E2 and nerve growth factor were measured by a serum biochemistry analyzer, their levels of inflammatory factors including C-reactive protein, interleukin 6 (IL-6), IL-8 and tumor necrosis factor-α by ELISA, and their amount of CD3+, CD4+ and CD8+ T cell subsets were measure by flow cytometry. Anorectal motility was assessed before and 4 and 8 weeks after treatment. Survival rates were assessed using the Kaplan-Meier method. RESULTS: On the 1st, 3rd, 5th, 7th and 15th day after treatment, compared with the OP group, the LRRCC group had lower levels of serum pain factors, inflammatory factors and CD8+T lymphocytes, while their numbers of CD3+ and CD4+ T lymphocytes subsets were significantly increased. Further, the LRRCC group had fewer complications and significantly higher survival rates, demonstrating better efficacy than the OP group. CONCLUSION: Laparoscopic radical resection was effective and achieved superior outcomes than open surgery in treating colorectal cancer patients with bowel obstruction.

IGFBP2 function as a novel biomarker for active lupus nephritis.

In search for new targets for the diagnosis and treatment of lupus nephritis (LN), we employed TMT-liquid chromatography-triple quadrupole mass spectrometry (TMT-LC-MS/MS) combined with RNA-seq and identified a panel of proteins that was dysregulated both at protein level and mRNA level in active LN patients compared with healthy controls. We chose to study the role of IGFBP2 since it is a relatively understudied protein in the context of LN. We further validated that IGFBP2 significantly increased and correlated with SLE activity index in active LN patients. The receiver operator characteristic (ROC) curve suggested that plasma IGFBP2 had a high diagnostic efficiency for distinguishing between inactive and active LN patients (AUC = 0.992; 95% CI = 0.974-1.000; P < 0.001). We demonstrated neutralizing IGFBP2-downregulated CD4+ T cell activation, upregulated the ratio of Treg, downregulated AKT/mTOR/4E-BP1 pathway, and significantly improved nephritis in MRL/lpr mice. In all, our work demonstrated IGFBP2 as a biomarker specific for active LN and blocking IGFBP2 could be a new target for treating LN. KEY MESSAGES : Plasma IGFBP2 is a promising diagnostic marker for distinguishing stable LN from active LN, and it is also a predictor for the poor prognosis of LN. Blockade of IGFBP2 can significantly improve the pathological damage of LN. IGFBP2 may regulate activation of CD4+ T and Treg ratio. Neutralizing IGFBP2 downregulates AKT/mTOR/4E-BP1 pathway.

Static magnetic field regulates proliferation, migration, and differentiation of human dental pulp stem cells by MAPK pathway.

Magnetic materials are now commonly used in dental clinics. These materials generally produce a static magnetic field (SMF). While it is known that SMF can affect cells' behaviors such as proliferation, migration, and differentiation, the mechanisms underlying these effects are still unclear. Our study investigates the role of the mitogen-activated protein (MAP) kinase pathway in SMF-induced proliferation, migration, osteogenic/odontogenic differentiation, and mineralization in human dental pulp stem cells (DPSCs). Human DPSCs were exposed to SMF of 1 mT and the phosphorylated MAP kinases were detected by Western blot analysis. Three MAP kinases inhibitors were pre-cultured with DPSCs and exposed to SMF for 24 h. Cell viability was analyzed using Cell Counting Kit-8. Cell migration was tested by a wound healing assay. Osteogenic/odontogenic differentiation was detected by ALP staining assay, ALP and DSPP Western blot analysis. Mineralization was studied by alizarin red staining analysis. SMF activated phosphorylation of c-Jun N-terminal kinase (JNK), P38 and extracellular signal-regulated kinase (ERK). The inhibition of JNK, P38, and ERK signaling decreased SMF-induced proliferation and migration. ERK and P38 play more important roles in SMF-induced ALP staining and protein expression. JNK was vital for SMF-induced DSPP expression. JNK, P38, and ERK all involved in SMF-mediated mineralization. Our study demonstrated that the MAPK pathway regulated SMF-induced proliferation, migration, osteogenic/odontogenic differentiation, and mineralization in human DPSCs.

Non-contact electrical stimulation as an effective means to promote wound healing.

Electrical stimulation has been demonstrated to have beneficial effects in skin tissue repair. However, most electrical stimulations are applied with percutaneous electrode, which is prone to causing serious trauma. Using non-contact electrical stimulation (NCES) is expected to reduce the potential risk. In this study, NCES was expediently exerted by a self-designed practical device. Electrode plates of 10-cm spacing with appropriate side lengths of 21 and 30 cm were selected by EF distribution analysis for applying NCES to cells and mice, respectively, and the real EF strengths were measured. The change of loading voltage which had no effect on the regular pattern of EF distribution could be used as a single factor to explore the effect of NCES on wound healing. It was subsequently demonstrated that 53 mV mm-1 NCES facilitated the migration and proliferation of HaCaT cells and HDFs in vitro, and the M2-type polarization of macrophages. Moreover, 54 and 84 mV mm-1 NCESs accelerated the wound healing rate of model mice from the perspective of reducing scarring, enhancing collagen synthesis and increasing angiogenesis in vivo. The promoting role of NCES in wound healing showed the potential to initiate new possibilities for the clinical treatment of skin tissue injuries.

Phenytoin Regulates Migration and Osteogenic Differentiation by MAPK Pathway in Human Periodontal Ligament Cells.

INTRODUCTION: Periodontal healing requires an adequate number of periodontal ligament (PDL) cells to rebuild the impaired tissue. Phenytoin (PHT) has been reported to promote wound healing and extracellular matrix deposition, which indicates its promising application of periodontal healing. However, the effects of PHT on PDL cells behavior and the underlying mechanism are still unknown. METHODS: Human PDL cells were cultured and identified. 20-100 µg/mL PHT were used in our study. The proliferation of PDL cells was determined by the EdU assay. A wound healing assay was used to detect cell migration. Matrix metalloproteinase (MMP)-1, MMP-2, tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 expression were analyzed by real time-PCR. The protein expression of MMP-1 and phosphorylated mitogen-activated protein kinases (MAPKs) were detected by western blotting assay. Osteogenic differentiation was assessed by alkaline phosphatase (ALP) staining. RESULTS: We found that 20-100 µg/mL of PHT did not affect PDL cells proliferation, whereas 50-100 µg/mL of PHT inhibited cell migration. The 50 or 100 µg/mL of PHT decreased the gene and protein expression of MMP-1, but increased the gene expression of TIMP-1. MMP-2 and TIMP-2 were not affected by 20-100 µg/mL of PHT. Further, 20-50 µg/mL of PHT increased ALP expression, but 100 µg/mL of PHT depressed ALP expression. The extracellular regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38 were activated by PHT. JNK and ERK are involved in PHT-regulated migration. JNK plays an essential role in PHT-induced osteogenic differentiation. CONCLUSIONS: MAPK pathway involved in PHT-regulated migration and osteogenic differentiation in human PDL cells.

HDAC1 promotes the migration of human myeloma cells via regulation of the lncRNA/Slug axis.

Understanding the mechanisms underlying malignancy in myeloma cells is important for targeted treatment and drug development. Histone deacetylases (HDACs) can regulate the progression of various cancer types; however, their roles in myeloma are not well known. In the present study, the expression of class I HDACs in myeloma cells and tissues was evaluated. Furthermore, the effects of HDAC1 on the migration of myeloma cells and the associated mechanisms were investigated. Among the class I HDACs evaluated, HDAC1 was upregulated in both myeloma cells and tissues. Targeted inhibition of HDAC1 suppressed the migration of myeloma cells. Of the assessed transcription factors, small interfering (si)­HDAC1 decreased the expression of Slug. Overexpression of Slug reversed the si­HDAC1­mediated suppressed migration of myeloma cells. Mechanistically, the results revealed that HDAC1 regulated the mRNA stability of Slug, while it had no effect on its transcription or nuclear export. Furthermore, HDAC1 negatively regulated the expression of long non­coding RNA (lncRNA) NONHSAT113026, which could bind with the 3'­untranslated region of Slug mRNA to facilitate its degradation. The present study demonstrated that HDAC1 promoted the migration of human myeloma cells via regulation of lncRNA/Slug signaling.

Knockdown of a ß-Adrenergic-Like Octopamine Receptor Affects Locomotion and Reproduction of Tribolium castaneum.

The neurohormone octopamine regulates many crucial physiological processes in insects and exerts its activity via typical G-protein coupled receptors. The roles of octopamine receptors in regulating behavior and physiology in Coleoptera (beetles) need better understanding. We used the red flour beetle, Tribolium castaneum, as a model species to study the contribution of the octopamine receptor to behavior and physiology. We cloned the cDNA of a ß-adrenergic-like octopamine receptor (TcOctß2R). This was heterologously expressed in human embryonic kidney (HEK) 293 cells and was demonstrated to be functional using an in vitro cyclic AMP assay. In an RNAi assay, injection of dsRNA demonstrated that TcOctß2R modulates beetle locomotion, mating duration, and fertility. These data present some roles of the octopaminergic signaling system in T. castaneum. Our findings will also help to elucidate the potential functions of individual octopamine receptors in other insects.