Xiaohao Wu

All Publications

• Loss of Pinch Proteins Causes Severe Degenerative Disc Disease-Like Lesions in Mice AGING AND DISEASE Wu, X., Chen, M., Lin, S., Chen, S., Gu, J., Wu, Y., Qu, M., Gong, W., Yao, Q., Li, H., Zou, X., Chen, D., Xiao, G. 2023

  Abstract

  Degenerative disc disease (DDD) is one of the most common skeletal disorders affecting aged populations. DDD is the leading cause of low back/neck pain, resulting in disability and huge socioeconomic burdens. However, the molecular mechanisms underlying DDD initiation and progression remain poorly understood. Pinch1 and Pinch2 are LIM-domain-containing proteins with crucial functions in mediating multiple fundamental biological processes, such as focal adhesion, cytoskeletal organization, cell proliferation, migration, and survival. In this study, we found that Pinch1 and Pinch2 were both highly expressed in healthy intervertebral discs (IVDs) and dramatically downregulated in degenerative IVDs in mice. Deleting Pinch1 in aggrecan-expressing cells and Pinch2 globally (AggrecanCreERT2; Pinch1fl/fl; Pinch2-/-) caused striking spontaneous DDD-like lesions in lumbar IVDs in mice. Pinch loss inhibited cell proliferation and promotes extracellular matrix (ECM) degradation and apoptosis in lumbar IVDs. Pinch loss markedly enhanced the production of pro-inflammatory cytokines, especially TNFα, in lumbar IVDs and exacerbated instability-induced DDD defects in mice. Pharmacological inhibition of TNFα signaling mitigated the DDD-like lesions caused by Pinch loss. In human degenerative NP samples, reduced expression of Pinch proteins was correlated with severe DDD progression and a markedly upregulated expression of TNFα. Collectively, we demonstrate the crucial role of Pinch proteins in maintaining IVD homeostasis and define a potential therapeutic target for DDD.

  View details for DOI 10.14336/AD.2023.0212

  View details for Web of Science ID 000937440200001

  View details for PubMedID 37196110

• Osteoarthritis: pathogenic signaling pathways and therapeutic targets SIGNAL TRANSDUCTION AND TARGETED THERAPY Yao, Q., Wu, X., Tao, C., Gong, W., Chen, M., Qu, M., Zhong, Y., He, T., Chen, S., Xiao, G. 2023; 8 (1): 56

  Abstract

  Osteoarthritis (OA) is a chronic degenerative joint disorder that leads to disability and affects more than 500 million population worldwide. OA was believed to be caused by the wearing and tearing of articular cartilage, but it is now more commonly referred to as a chronic whole-joint disorder that is initiated with biochemical and cellular alterations in the synovial joint tissues, which leads to the histological and structural changes of the joint and ends up with the whole tissue dysfunction. Currently, there is no cure for OA, partly due to a lack of comprehensive understanding of the pathological mechanism of the initiation and progression of the disease. Therefore, a better understanding of pathological signaling pathways and key molecules involved in OA pathogenesis is crucial for therapeutic target design and drug development. In this review, we first summarize the epidemiology of OA, including its prevalence, incidence and burdens, and OA risk factors. We then focus on the roles and regulation of the pathological signaling pathways, such as Wnt/β-catenin, NF-κB, focal adhesion, HIFs, TGFβ/ΒΜP and FGF signaling pathways, and key regulators AMPK, mTOR, and RUNX2 in the onset and development of OA. In addition, the roles of factors associated with OA, including MMPs, ADAMTS/ADAMs, and PRG4, are discussed in detail. Finally, we provide updates on the current clinical therapies and clinical trials of biological treatments and drugs for OA. Research advances in basic knowledge of articular cartilage biology and OA pathogenesis will have a significant impact and translational value in developing OA therapeutic strategies.

  View details for DOI 10.1038/s41392-023-01330-w

  View details for Web of Science ID 000925731100005

  View details for PubMedID 36737426

  View details for PubMedCentralID PMC9898571

• Kindlin-2 loss in condylar chondrocytes causes spontaneous osteoarthritic lesions in the temporomandibular joint in mice INTERNATIONAL JOURNAL OF ORAL SCIENCE Lai, Y., Zheng, W., Qu, M., Xiao, C. C., Chen, S., Yao, Q., Gong, W., Tao, C., Yan, Q., Zhang, P., Wu, X., Xiao, G. 2022; 14 (1): 33

  Abstract

  The progressive destruction of condylar cartilage is a hallmark of the temporomandibular joint (TMJ) osteoarthritis (OA); however, its mechanism is incompletely understood. Here, we show that Kindlin-2, a key focal adhesion protein, is strongly detected in cells of mandibular condylar cartilage in mice. We find that genetic ablation of Kindlin-2 in aggrecan-expressing condylar chondrocytes induces multiple spontaneous osteoarthritic lesions, including progressive cartilage loss and deformation, surface fissures, and ectopic cartilage and bone formation in TMJ. Kindlin-2 loss significantly downregulates the expression of aggrecan, Col2a1 and Proteoglycan 4 (Prg4), all anabolic extracellular matrix proteins, and promotes catabolic metabolism in TMJ cartilage by inducing expression of Runx2 and Mmp13 in condylar chondrocytes. Kindlin-2 loss decreases TMJ chondrocyte proliferation in condylar cartilages. Furthermore, Kindlin-2 loss promotes the release of cytochrome c as well as caspase 3 activation, and accelerates chondrocyte apoptosis in vitro and TMJ. Collectively, these findings reveal a crucial role of Kindlin-2 in condylar chondrocytes to maintain TMJ homeostasis.

  View details for DOI 10.1038/s41368-022-00185-1

  View details for Web of Science ID 000820636900001

  View details for PubMedID 35788130

  View details for PubMedCentralID PMC9253313

• Kindlin-2 preserves integrity of the articular cartilage to protect against osteoarthritis NATURE AGING Wu, X., Lai, Y., Chen, S., Zhou, C., Tao, C., Fu, X., Li, J., Tong, W., Tian, H., Shao, Z., Liu, C., Chen, D., Bai, X., Cao, H., Xiao, G. 2022; 2 (4): 332-+

  Abstract

  Osteoarthritis (OA) is an aging-related degenerative joint disease with a poorly defined mechanism. Here we report that kindlin-2 is highly expressed in articular chondrocytes and downregulated in the degenerated cartilage of aged mice and patients with OA. Kindlin-2 deletion in articular chondrocytes leads to spontaneous OA and exacerbates instability-induced OA lesions in adult mice. Kindlin-2 deficiency promotes mitochondrial oxidative stress and activates Stat3, leading to Runx2-mediated chondrocyte catabolism. Pharmacological inhibition of Stat3 activation or genetic ablation of Stat3 in chondrocytes reverses aberrant accumulation of Runx2 and extracellular-matrix-degrading enzymes and limits OA deteriorations caused by kindlin-2 deficiency. Deleting Runx2 in chondrocytes reverses structural changes and OA lesions caused by kindlin-2 deletion without downregulating p-Stat3. Intra-articular injection of AAV5-kindlin-2 decelerates progression of aging- and instability-induced knee joint OA in mice. Collectively, we identify a pathway consisting of kindlin-2, Stat3 and Runx2 in articular chondrocytes that is responsible for maintaining articular cartilage integrity and define a potential therapeutic target for OA.

  View details for DOI 10.1038/s43587-021-00165-w

  View details for Web of Science ID 000916577200014

  View details for PubMedID 37117739

  View details for PubMedCentralID 5240031

• Exosomal transfer of osteoclast-derived miRNAs to chondrocytes contributes to osteoarthritis progression NATURE AGING Liu, J., Wu, X., Lu, J., Huang, G., Dang, L., Zhang, H., Zhong, C., Zhang, Z., Li, D., Li, F., Liang, C., Yu, Y., Zhang, B., Chen, L., Lu, A., Zhang, G. 2021; 1 (4): 368-+

  Abstract

  Osteoarthritis (OA) is a prevalent aging-related joint disease lacking disease-modifying therapies. Here, we identified an upregulation of circulating exosomal osteoclast (OC)-derived microRNAs (OC-miRNAs) during the progression of surgery-induced OA in mice. We found that reducing OC-miRNAs by Cre-mediated excision of the key miRNA-processing enzyme Dicer or blocking the secretion of OC-originated exosomes by short interfering RNA-mediated silencing of Rab27a substantially delayed the progression of surgery-induced OA in mice. Mechanistically, the exosomal transfer of OC-miRNAs to chondrocytes reduced the resistance of cartilage to matrix degeneration, osteochondral angiogenesis and sensory innervation during OA progression by suppressing tissue inhibitor of metalloproteinase-2 (TIMP-2) and TIMP-3. Furthermore, systemic administration of a new OC-targeted exosome inhibitor (OCExoInhib) blunted the progression of surgery-induced OA in mice. We suggest that targeting the exosomal transfer of OC-miRNAs to chondrocytes represents a potential therapeutic avenue to tackle OA progression.

  View details for DOI 10.1038/s43587-021-00050-6

  View details for Web of Science ID 000899154800009

  View details for PubMedID 37117596

  View details for PubMedCentralID 6391093

• Comparison of Kindlin-2 deficiency-stimulated osteoarthritis-like lesions induced by Prg4CreERT2 versus AggrecanCreERT2 transgene in mice JOURNAL OF ORTHOPAEDIC TRANSLATION Yao, Q., Gong, W., Wu, X., Gan, D., Tao, C., Lin, S., Qu, M., Ouyang, Z., Chen, M., Hu, X., Xiao, G. 2023; 41: 12-19

  Abstract

  Genetically modified mice are the most useful tools for investigating the gene functions in articular cartilage biology and the pathogenesis of osteoarthritis. The AggrecanCreERT2 mice are one of the most reported mouse lines used for this purpose. The Prg4 (proteoglycan 4) gene encodes the lubricin protein and is expressed selectively in chondrocytes located at the superficial layer of the articular cartilage. While the Prg4GFPCreERT2 knock-in inducible-Cre transgenic mice were generated a while ago, so far, few studies have used this mouse line to perform gene functional studies in cartilage biology.We have recently reported that deleting the Fermt2 gene, which encodes the key focal adhesion protein Kindlin-2, in articular chondrocytes by using the AggrecanCreERT2 transgenic mice, results in spontaneous osteoarthritis (OA) lesions, which highly mimics the human OA pathologies. In this study, we have compared the Kindlin-2 deficiency-caused OA phenotypes induced by Prg4GFPCreERT2 with those caused by AggrecanCreERT2 using imaging and histological analyses.We find that Kindlin-2 protein is deleted in about 75% of the superficial articular chondrocytes in the tamoxifen (TAM)-treated Prg4GFPCreERt2/+; Fermt2fl/fl mice compared to controls. At 6 months after TAM injections, the OARSI scores of AggrecanCreERT2/+; Fermt2fl/fl and Prg4GFPCreERt2/+; Fermt2fl/fl mice were 5 and 3, respectively. The knee joints histological osteophyte and synovitis scores were also significantly decreased in Prg4GFPCreERT2/+; Fermt2fl/fl mice compared to those in AggrecanCreERT2/+; Fermt2fl/fl mice. Furthermore, magnitudes of upregulation of the extracellular matrix-degrading enzymes Mmp13 and hypertrophic chondrocyte markers Col10a1 and Runx2 were decreased in Prg4GFPCreERT2/+; Fermt2fl/fl versus AggrecanCreERT2/+; Fermt2fl/fl mice. We finally examined the susceptibility of Prg4GFPCreERT2/+; Fermt2fl/fl mouse model to surgically induce OA lesions. The pathological features of OA in the TAM-DMM model exhibited significant enhancement in cartilage erosion, proteoglycan loss, osteophyte, and synovitis and an increase in OARSI score in articular cartilage compared with those in corn-oil DMM mice.Kindlin-2 loss causes milder OA-like lesions in Prg4GFPCreERT2/+;Fermt2fl/fl than in AggrecanCreERT2/+; Fermt2fl/fl mice. In contrast, Kindlin-2 loss similarly accelerates the destabilization of the medial meniscus-induced OA lesions in both mice.Translational Potential of this Article: Our study demonstrates that Prg4GFPCreERT2 is a useful tool for gene functional study in OA research. This study provides useful information for investigators to choose appropriate Cre mouse lines for their research in cartilage biology.

  View details for DOI 10.1016/j.jot.2023.05.005

  View details for Web of Science ID 001013545600001

  View details for PubMedID 37292436

  View details for PubMedCentralID PMC10244901

• Pip5k1c Loss in Chondrocytes Causes Spontaneous Osteoarthritic Lesions in Aged Mice AGING AND DISEASE Qu, M., Chen, M., Gong, W., Huo, S., Yan, Q., Yao, Q., Lai, Y., Chen, D., Wu, X., Xiao, G. 2023; 14 (2): 502-514

  Abstract

  Osteoarthritis (OA) is the most common degenerative joint disease affecting the older populations globally. Phosphatidylinositol-4-phosphate 5-kinase type-1 gamma (Pip5k1c), a lipid kinase catalyzing the synthesis of phospholipid phosphatidylinositol 4,5-bisphosphate (PIP2), is involved in various cellular processes, such as focal adhesion (FA) formation, cell migration, and cellular signal transduction. However, whether Pip5k1c plays a role in the pathogenesis of OA remains unclear. Here we show that inducible deletion of Pip5k1c in aggrecan-expressing chondrocytes (cKO) causes multiple spontaneous OA-like lesions, including cartilage degradation, surface fissures, subchondral sclerosis, meniscus deformation, synovial hyperplasia, and osteophyte formation in aged (15-month-old) mice, but not in adult (7-month-old) mice. Pip5k1c loss promotes extracellular matrix (ECM) degradation, chondrocyte hypertrophy and apoptosis, and inhibits chondrocyte proliferation in the articular cartilage of aged mice. Pip5k1c loss dramatically downregulates the expressions of several key FA proteins, including activated integrin β1, talin, and vinculin, and thus impairs the chondrocyte adhesion and spreading on ECM. Collectively, these findings suggest that Pip5k1c expression in chondrocytes plays a critical role in maintaining articular cartilage homeostasis and protecting against age-related OA.

  View details for DOI 10.14336/AD.2022.0828

  View details for Web of Science ID 001031029800021

  View details for PubMedID 37008048

  View details for PubMedCentralID PMC10017150

• Brief research report: Effects of Pinch deficiency on cartilage homeostasis in adult mice FRONTIERS IN CELL AND DEVELOPMENTAL BIOLOGY Wu, X., Lin, S., Liao, R., Yao, Q., Lin, L., Zou, X., Xiao, G. 2023; 11: 1116128

  Abstract

  Pinch1 and Pinch2 are LIM domain-containing proteins with crucial functions in mediating focal adhesion formation. Our previous studies have demonstrated that Pinch1/2 expression is essential for cartilage and bone formation during skeletal development in mice. Loss of Pinch expression (Prx1Cre; Pinch1flox/flox; Pinch2-/-) inhibits chondrocyte proliferation and promotes chondrocyte apoptosis, resulting in severe chondrodysplasia and limb shortening. Based on these observations, we wonder if Pinch proteins have a role in adult cartilage and whether Pinch deficiency will compromise cartilage homeostasis and promote osteoarthritis (OA)-related defects in adult mice. To this end, we generated the AggrecanCreERT2; Pinch1flox/flox; Pinch2-/- mice, in which the Pinch1 gene can be inducibly deleted in aggrecan-expressing chondrocytes by tamoxifen and the Pinch2 gene is globally inactivated. Immunofluorescent staining confirmed that the expression of Pinch proteins was significantly decreased in articular cartilage in tamoxifen-treated adult AggrecanCreERT2; Pinch1flox/flox; Pinch2-/- mice. Unexpectedly, our results showed that Pinch loss did not induce marked abnormalities in articular cartilage and other joint tissues in the knee joints of either adult (10-month-old) mice or aged (17-month-old) mice. In a destabilization of the medial meniscus (DMM)-induced OA model, the surgically-induced OA lesions were comparable between Pinch-deficient mice and control mice. Given the fact that Pinch proteins are essential for chondrogenesis and cartilage formation during skeletal development, these findings suggest that Pinch expression is seemingly not indispensable for adult cartilage homeostasis in mice.

  View details for DOI 10.3389/fcell.2023.1116128

  View details for Web of Science ID 000926068100001

  View details for PubMedID 36743414

  View details for PubMedCentralID PMC9892552

• A Rapid Protocol for Direct Isolation of Osteoclast Lineage Cells from Mouse Bone Marrow. Bio-protocol Dang, L., Li, N., Wu, X., Li, D., Zhang, Z., Zhang, B. T., Lyu, A., Chen, L., Zhang, G., Liu, J. 2022; 12 (5): e4338

  Abstract

  Osteoclast lineage cells (OLCs), including osteoclast precursors (OCPs) and mature osteoclasts (MOCs), participate in bone remodeling and mediate pathologic bone loss. Thus, it is essential to obtain OLCs for exploring their molecular features in both physiological and pathological conditions in vivo. However, the conventional protocols for obtaining OLCs ex vivo are not only time-consuming, but also unable to capture the cellular status of OLCs in vivo. In addition, the current antibody-based isolation approaches, such as fluorescence-/ magnetic-activated cell sorting, are not able to obtain pure osteoclasts because no unique surface antigen for osteoclasts has been identified. Here, we develop a rapid protocol for directly isolating OLCs from mouse bone marrow through magnetic-activated cell sorting (MACS). This protocol can rapidly enrich OCPs and MOCs, respectively, depending on the expression of the distinctive surface markers at their differentiation stages. It is optimized to isolate OLCs from four mice concurrently, of which sorting procedure could be completed within ~5 h.

  View details for DOI 10.21769/BioProtoc.4338

  View details for PubMedID 35592608

  View details for PubMedCentralID PMC8918216

• Kindlin-2 inhibits Nlrp3 inflammasome activation in nucleus pulposus to maintain homeostasis of the intervertebral disc BONE RESEARCH Chen, S., Wu, X., Lai, Y., Chen, D., Bai, X., Liu, S., Wu, Y., Chen, M., Lai, Y., Cao, H., Shao, Z., Xiao, G. 2022; 10 (1): 5

  Abstract

  Intervertebral disc (IVD) degeneration (IVDD) is the main cause of low back pain with major social and economic burdens; however, its underlying molecular mechanisms remain poorly defined. Here we show that the focal adhesion protein Kindlin-2 is highly expressed in the nucleus pulposus (NP), but not in the anulus fibrosus and the cartilaginous endplates, in the IVD tissues. Expression of Kindlin-2 is drastically decreased in NP cells in aged mice and severe IVDD patients. Inducible deletion of Kindlin-2 in NP cells in adult mice causes spontaneous and striking IVDD-like phenotypes in lumbar IVDs and largely accelerates progression of coccygeal IVDD in the presence of abnormal mechanical stress. Kindlin-2 loss activates Nlrp3 inflammasome and stimulates expression of IL-1β in NP cells, which in turn downregulates Kindlin-2. This vicious cycle promotes extracellular matrix (ECM) catabolism and NP cell apoptosis. Furthermore, abnormal mechanical stress reduces expression of Kindlin-2, which exacerbates Nlrp3 inflammasome activation, cell apoptosis, and ECM catabolism in NP cells caused by Kindlin-2 deficiency. In vivo blocking Nlrp3 inflammasome activation prevents IVDD progression induced by Kindlin-2 loss and abnormal mechanical stress. Of translational significance, adeno-associated virus-mediated overexpression of Kindlin-2 inhibits ECM catabolism and cell apoptosis in primary human NP cells in vitro and alleviates coccygeal IVDD progression caused by mechanical stress in rat. Collectively, we establish critical roles of Kindlin-2 in inhibiting Nlrp3 inflammasome activation and maintaining integrity of the IVD homeostasis and define a novel target for the prevention and treatment of IVDD.

  View details for DOI 10.1038/s41413-021-00179-5

  View details for Web of Science ID 000740997300001

  View details for PubMedID 35013104

  View details for PubMedCentralID PMC8748798

• Global, regional and national burden of low back pain 1990-2019: A systematic analysis of the Global Burden of Disease study 2019 JOURNAL OF ORTHOPAEDIC TRANSLATION Chen, S., Chen, M., Wu, X., Lin, S., Tao, C., Cao, H., Shao, Z., Xiao, G. 2022; 32: 49-58

  Abstract

  To comprehensively analyze the global level and trends of prevalence, incidence and years lived with disability (YLDs) for low back pain (LBP) from 1990 to 2019 by age, sex and sociodemographic index (SDI).Publicly available modelled data and methods were obtained from the Global Burden of Diseases (GBD) study 2019, and used to evaluate the global burden of LBP through a systematic analysis.Globally, the age-standardized prevalence, incidence and YLDs rate of LBP were slightly decreased from 1990 to 2019, but the number of the prevalent cases, incident cases and YLDs had substantially increased, and LBP remains the leading cause of YLDs in 2019 worldwide. The number of prevalent cases was increased with age and peaked at the age of 45-54 years for both sexes, and the global prevalence rate was higher in females than in males and increased with age, peaking at the 80-84 age group in both sexes in 2019. Overall, a positive association between the age-standardized YLD rate and SDI was observed over the past thirty years. At the national revel, the United States, Denmark and Switzerland had the three highest levels of age-standardized prevalence, while Zambia, Zimbabwe and Canada showed the highest increase in the age-standardized prevalence during 1990-2019.LBP is a major public health issue globally, and its burden remains high. Increasing population awareness about its risk factors and preventive measures for LBP are needed to reduce the future burden of this condition.Due to the high prevalence and heavy burden of LBP globally, it is important to update its epidemiological data. This systematic analysis provides researchers and healthcare policy makers with up-to-date, comprehensive and comparable information on global LBP burden, which is of clinical translational significance.

  View details for DOI 10.1016/j.jot.2021.07.005

  View details for Web of Science ID 000726789700006

  View details for PubMedID 34934626

  View details for PubMedCentralID PMC8639804

• Kindlin-2 deletion in osteoprogenitors causes severe chondrodysplasia and low-turnover osteopenia in mice JOURNAL OF ORTHOPAEDIC TRANSLATION Wu, X., Qu, M., Gong, W., Zhou, C., Lai, Y., Xiao, G. 2022; 32: 41-48

  Abstract

  Our recent studies demonstrate that the focal adhesion protein Kindlin-2 exerts crucial functions in the mesenchymal stem cells, mature osteoblasts and osteocytes in control of early skeletal development and bone homeostasis in mice. However, whether Kindlin-2 plays a role in osteoprogenitors remains unclear.Mice lacking Kindlin-2 expression in osterix (Osx)-expressing cells (i.e., osteoprogenitors) were generated. Micro-computerized tomography (μCT) analyses, histology, bone histomorphometry and immunohistochemistry were performed to determine the effects of Kindlin-2 deletion on skeletal development and bone mass accrual and homeostasis. Bone marrow stromal cells (BMSCs) from mutant mice (Kindlin-2 fl/fl ; Osx Cre ) and control littermates were isolated and determined for their osteoblastic differentiation capacity.Kindlin-2 was highly expressed in osteoprogenitors during endochondral ossification. Deleting Kindlin-2 expression in osteoprogenitors impaired both intramembranous and endochondral ossifications. Mutant mice displayed multiple severe skeletal abnormalities, including unmineralized fontanel, limb shortening and growth retardation. Deletion of Kindlin-2 in osteoprogenitors impaired the growth plate development and largely delayed formation of the secondary ossification center in the long bones. Furthermore, adult mutant mice displayed a severe low-turnover osteopenia with a dramatic decrease in bone formation which exceeded that in bone resorption. Primary BMSCs isolated from mutant mice exhibited decreased osteoblastic differentiation capacity.Our study demonstrates an essential role of Kinlind-2 expression in osteoprogenitors in regulating skeletogenesis and bone mass accrual and homeostasis in mice.This study reveals that Kindlin-2 through its expression in osteoprogenitor cells controls chondrogenesis and bone mass. We may define a novel therapeutic target for treatment of skeletal diseases, such as chondrodysplasia and osteoporosis.

  View details for DOI 10.1016/j.jot.2021.08.005

  View details for Web of Science ID 000726789700005

  View details for PubMedID 34934625

  View details for PubMedCentralID PMC8639803

• Increased PLEKHO1 within osteoblasts suppresses Smad-dependent BMP signaling to inhibit bone formation during aging AGING CELL Liu, J., Liang, C., Guo, B., Wu, X., Li, D., Zhang, Z., Zheng, K., Dang, L., He, X., Lu, C., Peng, S., Pan, X., Zhang, B., Lu, A., Zhang, G. 2017; 16 (2): 360-376

  Abstract

  Emerging evidence indicates that the dysregulation of protein ubiquitination plays a crucial role in aging-associated diseases. Smad-dependent canonical BMP signaling pathway is indispensable for osteoblastic bone formation, which could be disrupted by the ubiquitination and subsequent proteasomal degradation of Smad1/5, the key molecules for BMP signaling transduction. However, whether the dysregulation of Smad1/5 ubiquitination and disrupted BMP signaling pathway is responsible for the age-related bone formation reduction is still underexplored. Pleckstrin homology domain-containing family O member 1 (PLEKHO1) is a previously identified ubiquitination-related molecule that could specifically target the linker region between the WW domains of Smurf1 to promote the ubiquitination of Smad1/5. Here, we found an age-related increase in the expression of PLEKHO1 in bone specimens from either fractured patients or aging rodents, which was associated with the age-related reduction in Smad-dependent BMP signaling and bone formation. By genetic approach, we demonstrated that loss of Plekho1 in osteoblasts could promote the Smad-dependent BMP signaling and alleviated the age-related bone formation reduction. In addition, osteoblast-specific Smad1 overexpression had beneficial effect on bone formation during aging, which could be counteracted after overexpressing Plekho1 within osteoblasts. By pharmacological approach, we showed that osteoblast-targeted Plekho1 siRNA treatment could enhance Smad-dependent BMP signaling and promote bone formation in aging rodents. Taken together, it suggests that the increased PLEKHO1 could suppress Smad-dependent BMP signaling to inhibit bone formation during aging, indicating the translational potential of targeting PLEKHO1 in osteoblast as a novel bone anabolic strategy for reversing established osteoporosis during aging.

  View details for DOI 10.1111/acel.12566

  View details for Web of Science ID 000395379500018

  View details for PubMedID 28083909

  View details for PubMedCentralID PMC5334543

• Molecular Insight into Gut Microbiota and Rheumatoid Arthritis INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES Wu, X., He, B., Liu, J., Feng, H., Ma, Y., Li, D., Guo, B., Liang, C., Dang, L., Wang, L., Tian, J., Zhu, H., Xiao, L., Lu, C., Lu, A., Zhang, G. 2016; 17 (3): 431

  Abstract

  Rheumatoid arthritis (RA) is a systemic, inflammatory, and autoimmune disorder. Gut microbiota play an important role in the etiology of RA. With the considerable progress made in next-generation sequencing techniques, the identified gut microbiota difference between RA patients and healthy individuals provides an updated overview of the association between gut microbiota and RA. We reviewed the reported correlation and underlying molecular mechanisms among gut microbiota, the immune system, and RA. It has become known that gut microbiota contribute to the pathogenesis of RA via multiple molecular mechanisms. The progressive understanding of the dynamic interaction between gut microbiota and their host will help in establishing a highly individualized management for each RA patient, and achieve a better efficacy in clinical practice, or even discovering new drugs for RA.

  View details for DOI 10.3390/ijms17030431

  View details for Web of Science ID 000373712800039

  View details for PubMedID 27011180

  View details for PubMedCentralID PMC4813281