Publications by authors named "Daqi Xu"

25 Publications

  • Page 1 of 1

Tpl2 kinase regulates inflammation but not tumorigenesis in mice.

Toxicol Appl Pharmacol 2021 05 13;418:115494. Epub 2021 Mar 13.

Immunology Department, Genentech, Inc., South San Francisco, CA 94080, USA. Electronic address:

Tumor progression locus 2 (Tpl2, gene name MAP3K8), a mitogen-activated protein kinase, is widely expressed in immune and non-immune cells to integrate tumor necrosis factor (TNF), toll-like receptors (TLRs), and interleukin-1 (IL1) receptor signaling to regulate inflammatory response. Given its central role in inflammatory response, Tpl2 is an attractive small molecule drug target. However, the role of Tpl2 as an oncogene or tumor suppressor gene remains controversial, and its function outside immune cells is not understood. We therefore utilized a Tpl2 kinase dead (Tpl2-KD) mouse model in an 18-month aging study to further elucidate Tpl2 effects on lifespan and chronic disease. Histopathological studies revealed the incidence and severity of spontaneous tumors and non-neoplastic lesions were comparable between wild type and Tpl2-KD mice. The only finding was that male Tpl2-KD mice had higher bodyweight and an increased incidence of liver steatosis, suggesting a sex-specific role for Tpl2 in hepatic lipid metabolism. In conclusion, loss of Tpl2 kinase activity did not lead to increased tumorigenesis over aging in mice but affected likely alterations in lipid metabolism in male animals.
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http://dx.doi.org/10.1016/j.taap.2021.115494DOI Listing
May 2021

Mucosal CD8 T Cell Responses Are Shaped by Batf3-DC After Foodborne Infection.

Front Immunol 2020 11;11:575967. Epub 2020 Sep 11.

Department of Microbiology and Immunology, Center for Infectious Diseases, Stony Brook University Renaissance School of Medicine, Stony Brook, NY, United States.

While immune responses have been rigorously examined after intravenous () infection, less is understood about its dissemination from the intestines or the induction of adaptive immunity after more physiologic models of foodborne infection. Consequently, this study focused on early events in the intestinal mucosa and draining mesenteric lymph nodes (MLN) using foodborne infection of mice with modified to invade murine intestinal epithelium (InlA . InlA trafficked intracellularly from the intestines to the MLN and were associated with Batf3-independent dendritic cells (DC) in the lymphatics. Consistent with this, InlA initially disseminated from the gut to the MLN normally in mice. Activated migratory DC accumulated in the MLN by 3 days post-infection and surrounded foci of InlA . At this time mice displayed reduced InlA burdens, implicating cDC1 in maximal bacterial accumulation in the MLN. mice also exhibited profound defects in the induction and gut-homing of InlA -specific effector CD8 T cells. Restoration of pathogen burden did not rescue antigen-specific CD8 T cell responses in mice, indicating a critical role for in generating anti-InlA immunity following foodborne infection. Collectively, these data suggest that DC play diverse, dynamic roles in the early events following foodborne InlA infection and in driving the establishment of intestinal -specific effector T cells.
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http://dx.doi.org/10.3389/fimmu.2020.575967DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7518468PMC
June 2021

The kinase IRAK4 promotes endosomal TLR and immune complex signaling in B cells and plasmacytoid dendritic cells.

Sci Signal 2020 06 2;13(634). Epub 2020 Jun 2.

Research, Genentech, 1 DNA Way, South San Francisco, CA 94080, USA.

The dysregulation of multiple signaling pathways, including those through endosomal Toll-like receptors (TLRs), Fc gamma receptors (FcγR), and antigen receptors in B cells (BCR), promote an autoinflammatory loop in systemic lupus erythematosus (SLE). Here, we used selective small-molecule inhibitors to assess the regulatory roles of interleukin-1 receptor (IL-1R)-associated kinase 4 (IRAK4) and Bruton's tyrosine kinase (BTK) in these pathways. The inhibition of IRAK4 repressed SLE immune complex- and TLR7-mediated activation of human plasmacytoid dendritic cells (pDCs). Correspondingly, the expression of interferon (IFN)-responsive genes (IRGs) in cells and in mice was positively regulated by the kinase activity of IRAK4. Both IRAK4 and BTK inhibition reduced the TLR7-mediated differentiation of human memory B cells into plasmablasts. TLR7-dependent inflammatory responses were differentially regulated by IRAK4 and BTK by cell type: In pDCs, IRAK4 positively regulated NF-κB and MAPK signaling, whereas in B cells, NF-κB and MAPK pathways were regulated by both BTK and IRAK4. In the pristane-induced lupus mouse model, inhibition of IRAK4 reduced the expression of IRGs during disease onset. Mice engineered to express kinase-deficient IRAK4 were protected from both chemical (pristane-induced) and genetic (NZB/W_F1 hybrid) models of lupus development. Our findings suggest that kinase inhibitors of IRAK4 might be a therapeutic in patients with SLE.
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http://dx.doi.org/10.1126/scisignal.aaz1053DOI Listing
June 2020

Function of CSF1 and IL34 in Macrophage Homeostasis, Inflammation, and Cancer.

Front Immunol 2019 4;10:2019. Epub 2019 Sep 4.

Genentech, South San Francisco, CA, United States.

Colony-stimulating factor 1 (CSF1) and interleukin 34 (IL34) signal the CSF1 receptor to regulate macrophage differentiation. Studies in IL34- or CSF1-deficient mice have revealed that IL34 function is limited to the central nervous system and skin during development. However, the roles of IL34 and CSF1 at homeostasis or in the context of inflammatory diseases or cancer in wild-type mice have not been clarified . By neutralizing CSF1 and/or IL34 in adult mice, we identified that they play important roles in macrophage differentiation, specifically in steady-state microglia, Langerhans cells, and kidney macrophages. In several inflammatory models, neutralization of both CSF1 and IL34 contributed to maximal disease protection. However, in a myeloid cell-rich tumor model, CSF1 but not IL34 was required for tumor-associated macrophage accumulation and immune homeostasis. Analysis of human inflammatory conditions reveals IL34 upregulation that may account for the protection requirement of IL34 blockade. Furthermore, evaluation of IL34 and CSF1 blockade treatment during infection reveals no substantial safety concerns. Thus, IL34 and CSF1 play non-redundant roles in macrophage differentiation, and therapeutic intervention targeting IL34 and/or CSF1 may provide an effective treatment in macrophage-driven immune-pathologies.
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http://dx.doi.org/10.3389/fimmu.2019.02019DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6736990PMC
October 2020

Anatomic reconstruction of anterior talofibular ligament with tibial tuberosity-patellar tendon autograft for chronic lateral ankle instability.

J Orthop Surg (Hong Kong) 2018 May-Aug;26(2):2309499018780874

1 Department of Sports Medicine, Xiangya Hospital, Central South University, Changsha, China.

Introduction: Anatomic repair of the anterior talofibular ligament (ATFL) is challenging when the local ligamentous tissue is severely attenuated. Anatomic reconstruction of the ATFL with tibial tuberosity-patellar tendon (TT-PT) autograft is a feasible choice that can avoid the complicated tendon-bone healing and restore ankle stability.

Materials And Methods: From 2009 to 2015, 31 chronic lateral ankle instability (CLAI) patients (31 ankles), who had a serious injury on the ATFL only, were treated with anatomic reconstruction of ATFL with TT-PT. American orthopedic foot and ankle society ankle-hindfoot score (AHS), visual analog scale for pain score (VAS), Karlsson-Peterson score, Tegner activity level, and objective examination comprehending range of motion were used to evaluate the clinical outcomes before and after operation. Radiographically, talar tilt angles and anterior drawer were assessed in pre- and postoperative ankle stress views.

Results: Among the 31 ankles, 17 ankles with single-bundle ATFL and 14 ankles with double-bundle ATFL were found at operation. At a mean follow-up of 42 months (24-82 months), all patients were satisfied with the procedure. Mean AHS significantly increased from 60.5 ± 8.2 to 93.5 ± 4.8. Mean Karlsson-Peterson score significantly increased from 55.2 ± 11.0 preoperatively to 91.2 ± 6.9 at final follow-up. Average VAS significantly decreased from 5.9 ± 1.6 preoperatively to 1.4 ± 1.0 at the latest follow-up. Mean Tegner activity level was 3.7 ± 0.9 before operation, compared with 7.0 ± 0.8 after operation. On stress radiographs, mean talar tilt angle was 17.0 ± 3.4° before operation and 3.8 ± 2.1° at the latest follow-up. In addition, mean anterior tibiotalar translation was 7.5 ± 2.2 mm before operation and 1.8 ± 1.1 mm at the latest follow-up.

Conclusion: Anatomic reconstruction of the ATFL using a TT-PT autograft allows bone-bone healing in talus and tendon-tendon/periosteum healing in fibula rather than requiring tendon-bone healing, which is an alternative choice for treating CLAI caused by single ATFL insufficiency.
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http://dx.doi.org/10.1177/2309499018780874DOI Listing
September 2019

Effects of Combined Magnetic Fields Treatment and Nano-Hydroxyapatite Coating on Porous Biphasic Calcium Phosphate Bone Graft in Rabbit Spinal Fusion Model.

Spine (Phila Pa 1976) 2018 06;43(11):E625-E633

Central South University Xiangya Hospital, Orthopedic Institute of Central South University, Changsha, P.R. China.

Study Design: An animal experimental study was designed to investigate the efficacy of combined magnetic fields (CMF) treatment and nano-hydroxyapatite (HA) coating in the biphasic calcium phosphate (BCP) graft in posterolateral lumbar fusion.

Objective: To evaluate the effects of CMF treatment and nano-HA/BCP and their combination effect in posterolateral lumbar fusion.

Summary Of Background Data: Enhancement of artificial bone graft bioeffects could improve spinal fusion outcomes. The bone graft integration is vital in spinal fusion, nano-HA coating, and CMF treatment were reported as effective methods to improve bone graft integration.

Methods: A bilateral transverse process fusion model was performed on 32 rabbits. The CMF treatment was performed for 30 minutes per day postoperation. The fusion rate, new bone formation, artificial bone graft-autologous bone fusion interface in x-ray and scanning electron microscopy, biomechanics property of fusion rate, histological fusion condition, artificial bone residual rate, and immunohistochemistry assessment of bone morphogenetic protein 2 (BMP-2) and Transforming growth factor beta 1 (TGF-β1) expression were observed at 9th week after surgery.

Results: CMF treatment and nano-HA coating increased the fusion rate, adjusted optical density index, intensity of binding of artificial and autologous bone, bone growth rate, and bending stiffness. CMF treatment also significantly increased BMP-2 and TGF-β1 expression in fusion region while nano-HA coating significantly decreased artificial bone residual rate.

Conclusion: Our findings suggest that porous nano-HA/BCP graft could significantly improve spine fusion outcome with excellent bioactivity, biocompatibility and degradability and CMF treatment could significantly improve spine fusion outcome by improving bioactivity and biocompatibility of artificial bone graft in rabbit. Combination of CMF treatment with nano-HA/BCP graft could significantly increase posterolateral lumbar fusion rate in rabbit, which would be a potential strategy for spine fusion preclinical study.

Level Of Evidence: N/A.
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http://dx.doi.org/10.1097/BRS.0000000000002463DOI Listing
June 2018

TPL2 kinase action and control of inflammation.

Pharmacol Res 2018 03 26;129:188-193. Epub 2017 Nov 26.

Genentech Research, Genentech Inc., 1 DNA Way, South San Francisco, CA, 94080, USA. Electronic address:

Tumor progression locus 2 (TPL2, also known as COT or MAP3K8) is a mitogen-activated protein kinase kinase (MAP3K) activated downstream of TNFαR, IL1R, TLR, CD40, IL17R, and some GPCRs. TPL2 regulates the MEK1/2 and ERK1/2 pathways to regulate a cascade of inflammatory responses. In parallel to this, TPL2 also activates p38α and p38δ to drive the production of various inflammatory mediators in neutrophils. We discuss the implications of this finding in the context of various inflammatory diseases.
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http://dx.doi.org/10.1016/j.phrs.2017.11.031DOI Listing
March 2018

Low-Intensity Pulsed Ultrasound Stimulation for Tendon-Bone Healing: A Dose-Dependent Study.

Am J Phys Med Rehabil 2018 04;97(4):270-277

From the Department of Sports Medicine, Key Laboratory of Organ Injury, Aging and Regenerative Medicine of Hunan Province, Research Center of Sports Medicine, Xiangya Hospital, Central South University, Changsha, China (HL, FL, CC, ZW, HC, JQ, TZ, DX); and Department of Spine Surgery, Key Laboratory of Organ Injury, Aging and Regenerative Medicine of Hunan Province, Research Center of Sports Medicine, Xiangya Hospital, Central South University, Changsha, China (JH).

Objective: The aim of the study was to evaluate the dosage effect of low-intensity pulsed ultrasound stimulation on tendon-bone healing.

Design: Standard partial patellectomies were performed on 120 mature New Zealand rabbits randomly assigned into the following three groups: a control group (daily mock sonication, 20 mins), a qd group (daily ultrasonication, 20 mins), and a bid group (ultrasonication twice a day, 20 mins each time). The rabbits were killed 8 or 16 wks postoperatively, and the microarchitectural, histological, and mechanical properties of the patella-patellar tendon interface were evaluated.

Results: Microcomputed tomography analysis showed that the bid group exhibited more new bone formation and mineralization than the other groups in the tendon-bone healing position at both 8 and 16 wks postoperatively. Histological assessments confirmed that the bid group exhibited a significantly better patella-patellar tendon interface than the other groups, as shown by the increased formation and remodeling of newly formed bone and a fibrocartilage layer. The biomechanical properties of the regenerated patella-patellar tendon interface significantly improved in the bid group.

Conclusions: Low-intensity pulsed ultrasound stimulation treatment twice a day was more effective than the once-a-day treatment on tendon-bone healing.
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http://dx.doi.org/10.1097/PHM.0000000000000844DOI Listing
April 2018

Initiation Timing of Low-Intensity Pulsed Ultrasound Stimulation for Tendon-Bone Healing in a Rabbit Model.

Am J Sports Med 2016 Oct 29;44(10):2706-2715. Epub 2016 Jun 29.

Department of Sports Medicine, Research Center of Sports Medicine, Xiangya Hospital, Central South University, Changsha, China Department of Spine Surgery, Research Center of Sports Medicine, Xiangya Hospital, Central South University, Changsha, China

Background: Low-intensity pulsed ultrasound stimulation (LIPUS) has been proven to be a beneficial biophysical therapy for tendon-bone (T-B) healing. However, the optimal time to initiate LIPUS treatment has not been determined yet. LIPUS initiated at different stages of the inflammatory phase may profoundly affect T-B healing.

Purpose: An established rabbit model was used to preliminarily investigate the effect of LIPUS initiation timing on T-B healing.

Study Design: Controlled laboratory study.

Methods: A total of 112 mature rabbits that underwent partial patellectomy were randomly assigned to 4 groups: daily mock sonication (control group) and daily ultrasonication started immediately postoperatively (immediate group), on postoperative day 7 (7-day delayed group), or on postoperative day 14 (14-day delayed group). Peripheral leukocyte counts at the inflammatory phase were used to assess postoperative inflammation. The rabbits were sacrificed at 8 or 16 weeks postoperatively for microarchitectural, histological, and mechanical evaluations of the patella-patellar tendon (PPT) junction.

Results: The biomechanical properties of the PPT junction were significantly improved in the LIPUS-treated groups. Significantly higher ultimate strength and stiffness were seen in the 7-day delayed group compared with the other groups at 8 weeks postoperatively (P < .05 for all). Newly formed bone expansion from the remaining patella in the ultrasonic treatment groups was significantly increased and remodeled compared with the control group. Micro-computed tomography analysis showed that the 7-day delayed group had significantly more bone volume and bone mineral content at the interface as compared with the other groups at 8 weeks postoperatively (P < .05 for all). Histologically, the ultrasonic treatment groups exhibited a significantly better PPT junction, as shown by more formation and remodeling of the fibrocartilage layer and newly formed bone. Additionally, peripheral leukocyte counts displayed a significant increase from postoperative day 1 to day 3 in the immediate group as compared with the other groups. Furthermore, postoperative hydrarthrosis was more likely in the immediate group.

Conclusion: LIPUS started at postoperative day 7 had a more prominent effect on T-B healing compared with the other treatment regimens in this study.

Clinical Relevance: The findings of the study may help optimize the initiation timing of LIPUS for T-B healing.
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http://dx.doi.org/10.1177/0363546516651863DOI Listing
October 2016

T cell-intrinsic S1PR1 regulates endogenous effector T-cell egress dynamics from lymph nodes during infection.

Proc Natl Acad Sci U S A 2016 Feb 9;113(8):2182-7. Epub 2016 Feb 9.

Department of Immunology, University of Connecticut Health, Farmington, CT 06030; Department of Pediatrics, University of Connecticut Health, Farmington, CT 06030

Viral clearance requires effector T-cell egress from the draining lymph node (dLN). The mechanisms that regulate the complex process of effector T-cell egress from the dLN after infection are poorly understood. Here, we visualized endogenous pathogen-specific effector T-cell migration within, and from, the dLN. We used an inducible mouse model with a temporally disrupted sphingosine-1-phosphate receptor-1 (S1PR1) gene specifically in endogenous effector T cells. Early after infection, WT and S1PR1(-/-) effector T cells localized exclusively within the paracortex. This localization in the paracortex by CD8 T cells was followed by intranodal migration by both WT and S1PR1(-/-) T cells to positions adjacent to both cortical and medullary lymphatic sinuses where the T cells exhibited intense probing behavior. However, in contrast to WT, S1PR1(-/-) effector T cells failed to enter the sinuses. We demonstrate that, even when LN retention signals such as CC chemokine receptor 7 (CCR7) are down-regulated, T cell intrinsic S1PR1 is the master regulator of effector T-cell emigration from the dLN.
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http://dx.doi.org/10.1073/pnas.1516485113DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4776484PMC
February 2016

The effect of low-intensity pulsed ultrasound on bone-tendon junction healing: Initiating after inflammation stage.

J Orthop Res 2016 10 18;34(10):1697-1706. Epub 2016 Feb 18.

Department of Spine Surgery, Research Center of Sports Medicine, Xiangya Hospital, Central South University, Changsha, 410008, China.

The purpose of this study was to explore the effect of low-intensity pulsed ultrasound (LIPUS) treatment initiating after inflammation stage on the process of bone-tendon junction (BTJ) healing in a rabbit model. Thirty-six rabbits undergoing partial patellectomy were randomly divided into two groups: control and LIPUS. The period of initial inflammatory stage is 2 weeks. So LIPUS treatment was initiated at postoperative week 2 and continued until the patella-patellar tendon (PPT) complexes were harvested at postoperative weeks 4, 8, and 16. At each time point, the PPT complexes were harvested for qRT-PCR, histology, radiographs, synchroton radiation micro computed tomography (SR-µCT), and biomechanical testing. The qRT-PCR results showed that LIPUS treatment beginning at postoperative week 2 played an anti-inflammatory role in BTJ healing. Histologically, the LIPUS group showed more advanced remodeling of the lamellar bone and marrow cavity than the control group. The area and length of the new bone in the LIPUS group were significantly greater than the control group at postoperative weeks 8 and 16. SR-µCT demonstrated that new bone formation and remodeling in the LIPUS group were more advanced than the control group. Biomechanical test results demonstrated that the failure load, ultimate strength and energy at failure were significantly higher than those of the control group. In conclusion, LIPUS treatment beginning at postoperative week 2 was able to accelerate bone formation during the bone-tendon junction healing process and significantly improved the healing quality of BTJ injury. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1697-1706, 2016.
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http://dx.doi.org/10.1002/jor.23180DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6084317PMC
October 2016

The therapeutic potential of regulatory T cells for the treatment of autoimmune disease.

Expert Opin Ther Targets 2015 16;19(8):1091-103. Epub 2015 Apr 16.

University of California San Francisco, Diabetes Center , San Francisco, CA 94143 , USA +1 415 476 4451 ;

Introduction: Immune tolerance remains the holy grail of therapeutic immunology in the fields of organ and tissue transplant rejection, autoimmune diseases, and allergy and asthma. We have learned that FoxP3(+)CD4(+) regulatory T cells play a vital role in both the induction and maintenance of self-tolerance.

Areas Covered: In this opinion piece, we highlight regulatory T cells (Treg) cell biology and novel immune treatments to take advantage of these cells as potent therapeutics. We discuss the potential to utilize Treg and Treg-friendly therapies to replace current general immunosuppressives and induce tolerance as a path towards a drug-free existence without associated toxicities.

Expert Opinion: Finally, we opine on the fact that biomedicine sits on the cusp of a new revolution: the use of human cells as versatile therapeutic engines. We highlight the challenges and opportunities associated with the development of a foundational cellular engineering science that provides a systematic framework for safely and predictably regulating cellular behaviors. Although Treg therapy has become a legitimate clinical treatment, development of the therapy will require a better understanding of the underlying Treg biology, manufacturing advances to promote cost effectiveness and combinations with other drugs to alter the pathogenicity/regulatory balance.
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http://dx.doi.org/10.1517/14728222.2015.1037282DOI Listing
January 2017

Innate antiviral host defense attenuates TGF-β function through IRF3-mediated suppression of Smad signaling.

Mol Cell 2014 Dec;56(6):723-37

Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, Department of Cell and Tissue Biology, University of California at San Francisco, CA 94143, USA. Electronic address:

TGF-β signaling is essential in many processes, including immune surveillance, and its dysregulation controls various diseases, including cancer, fibrosis, and inflammation. Studying the innate host defense, which functions in most cell types, we found that RLR signaling represses TGF-β responses. This regulation is mediated by activated IRF3, using a dual mechanism of IRF3-directed suppression. Activated IRF3 interacts with Smad3, thus inhibiting TGF-β-induced Smad3 activation and, in the nucleus, disrupts functional Smad3 transcription complexes by competing with coregulators. Consequently, IRF3 activation by innate antiviral signaling represses TGF-β-induced growth inhibition, gene regulation and epithelial-mesenchymal transition, and the generation of Treg effector lymphocytes from naive CD4(+) lymphocytes. Conversely, silencing IRF3 expression enhances epithelial-mesenchymal transition, TGF-β-induced Treg cell differentiation upon virus infection, and Treg cell generation in vivo. We present a mechanism of regulation of TGF-β signaling by the antiviral defense, with evidence for its role in immune tolerance and cancer cell behavior.
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http://dx.doi.org/10.1016/j.molcel.2014.11.027DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4273650PMC
December 2014

Enhanced patella-patellar tendon healing using combined magnetic fields in a rabbit model.

Am J Sports Med 2014 Oct 28;42(10):2495-501. Epub 2014 Jul 28.

Department of Sports Medicine, Research Center of Sports Medicine, Xiangya Hospital, Central South University, Changsha, China

Background: A combined magnetic field (CMF) is a composite of a dynamic sinusoidal magnetic field and a magnetostatic field. Stimuli from CMFs has proved to be an effective tool for healing problem fractures and spinal fusion procedures.

Hypothesis: Combined magnetic field technology will enhance healing of bone-tendon junction repair via endochondral ossification for regeneration of the fibrocartilage zone.

Study Design: Controlled laboratory study.

Methods: Forty-eight mature rabbits were randomly divided into CMF-treated and placebo-treated (control) groups. A partial patellectomy model was created. The CMF-treated group was subjected to CMF stimulation from the third postoperative day for 30 minutes per day up to weeks 8 or 16. At each time point, tissue samples were harvested and evaluated biomechanically and histomorphologically. The area of newly formed bone and the thickness of fibrocartilage were measured in hematoxylin and eosin-stained sections and toluidine blue-stained sections, respectively, while the density of fibrocartilage cells and the amount of proteoglycans were calculated using safranin O-stained sections. A biomechanical analysis was carried out to ascertain tensile strength.

Results: Quantitative histological measurements showed that the newly formed bone and regenerated fibrocartilage zone in the CMF-treated group increased by a respective 99.2% and 41.9% compared with the control group at week 8 and a respective 97.8% and 22.8% at week 16. In the CMF-treated group at postoperative week 16, the amount of proteoglycans was 36.9% more than that of the control group, but the density of fibrocartilage cells was just 71.4% of the control group; there were no significant differences at week 8. Mechanical test results showed that energy to failure was not significantly different between the 2 groups at week 8. Yet, at week 16, load to failure, ultimate strength, and energy to failure in the CMF-treated group (311.0 ± 59.4 N, 8.46 ± 1.41 MPa, and 0.87 ± 0.17 J, respectively) were significantly higher than those in the control group (247.1 ± 65.6 N, 6.84 ± 1.12 MPa, and 0.52 ± 0.15 J, respectively).

Conclusion: Biophysical stimulation with CMFs enhances healing after bone-tendon junction injuries in a rabbit model.

Clinical Relevance: These results demonstrate the feasibility of using CMFs for stimulating bone-tendon healing after repair.
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http://dx.doi.org/10.1177/0363546514541539DOI Listing
October 2014

Clinical outcomes of remnant preserving augmentation in anterior cruciate ligament reconstruction: a systematic review.

Knee Surg Sports Traumatol Arthrosc 2014 Sep 2;22(9):1976-85. Epub 2013 Nov 2.

Department of Sports Medicine and Research Center of Sports Medicine, Xiangya Hospital, Central South University, Changsha, 410008, People's Republic of China.

Purpose: The objective of this study was to systematically review the current evidence to see whether the remnant preservation techniques could obtain better clinical outcomes than the standard anterior cruciate ligament reconstruction procedure.

Methods: The authors systematically searched online databases to identify the studies which compared the remnant preservation techniques with the standard techniques. Two reviewers independently extracted data and evaluated the methodological quality of each study. Clinical outcomes in terms of knee stability, clinical scores, vascularization, proprioception, tibial tunnel enlargement and complications were qualitatively compared.

Results: Thirteen studies met the inclusion criteria for review. Compared with the standard procedure, significantly better results regarding knee stability in the remnant preserving group were reported in two of nine studies in the instrumented knee laxity, one of eight studies in the Lachman test and none of eight studies regarding the pivot shift test. Five studies assessed International Knee Documentation Committee scores but found no differences. One of two studies indicated significantly earlier revascularization according to the signal/noise quotient value of the graft on magnetic resonance imaging. One of two studies indicated significantly better proprioceptive function in terms of joint position sense using the reproduction of passive positioning test. Two of two studies showed significantly less tibial tunnel enlargement in the remnant preserving group. None of the studies showed significant increase in the risk of cyclops lesion formation and the loss of knee range of motion in the remnant augmentation group.

Conclusions: The current evidence suggests that the short-term clinical outcomes of patients with the remnant augmentation technique are comparable, if not superior, with that of patients undergoing the standard technique, although it is insufficient to justify the remnant preserving augmentation as a routine treatment for anterior cruciate ligament ruptures.

Level Of Evidence: Systematic review, Level IV.
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http://dx.doi.org/10.1007/s00167-013-2749-8DOI Listing
September 2014

Combined application of low-intensity pulsed ultrasound and functional electrical stimulation accelerates bone-tendon junction healing in a rabbit model.

J Orthop Res 2014 Feb 17;32(2):204-9. Epub 2013 Oct 17.

Department of Sports Medicine, Research Center of Sports Medicine, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, P.R., China; Department of Spine Surgery, Xiangya Hospital, Central South University, Changsha, Hunan, P.R., China.

The objective of this study was to elucidate the combined use of low-intensity pulsed ultrasound (LIPUS) and functional electrical stimulation (FES) on patella-patellar tendon (PPT) junction healing using a partial patellectomy model in rabbits. LIPUS was delivered continuously starting day 3 postoperative until week 6. FES was applied on quadriceps muscles to induce tensile force to the repaired PPT junction 5 days per week for 6 weeks since week 7 postoperatively. Forty rabbits with partial patellectomy were randomly divided into four groups: control, LIPUS alone, FES alone, and LIPUS + FES groups. At week 12, the PPT complexes were harvested for histology, radiographs, peripheral quantitative computed tomography, and biomechanical testing. There was better remodeling of newly formed bone and fibrocartilage zone in the three treatment groups compared with the control group. LIPUS and/or FES treatments significantly increased the area and bone mineral content of new bone. The failure load and ultimate strength of PPT complex were also highly improved in the three treatment groups. More new bone formed and higher tensile properties were showed in the LIPUS + FES group compared with the LIPUS or FES alone groups. Early LIPUS treatment and later FES treatment showed the additive effects of accelerating PPT junction healing.
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http://dx.doi.org/10.1002/jor.22505DOI Listing
February 2014

[Histomorphological analyse of accelerating the fibrocartilage layer repair of patella-patellar tendon junction in rabbits by low intensity pulsed ultrasound stimulation].

Zhong Nan Da Xue Xue Bao Yi Xue Ban 2013 Aug;38(8):838-42

Department of Sports Medicine, Xiangya Hospital, Central South University, Changsha 410008; Department of Spinal Surgery, Central Hospital of Yongzhou, Yongzhou Hunan 425000,China.

Objective: To analyse the effect of low intensity pulsed ultrasound stimulation (LIPUS) on accelerating the fibrocartilage layer repair of patella-patellar tendon junction.

Methods: A total of 60 mature female New Zealand white rabbits undergoing standard partial patellectomy were divided into 2 groups randomly. The control group was given comfort treatment and the treatment group was given LIPUS treatment starting from day 3 to the end of week 6 postoperatively. The scheduled time points of animal euthanization would be at week 6, week 12 and week 18 postoperatively. The patella-patellar tendon (PPT) complex would be harvested and cut into sections after decalcification for H&E staining, Safranine o/fast green staining. The thickness and gray value of fibrocartilage layer were analyzed by SANO Microscope Partner image analyzer.

Results: At week 6, week 12 and week 18 postoperatively, the fibrocartilage layer in the treatment group was significantly thicker than that in the control group (P<0.01), and the gray value of fibrocartilage layer was significantly smaller than that in the control group (P<0.01).

Conclusion: LIPUS helps to accelerate the fibrocartilage layer repair of patella-patellar tendon junction in rabbit models.
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http://dx.doi.org/10.3969/j.issn.1672-7347.2013.08.013DOI Listing
August 2013

A potential new pathway for PD-L1 costimulation of the CD8-T cell response to Listeria monocytogenes infection.

PLoS One 2013 11;8(2):e56539. Epub 2013 Feb 11.

Department of Immunology, University of Connecticut Health Center, Farmington, Connecticut, United States of America.

Programmed death ligand-1 (PD-L1) is an important negative regulator of T cell immune responses via interactions with PD-1 and CD80. However, PD-L1 can also act as a positive costimulator, but the relevant counterreceptor is not known. We analyzed the role of PD-L1 in CD8-T cell responses to infection with Listeria monocytogenes (LM) or vesicular stomatitis virus (VSV). PD-L1 blockade impaired antigen-specific CD8 effector T cell expansion in response to LM, but not to VSV infection, particularly limiting short-lived effector cell differentiation. Simultaneous CD4-T cell depletion and anti-PD-L1 blockade revealed that PD-L1 provided costimulation even in the absence of CD4-T cells. Most importantly, specific blockade of PD-L1 binding to CD80 or to PD-1 did not recapitulate PDL-1 blockade. The results suggested that PD-L1 plays an important costimulatory role for antigen-specific CD8 T cells during LM infection perhaps through a distinct receptor or interaction epitope.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0056539PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3569435PMC
July 2013

Allograft versus autograft for anterior cruciate ligament reconstruction: an up-to-date meta-analysis of prospective studies.

Int Orthop 2013 Feb 4;37(2):311-20. Epub 2012 Dec 4.

Department of Sports Medicine, Research Center of Sports Medicine, Xiangya Hospital, Central South University, Changsha, 410008, People's Republic of China.

Purpose: Although a large number of anterior cruciate ligament (ACL) reconstructions are performed annually, there remains a considerable amount of controversy over whether an autograft or an allograft should be used. The aim of this meta-analysis was to compare the clinical outcomes of allograft and autograft in primary ACL reconstruction.

Methods: The authors systematically searched electronic databases to identify prospective studies which compared allografts with autografts for primary ACL reconstruction. The results of the eligible studies were analysed in terms of instrumented laxity measurements, Lachman test, Pivot Shift test, objective International Knee Documentation Committee (IKDC) Scores, Lysholm Scores, Tegner Scores, and clinical failures. Study quality was assessed and relevant data were extracted independently by two reviewers. A random effect model was used to pool the data. Statistical heterogeneity between trials was evaluated by the chi-square and I-square tests.

Results: Nine studies, with 410 patients in the autograft and 408 patients in the allograft group, met the inclusion criteria. Five studies compared bone-patellar tendon-bone (BPTB) grafts, and four compared soft-tissue grafts. Four studies were randomized controlled trials, and five were prospective cohort studies. The results of the meta-analysis showed that there were no significant differences between allograft and autograft on all the outcomes in terms of instrumented laxity measurements (P=0.59), Lachman test (P=0.41), Pivot Shift test (P=0.88), objective IKDC Scores (P=0.87), Lysholm Scores (P=0.79), Tegner Scores (P=0.06), and clinical failures (P=0.68). These findings were still robust during the sensitivity analysis. However, a subgroup analysis of Tegner scores by involving only BPTB grafts showed a statistical difference in favour of autografts (P=0.005).

Conclusions: There was insufficient evidence to identify which of the two types of grafts was significantly better for ACL reconstruction, though the subgroup analysis indicated that reconstruction with BPTB autograft might allow patients to return to higher levels of activity in comparison with BPTB allograft. More high-quality randomized controlled trials with specified age and activity level are highly required before drawing a reliable conclusion.
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http://dx.doi.org/10.1007/s00264-012-1720-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3560895PMC
February 2013

[Effect of tetramethylpyrazine on the expression of macrophage migration inhibitory factor in acute spinal cord injury in rats].

Zhong Nan Da Xue Xue Bao Yi Xue Ban 2012 Oct;37(10):1031-6

Department of Spinal Surgery, Central South Universtiy, Changsha, China.

Objective: To determine the effect of tetramethylpyrazine (TMP) on the expression of migration inhibitory factor (MIF) in acute spinal cord injury (ASCI) in rats.

Methods: Allen's weight-drop method was used to establish a rat model of ASCI at T10. A total of 110 adult SD rats were divided into a sham operation group (group S, n=10), a control group (group C, n=50), and a TMP group (group T, n=50). Spinal cord functionality was measured by a modified Rivilin loxotic plate degree, BBB score, and combined behavioral score (CBS) at 1, 3, 5, 7, 14 and 21 d postoperatively. The injured spinal cord tissue samples were harvested at 1, 3, 6, 12 h and 1, 3, 5, 7, 14, 21 d postoperatively (n=5 at each time point) and used to prepare continuous histological sections, in which the expression of MIF was analyzed by immunohistochemistry.

Results: The degree in group T measured by modified Rivlin loxotic plate test after the ASCI was significantly higher than that in group C at 7, 14, and 21 d (P<0.05). BBB score in group T was significantly higher than that in group C at 5, 7, 14, and 21 d after the ASCI (P<0.05). CBS score in group C was significantly higher than that in group T at 5, 7, 14, and 21 d after the ASCI (P<0.05). The significantly low number of MIF positive cells was shown in group T when compared with that in group C at 12 h and 1, 3, 5, 7 d after the ASCI (P<0.05). As time passed, there was negative correlation between modified Rivlin loxotic plate degree and MIF expression and also between BBB score and MIF, and there was positive correlation between CBB score and MIF expression.

Conclusion: TMP has protective effect after the ASCI, and may promote the repair of injured spinal cord tissues. TMP may decrease the MIF expression in cells after the ASCI.
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http://dx.doi.org/10.3969/j.issn.1672-7347.2012.10.011DOI Listing
October 2012

Upregulation of MetC is essential for D-alanine-independent growth of an alr/dadX-deficient Escherichia coli strain.

J Bacteriol 2011 Mar 30;193(5):1098-106. Epub 2010 Dec 30.

Department of Protein Expression, Novo Nordisk A/S, Novo Nordisk Park, DK-2760 Maaloev, Denmark.

D-Alanine is a central component of the cell wall in most prokaryotes. D-Alanine synthesis in Escherichia coli is carried out by two different alanine racemases encoded by the alr and dadX genes. Deletion of alr and dadX from the E. coli genome results in a D-alanine auxotrophic phenotype. However, we have observed growth of prototrophic phenotypic revertants during routine culturing of a D-alanine auxotrophic strain. We present a detailed comparison of the proteome and transcriptome profiles of the D-alanine auxotroph and a prototrophic revertant strain. Most noticeably, a general upregulation of genes involved in methionine synthesis in the revertant strain was detected. The appearance of the revertant phenotype was genetically linked to point mutations in the methionine repressor gene (metJ). Our results reveal an alternative metabolic pathway which can supply essential d-alanine for peptidoglycan synthesis of alr- and dadX-deficient E. coli mutants and provide evidence for significant alanine racemase coactivity of the E. coli cystathionine beta-lyase (MetC).
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http://dx.doi.org/10.1128/JB.01027-10DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3067588PMC
March 2011

[Effectiveness comparison of two surgical procedures on lumbar disc protrusion].

Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi 2010 Aug;24(8):908-12

Department of Spinal Surgery, Xiangya Hospital, Central South University, 410008 PR China.

Objective: To compare the effectiveness of microdiscectomy and macrodiscectomy on the single-level lumbar disc protrusion (LDP).

Methods: Between November 2002 and October 2005, 241 patients with LDP underwent 2 surgical procedures: microdiscectomy (group A, 93 cases) and macrodiscectomy (group B, 148 cases). All patients had single-level LDP. In group A, there were 51 males and 42 females with an average age of 32.3 years (range, 18-47 years); there were 23 cases of protrusion, 52 cases of prolapse, and 18 cases of sequestration with an average disease duration of 8.5 months (range, 1-18 months), including 8 cases at L2,3 level, 11 cases at L3,4 level, 35 cases at L4,5 level, and 39 cases at L5, S1 level. In group B, there were 81 males and 67 females with an average age of 31.8 years (range, 16-50 years); there were 37 cases of protrusion, 85 cases of prolapse, and 26 cases of sequestration with an average disease duration of 9.3 months (range, 1-20 months), including 9 cases at L2,3 level, 15 cases at L3,4 level, 63 cases at L4,5 level, and 61 cases at L5, S1 level. There was no significant difference in age, sex, segment level, type, or disease duration between 2 groups (P > 0.05).

Results: Immediate back and sciatic pain relief was achieved in 225 (93.4%) patients after operation. The satisfactory rates were 91.4% in group A and 87.8% in group B at 1 week after operation, showing no significant difference (P > 0.05). The length of incision, amount of bleeding, amount of drainage, and hospitalization time in group A were significantly fewer than those in group B (P < 0.05); while the operative time in group A was longer than that in group B, but showing no significant difference (P > 0.05). Dural laceration occurred in 4 cases of group A and 5 cases of group B, superficial infections of incision occurred in 5 cases of group B and intervertebral space infections occurred in 4 cases of group B, and epidural hematoma occurred in 1 case of group A. The perioperative complication rate (5.4%, 5/93) in group A was significantly lower (P < 0.05) than that in group B (9.5%, 14/148). LDP recurred in 4 cases (4.3%) of group A and in 9 cases (6.1%) of group B postoperatively, showing no significant difference (P > 0.05); of them, 11 cases received second operation and 2 cases were treated conservatively. All cases were followed up 36-77 months (mean, 51.4 months). There were significant differences in visual analog scale (VAS) and Oswestry disability index (ODI) between 2 groups at the last follow-up and preoperation (P > 0.05), but there was significant difference in VAS at 1 week postoperatively between 2 groups (P < 0.05). VAS and ODI were obviously improved at 1 week and last follow-up when compared with preoperation (P < 0.05). There was no significant difference in the improvement rates of VAS and ODI between 2 groups at last follow-up (P > 0.05). According to clinical evaluation of Modified Macnab criteria, the excellent and good rate was 90.3% in group A and 86.5% in group B at final follow-up (P > 0.05).

Conclusion: Both macrodiscectomy and microdiscectomy are effective for LDP, furthermore microdiscectomy is less invasive than macrodiscectomy. Microdiscectomy is recommended to treat single-level LDP.
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August 2010

High level expression, purification and activation of human dipeptidyl peptidase I from mammalian cells.

Protein Expr Purif 2011 Mar 7;76(1):59-64. Epub 2010 Sep 7.

Beijing Novo Nordisk Pharmaceuticals Sci & Tech Co. Ltd., Beijing 102206, China.

Dipeptidyl peptidase I (DPPI) plays a crucial role in maturation of many regulatory peptides and has been suggested as a pharmaceutical target in several inflammatory diseases. It is also a useful processing enzyme for the generation of authentic protein products by catalyzing the removal of N-terminal fusion peptides. We used a robust transient transfection system in human embryonic kidney 293 cells to exploit expression and activation of DPPI from chicken, rat and man for the development of an industrial production process. The expression of human and rat DPPI was significantly higher in the human HEK293 cell line than that obtained with avian DPPI. A CHO K1SV stable cell line was selected as the optimal stable host system for production of human DPPI yielding expression levels higher than 1.5 g/L. The secreted pro-DPPI underwent auto-maturation during defined buffer conditions during the purification steps. Active human DPPI was purified with a three-step purification strategy employing: Butyl Sepharose 4 Fast Flow, Sephadex G-25 Medium and Q Sepharose Fast Flow chromatography. The final yield of active enzyme was approximately 1 g/L cell culture. The enzyme exhibited exopeptidase activity against both a dipeptide-p-nitroanilide substrate and N-terminally extended MEAE-hGH (Met-Glu-Ala-Glu-human growth hormone). In conclusion, an efficient production process for recombinant human DPPI has been developed including a highly efficient and stable CHO cell system and an efficient purification procedure, which is simple and easy to scale for industrial purposes. The present data facilitates not only industrial applications of DPPI as a processing enzyme, but also provides active enzyme useful in the identification of small molecule inhibitors.
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http://dx.doi.org/10.1016/j.pep.2010.09.001DOI Listing
March 2011

[Effect of low-intensity pulsed ultrasound stimulation on maturation of regenerate bone].

Zhong Nan Da Xue Xue Bao Yi Xue Ban 2009 Oct;34(10):984-90

Department of Sports Medicine, Xiangya Hospital, Research Center of Sports Medicine, Central South University, Changsha, China.

Objective: To explore the effect of low intensity pulsed ultrasound stimulation (LIPUS) on the maturation of regenerate bone in a rabbit limb lengthening model.

Methods: Sixty skeletal mature female New Zealand white rabbits were randomly divided into an LIPUS treatment group and a control group. All rabbits were underwent mid-diaphyseal tibial osteotomy and immobilized in an Orthofix M103 Mini lengther. Gradual distraction at 0.5 mm every 12 h for 10 d was performed at day 7 postoperatively. A 4-week course of LIPUS treatment group was applied over the distraction site for 20 min daily starting immediately after the completion of the distraction only for the treatment group. Rabbits were euthanized and the mid-diaphyseal tibia was harvested for evaluation at 4, 8, and 12 wk after the completion of the bone lengthening protocol. Radiographic analysis was performed to study the formation of bone callus using the ImageJ software at 12 wk after the completion of the bone lengthening protocol. Bone mineral density (BMD) of regenerate bone was measured by Dual energy X-ray absorptiometry (DEXA). Torsional testing to failure was performed on the tibia specimens at 8 and 12 wk after the completion of the bone lengthening protocol.

Results: Radiographic measurement showed higher relative gray scale of bone callus in the LIPUS group than that in the control group at 12 wk (P<0.05). BMD in the LIPUS group was significantly higher than that in control group at 8 and 12 wk (P<0.05). Biomechanical testing showed that the ultimate torque, ultimate torsional stiffness, and energy absorption at failure of regenerated bone at 8 and 12 wk in the LIPUS treatment group were better than those in the control group (P<0.05).

Conclusion: LIPUS as a biophysical stimulation may accelerate the formation and maturation of regenerate bone in rabbit tibia lengthening model.
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October 2009
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