Faculty Bibliography

Impaired wound healing, as it occurs in diabetes mellitus or long-term corticoid treatment, is commonly associated with disability, diminished quality of life, and high economic costs. Selective agonists of the A2A receptor subtype of adenosine, an endogenous regulator of inflammation, promote tissue repair in animal models, both healthy and with impaired healing. Plasmin-mediated proteolysis of fibrin and other matrix proteins is essential for cell migration at sites of injury. Since adenosine A2A receptor activation increases plasminogen activator release from macrophages and mast cells, we studied the effect of a selective agonist, CGS-21680, on full-thickness excisional wound closure in wild-type, urokinase plasminogen activator (uPA)-deficient, and tissue plasminogen activator (tPA)-deficient mice. Wound closure was impaired in tPA- and uPA-deficient mice as compared with wild-type mice, and topical application of CGS-21680 significantly increased the rate at which wounds closed in wild-type mice and uPA-deficient mice, but not in tPA-deficient mice. Immunostaining of tissue sections showed that tPA was present in endothelial cells and histiocytes by day 3 post-wound and also by day 6. In contrast, uPA was more prominent in these cell types only by day 6 post-wound. Our results confirm that plasminogen activation contributes to wound repair and are consistent with the hypothesis that adenosine A2A receptor activation promotes wound closure by a mechanism that depends upon tPA, but not uPA. Moreover, our results suggest that topical adenosine A2A receptor agonists may be useful in promotion of wound closure in patients with impaired wound healing.

To develop the next generation of translational investigators, New York University School of Medicine (NYUSOM) and the NYU-NYC Health and Hospitals Corporation Clinical and Translational Science Institute (NYU-HHC CTSI) developed the Master's of Science in Clinical Investigation dual-degree (MD/MSCI) program. This 5-year program dedicates 1 year to coursework and biomedical research, followed by a medical school/research overlap year, to prepare students for academic research careers. This paper details the MD/MSCI program's curriculum and approach to mentorship, describes the research/professional interests of students, and reports student productivity. In the first 4 years of the program (2010-2014) 20 students were matriculated; 7 (35%) were women, and 12 (60%) research projects were in surgical specialties. To date, 14 students have applied to residency, and half pursued surgical residency programs. Our students have produced 68 accepted abstracts, 15 abstracts in submission, 38 accepted papers, and 24 papers in submission. Despite the time-limited nature of this program, additional training in research design and implementation has promoted a high level of productivity. We conclude that dual-degree training in medicine and translational research is feasible for medical students and allows for meaningful participation in valuable projects. Follow-up is warranted to evaluate the academic trajectory of these students. Clin Trans Sci 2015; Volume #: 1-6.

INTRODUCTION: This work was undertaken to delineate intracellular signaling pathways for the PDE4 inhibitor apremilast and to examine interactions between apremilast, methotrexate and adenosine A2A receptors (A2AR). METHODS: After apremilast and LPS incubation, intracellular cAMP, TNF-alpha, IL-10, IL-6 and IL-1alpha were measured in the Raw264.7 monocytic murine cell line. PKA, Epac1/2 (signaling intermediates for cAMP) and A2AR knockdowns were performed by shRNA transfection and interactions with A2AR and A2BR, as well as with methotrexate were tested in vitro and in the murine air pouch model. Statistical differences were determined using one or two-way ANOVA or Student's t test. The alpha nominal level was set at 0.05 in all cases. A P value of < 0.05 was considered significant. RESULTS: In vitro, apremilast increased intracellular cAMP and inhibited TNF-alpha release (IC50=104nM) and the specific A2AR-agonist CGS21680 (1muM) increased apremilast potency (IC50=25nM). In this cell line, apremilast increased IL-10 production. PKA, Epac1 and Epac2 knockdowns prevented TNF-alpha inhibition and IL-10 stimulation by apremilast. In the murine air pouch model, both apremilast and MTX significantly inhibited leukocyte infiltration, while apremilast, but not MTX, significantly inhibited TNF-alpha release. The addition of MTX (1 mg/kg) to apremilast (5 mg/kg) yielded no more inhibition of leukocyte infiltration or TNF-alpha release than with apremilast alone. CONCLUSIONS: The immunoregulatory effects of apremilast appear to be mediated by cAMP through the downstream effectors PKA, Epac1, and Epac2. A2AR agonism potentiated TNF-alpha inhibition by apremilast, consistent with the cAMP-elevating effects of that receptor. Because the A2AR is also involved in the anti-inflammatory effects of MTX, the mechanism of action of both drugs involves cAMP-dependent pathways and is therefore partially overlapping in nature.

OBJECTIVE: Adenosine, acting at the A2A receptor, mediates the antiinflammatory effects of methotrexate (MTX) in models of inflammation. We previously reported that A2A receptor ligation diminishes wear particle-driven osteolysis. The aim of this study was to investigate whether MTX treatment could prevent bone resorption caused by inflammatory osteolysis. METHODS: C57BL/6 mice (6-8 weeks old) received intraperitoneal injections of 1 mg/kg MTX (n = 20) or 0.9% saline (n = 10), starting 2 weeks prior to surgical implantation of 3 mg of wear particles (ultrahigh molecular weight polyethylene [UHMWPE] particles). The MTX-treated mice received daily injections of vehicle or ZM241385 at the surgical site until they were killed, 14 days later. XenoLight RediJect Bone Probe 680 was injected intravenously, and fluorescence analysis of the calvaria using an IVIS imaging system was performed to assess bone formation. Micro-computed tomography (micro-CT) and immunostaining for osteoclast and osteoblast markers were performed. RESULTS: Implantation of wear particles induced bone pitting and thinning, as shown by micro-CT. MTX treatment markedly reduced osteolysis, and this effect was abrogated by treatment with the A2A receptor antagonist ZM241385. Implantation of UHMWPE reduced new bone formation, and MTX treatment restored new bone formation, an effect that was completely reversed by treatment with ZM241385. Histologic examination of particle-exposed calvariae demonstrated that MTX prevented accumulation of an inflammatory infiltrate at the site of particle implantation, increased the number of osteoblasts, and reduced the number of osteoclasts at the site of inflammation, an effect that was reversed by treatment with ZM241385. CONCLUSION: MTX reduces inflammatory osteolysis indirectly via stimulation of A2A receptor and may represent a novel approach to enhance orthopedic implant survival, delaying or eliminating the need for revision arthroplasty surgery.

OBJECTIVES: Discuss issues regarding clinical trial design for the development of biosimilars in the European Union and the United States, with special focus on monoclonal antibodies used in the treatment of inflammatory diseases. METHODS: A search of the Internet as well as PubMed was conducted through June 2014 for information related to the clinical development of biosimilars using the keywords biosimilar, rheumatoid arthritis, juvenile idiopathic arthritis, psoriasis, psoriatic arthritis, Crohn's disease, ulcerative colitis, and ankylosing spondylitis. The European Medicines Agency (EMA) and the US Food and Drug Administration (FDA) websites were searched for biosimilar guidelines. RESULTS: The EMA began issuing draft guidelines for the development of biosimilars almost a decade ago and has approved numerous biosimilars. The US FDA has issued draft guidances providing stepwise considerations for the nonclinical and clinical development of biosimilars but has yet to approve a biosimilar under this pathway. CONCLUSIONS: Clinical trials aim to resolve uncertainties that may remain following nonclinical development regarding the similarity of the proposed biosimilar with the reference product. Pharmacokinetic and pharmacodynamic studies form the backbone of early clinical development and serve to inform phase 3 clinical development. Factors to be considered in clinical development include study population, design, end points, sample size, duration, and analytical methods.