After peripheral nerve injury, neurotrophins play a key role in the regeneration of damaged axons which can be augmented by exercise, although the distinct roles played by neurons and Schwann cells are unclear. In this study, we evaluated the requirement for the neurotrophin, brain derived neurotrophic factor (BDNF), in neurons and Schwann cells, for the regeneration of peripheral axons after injury. Common fibular or tibial nerves in thy-1-YFP-H mice were cut bilaterally and repaired using a graft of the same nerve from transgenic mice lacking BDNF in Schwann cells (BDNF-/-) or wild-type mice (WT). Two weeks post-repair, axonal regeneration into BDNF-/- grafts were markedly less than WT grafts, emphasizing the importance of Schwann cell BDNF. Nerve regeneration was enhanced by treadmill training post-transection, regardless of the BDNF content of the nerve graft. We further tested the hypothesis that training-induced increases in BDNF in neurons allow regenerating axons to overcome a lack of BDNF expression in cells in the pathway through which they regenerate. Nerves in mice lacking BDNF in YFP+ neurons (SLICK) were cut and repaired with BDNF-/- and WT nerves. SLICK axons lacking BDNF did not regenerate into grafts lacking Schwann cell BDNF. Treadmill training could not rescue the regeneration into BDNF-/- grafts if the neurons also lacked BDNF. Both Schwann cell- and neuron-derived BDNF are thus important for axon regeneration in cut peripheral nerves.

Injury‐related, post‐traumatic osteoarthritis (PTOA) is a disease of the joints caused by an imbalance between extracellular matrix destruction and production. We have developed an innovative disease modifying therapeutic technology to treat PTOA. Extracellular matrix protection factor (ECPF‐1) is a novel, safe and effective intra‐articular injection that reduces the pain and damage caused by OA. Utilizing the peptide as an early intervention therapeutic, we have assessed its effects on the progression of PTOA. Peptide or control saline was injected into the injured knee joint for four consecutive weeks. Endpoint assessment of: toxicity, measured by CBC and serum chemistry; joint space narrowing, measured by Xray; joint functionality, measured by stride test; and tissue pathology, measured by micro computed tomography and histology were completed. Intra‐articular injections of ECPF‐1 in a rat model of PTOA demonstrated no cellular toxicity, normal serum chemistry following 4 weekly injections, diminished tissue destruction and increased animal mobility. All data indicates that ECPF‐1 is non‐toxic and diminishes the pathology associated with OA. Grant Funding Source: Supported by intramural funds

Articular cartilage damage leads to osteoarthritis (OA), a disease characterized by altered cartilage homeostasis. Several cellular elements including growth factors and proteases are involved in this pathology. Our lab has developed a new class of therapeutic, extracellular matrix protection factors (ECPFs), that protect cartilage from the devastation associated with OA. ECPF‐1 targets the interaction between matrix metalloprotease 13 (MMP‐13) and transforming growth factor β (TGF‐β), but the cellular mechanism of ECPF‐1 chondroprotection is unknown. Inflammatory cytokines play a role in the pathology associated with OA, and are regulated, in some part, by TGF‐β biology. To test the downstream effects of blocking TGF‐β activation on cytokine production, cultured chondrocytes from embryonic avian sterna were treated for 24 hours with ECPF‐1 at 250nM, 2.5μM and 5.0μM concentrations and the production of the inflammatory cytokines, IL‐1β and TNF‐α, were monitored. Activated TGF‐β was reduced and production of IL‐1β and TNF‐α were decreased in response to ECPF‐1 treatment including an unexpected increase in these cytokines following 5.0μM addition of ECPF‐1. This biphasic effect of ECPF‐1 indicates a duality to the protective therapeutic nature and overall mechanism of action of ECPF‐1 in the protection of articular cartilage.

Insulin‐like growth factor‐II (IGF‐II) mRNA‐binding protein‐2 (IMP2) is one of the three homologs (IMP1–3) that play important roles in the posttranscriptional regulation of gene expression in several tissues. IMP1/ZBP1 (zipcode binding protein) has been shown to play important roles in axon guidance and regeneration by regulating the localization and translation of specific mRNAs. However, the function of IMP2 is least understood, largely because an isoform‐specific antibody is not available, which makes the conventional techniques to locate protein expression not feasible. We custom made an IMP2‐specific antibody. We used Western blot and immunocytochemistry to test its specificity on cultured cells following over expression of IMP 1–3 isoforms, respectively. Using this IMP2‐specific antibody, we examined IMP2 expression in the mouse nervous system. We found that IMP2 expression in the nervous system is sustained postnatally, unlike that of IMP1 and IMP3. Ongoing experiments are aimed at further understanding IMP2 expression patterns during injury and assessment of its role to facilitate mRNA localization during axon regeneration in the adult nervous system.This work is supported by the Department of Anatomy, PCOM and Center for Chronic Disorders of Aging (CCDA).

Clinical use of stem cells provide undeniable advantages as they can substitute for injured cells, tissues, and even organs in the human body. Adult adipose‐derived stem cells (ADSCs), have vast potential for clinical medicine because they can easily be harvested from a patient and provide an autologous transplant option. Data gathered in our lab has shown that harvesting ADSCs using water‐jet assisted liposuction (BodyJet) with laser‐assisted lipoplasty (SmartLipo) techniques produces a high yield of viable stem cells. These isolated cells can be plated in monolayer culture and retain their stem cell phenotype. In this study, we test the differentiation abilities of these BodyJet/SmartLipo harvested cells following cryopreservation. Since the clinical use of ADSCs is highly indicated for orthopedic and arthritis applications, we tested the ability of the liposuction‐harvested ADSCs to differentiate along the chondrocyte and osteoblast lineages. In this study, we compare the cryopreserved primary human ADSCs to a normal human, mesenchymal ADSC line, to measure stem cell viability and differentiation following thaw. Utilizing confocal microscopy, real‐time PCR, cell counts, alizarin red and alcian blue staining, the stem cells show promise in their ability to differentiate along the chondrocyte and osteoblast lineages. These data support the clinically‐relevant idea that lipoplasty‐obtained ADSCs will retain multipotency. Grant Funding Source: Supported by Pennsylvania Department of Health