Faculty Bibliography

Stem cells are attractive candidates for the development of novel therapies, targeting indications that involve functional restoration of defective tissue. Although most stem cell therapies are new and highly experimental, there are clinics around the world that exploit vulnerable patients with the hope of offering supposed stem cell therapies, many of which operate without credible scientific merit, oversight, or other patient protection.We review the potential, as well as drawbacks, for incorporation of stem cells in cosmetic procedures. A review of FDA-approved indications and ongoing clinical trials with adipose stem cells is provided. Furthermore, a "snapshot" analysis of websites using the search terms "stem cell therapy" or "stem cell treatment" or "stem cell facelift" was performed.Despite the protective net cast by regulatory agencies such as the FDA and professional societies such as the American Society of Plastic Surgeons, we are witnessing worrying advertisements for procedures such as stem cell facelifts, stem cell breast augmentations, and even stem cell vaginal rejuvenation. The marketing and promotion of stem cell procedures in aesthetic surgery is not adequately supported by clinical evidence in the majority of cases.Stem cells offer tremendous potential, but the marketplace is saturated with unsubstantiated and sometimes fraudulent claims that may place patients at risk. With plastic surgeons at the forefront of stem cell-based regenerative medicine, it is critically important that we provide an example of a rigorous approach to research, data collection, and advertising of stem cell therapies.

The Unfolded Protein Response of the endoplasmic reticulum (UPRER) controls proteostasis by adjusting the protein folding capacity of the ER to environmental and cell-intrinsic conditions. In metazoans, loss of proteostasis results in degenerative and proliferative diseases and cancers. The cellular and molecular mechanisms causing these phenotypes remain poorly understood. Here we show that the UPRER is a critical regulator of intestinal stem cell (ISC) quiescence in Drosophila melanogaster. We find that ISCs require activation of the UPRER for regenerative responses, but that a tissue-wide increase in ER stress triggers ISC hyperproliferation and epithelial dysplasia in aging animals. These effects are mediated by ISC-specific redox signaling through Jun-N-terminal Kinase (JNK) and the transcription factor CncC. Our results identify a signaling network of proteostatic and oxidative stress responses that regulates ISC function and regenerative homeostasis in the intestinal epithelium.

OBJECTIVE: To examine the expression of ADAMTS-7 during the progression of osteoarthritis (OA), defining its role in the pathogenesis of OA, and elucidating the molecular events involved. METHODS: ADAMTS-7 expression in cartilage of a rat OA model was assayed using immunohistochemistry. Cartilage-specific ADAMTS-7 transgenic mice and ADAMTS-7 small interfering (si)RNA knockdown mice were generated and used to analyse OA progression in both spontaneous and surgically induced OA models. Cartilage degradation and OA was evaluated using Safranin-O staining, immunohistochemistry, ELISA and western blotting. In addition, mRNA expression of tumour necrosis factor (TNF)-alpha and metalloproteinases known to be involved in cartilage degeneration in OA was analysed. Furthermore, the transactivation of ADAMTS-7 by TNF-alpha and its downstream NF-kappaB signalling was measured using reporter gene assay. RESULTS: ADAMTS-7 expression was elevated during disease progression in the surgically induced rat OA model. Targeted overexpression of ADAMTS-7 in chondrocytes led to chondrodysplasia characterised by short-limbed dwarfism and a delay in endochondral ossification in 'young mice' and a spontaneous OA-like phenotype in 'aged' mice. In addition, overexpression of ADAMTS-7 led to exaggerated breakdown of cartilage and accelerated OA progression, while knockdown of ADAMTS-7 attenuated degradation of cartilage matrix and protected against OA development, in surgically induced OA models. ADAMTS-7 upregulated TNF-alpha and metalloproteinases associated with OA; in addition, TNF-alpha induced ADAMTS-7 through NF-kappaB signalling. CONCLUSIONS: ADAMTS-7 and TNF-alpha form a positive feedback loop in the regulation of cartilage degradation and OA progression, making them potential molecular targets for prevention and treatment of joint degenerative diseases, including OA.

BACKGROUND: & Aims: Subsets of leukocytes synergize with regenerative growth factors to promote hepatic regeneration. gammadeltaTau cells are early responders to inflammation-induced injury in a number of contexts. We investigated the role of gammadeltaTau cells in hepatic regeneration using mice with disruptions in Tcrd (encodes the T cell receptor delta chain) and Clec7a (encodes C-type lectin domain family 7 member a, also known as DECTIN1). METHODS: We performed partial hepatectomies on wild-type C57BL/6, CD45.1, Tcrd-/-, or Clec7a-/- mice. Cells were isolated from livers of patients and mice via mechanical and enzymatic digestion. gammadeltaTau cells were purified by fluorescence-activated cell sorting. RESULTS: In mice, partial hepatectomy upregulated expression of CCL20 and ligands of Dectin-1, associated with recruitment and activation of gammadeltaTau cells and their increased production of interleukin (IL)17 family cytokines. Recruited gammadeltaTau cells induced production of IL6 by antigen-presenting cells and suppressed expression of interferon gamma by natural killer T cells, promoting hepatocyte proliferation. Absence of IL17-producing gammadeltaTau cells or deletion of Dectin-1 prevented development of regenerative phenotypes in subsets of innate immune cells. This slowed liver regeneration and was associated with reduced expression of regenerative growth factors and cell cycle regulators. Conversely, exogenous administration of IL17 family cytokines or Dectin-1 ligands promoted regeneration. More broadly, we found that gammadeltaTau cells are required for inflammatory responses mediated by IL17 and Dectin-1. CONCLUSIONS: gammadeltaT cells regulate hepatic regeneration by producing IL22 and IL17, which have direct mitogenic effects on hepatocytes and promote a regenerative phenotype in hepatic leukocytes, respectively. Dectin-1 ligation is required for gammadeltaT cells to promote hepatic regeneration.

PURPOSE OF REVIEW: The objective of this review article is to summarize the recent findings about the importance of microRNAs (miRNAs) in regulating lipoprotein metabolism. We highlight the recent findings that uncover the importance of miRNAs in controlling plasma LDL-cholesterol (LDL-C) levels. RECENT FINDINGS: In 2013, several studies reported a number of miRNAs that regulate plasma LDL-C levels, including miR-30c. In this review article, we discuss those miRNAs that modulate LDL-C levels and lipoprotein secretion. We also discuss the numerous studies that demonstrate the critical role of miRNAs in governing the many facets of HDL metabolism, such as the ATP transporters, ABCA1, and ABCG1, and the scavenger receptor, SRB1. SUMMARY: The understanding of how these miRNAs modulate lipoprotein metabolism promises to reveal new therapeutic targets to treat dyslipidemias and related cardiovascular disorders.

Most multicellular organisms show a physiological decline in immune function with age. However, little is known about the mechanisms underlying these changes. We examined Drosophila melanogaster, an important model for identifying genes affecting innate immunity and senescence, to explore the role of phagocytosis in age-related immune dysfunction. We characterized the localized response of immune cells at the dorsal vessel to bacterial infection in 1-week- and 5-week-old flies. We developed a quantitative phagocytosis assay for adult Drosophila and utilized this to characterize the effect of age on phagocytosis in transgenic and natural variant lines. We showed that genes necessary for bacterial engulfment in other contexts are also required in adult flies. We found that blood cells from young and old flies initially engulf bacteria equally well, while cells from older flies accumulate phagocytic vesicles and thus are less capable of destroying pathogens. Our results have broad implications for understanding how the breakdown in cellular processes influences immune function with age.

BACKGROUND: Parkinson's disease (PD) is the second most common neurodegenerative movement disorder, caused by preferential dopaminergic neuronal cell death in the substantia nigra, a process also influenced by oxidative stress. L-3,4-dihydroxyphenylalanine (L-DOPA) represents the main treatment route for motor symptoms associated with PD however, its exact mode of action remains unclear. A spectrum of conflicting data suggests that L-DOPA may damage dopaminergic neurons due to oxidative stress whilst other data suggest that L-DOPA itself may induce low levels of oxidative stress, which in turn stimulates endogenous antioxidant mechanisms and neuroprotection. RESULTS: In this study we performed a two-dimensional gel electrophoresis (2DE)-based proteomic study to gain further insight into the mechanism by which L-DOPA can influence the toxic effects of H2O2 in neuronal cells. We observed that oxidative stress affects metabolic pathways as well as cytoskeletal integrity and that neuronal cells respond to oxidative conditions by enhancing numerous survival pathways. Our study underlines the complex nature of L-DOPA in PD and sheds light on the interplay between oxidative stress and L-DOPA. CONCLUSIONS: Oxidative stress changes neuronal metabolic routes and affects cytoskeletal integrity. Further, L-DOPA appears to reverse some H2O2-mediated effects evident at both the proteome and cellular level.

Although the principles that balance stem cell self-renewal and differentiation in normal tissue homeostasis are beginning to emerge, it is still unclear whether cancer cells with tumour initiating potential are similarly governed, or whether they have acquired distinct mechanisms to sustain self-renewal and long-term tumour growth. Here we show that the transcription factor Sox2, which is not expressed in normal skin epithelium and is dispensable for epidermal homeostasis, marks tumour initiating cells (TICs) in cutaneous squamous cell carcinomas (SCCs). We demonstrate that Sox2 is required for SCC growth in mouse and human, where it enhances Nrp1/Vegf signalling to promote the expansion of TICs along the tumour-stroma interface. Our findings suggest that distinct transcriptional programmes govern self-renewal and long-term growth of TICs and normal skin epithelial stem and progenitor cells. These programmes present promising diagnostic markers and targets for cancer-specific therapies.

BACKGROUND:During early brain development, the organisation of neural progenitors into a neuroepithelial sheet maintains tissue integrity during growth. Neuroepithelial cohesion and patterning is essential for orderly proliferation and neural fate specification. Neuroepithelia are regionalised by the expression of transcription factors and signalling molecules, resulting in the formation of distinct developmental, and ultimately functional, domains. RESULTS:We have discovered that the Six3/6 family orthologue Optix is an essential regulator of neuroepithelial maintenance and patterning in the Drosophila brain. Six3 and Six6 are required for mammalian eye and forebrain development, and mutations in humans are associated with severe eye and brain malformation. In Drosophila, Optix is expressed in a sharply defined region of the larval optic lobe, and its expression is reciprocal to that of the transcription factor Vsx1. Optix gain- and loss-of-function affects neuroepithelial adhesion, integrity and polarity. We find restricted cell lineage boundaries that correspond to transcription factor expression domains. CONCLUSION/CONCLUSIONS:We propose that the optic lobe is compartmentalised by expression of Optix and Vsx1. Our findings provide insight into the spatial patterning of a complex region of the brain, and suggest an evolutionarily conserved principle of visual system development.