Faculty Bibliography

BACKGROUND: A core responsibility of medical educators is to foster a strong sense of medical professional identity (PI). Few studies specifically examine the qualities that constitute the PI of physicians recognized for exemplary professionalism. We describe those qualities based on an assessment of PI to inform educational efforts and support learners' development of PI.
METHOD(S): We used Colby and Damon's criteria for selection of moral exemplars (1992) to invite nominations of exemplary faculty physicians at NYUGSOM from faculty and trainees. Participants completed the Professional Identity Essay (PIE), a 9-question reflective writing measure based on a wellknown model of adult development that explores meaning making on PI (Bebeau & Lewis, 2004; Kegan, 1982, 1994). Two raters with extensive training and experience in adult developmental theory rated PIE responses for stage or transition phase. PI stages include independent operator, teamoriented idealist, self-defining, and self-transforming. These stages reflect increasing complexity and internalization of PI. We also gathered information on specialty, years in practice, gender, and race/ethnicity.
RESULT(S): Two hundred and twelve faculty were nominated; 35 were invited to participate (based on number of nominations, diversity of ages, backgrounds and career stage), and 21 completed scorable PIEs. They were from 13 specialties; mean career length was 21.5 years (range 6-45), and 35% were female. All but 2 were Caucasian. PIE scores ranged from 3 to 4.5 (Table 1), demonstrating differing and increasingly complex and internalized ways faculty understand their PI, and that not all nominated exemplars share a singular view of professionalism.
CONCLUSION(S): Physicians nominated as exemplars of professionalism embody a range of professional identities and professionalism world-views. Our study provides rich descriptions of multiple pathways to strengthening a physician's professionalidentities, of critical importance to faculty and physician development in a milieu of challenges to recruitment and retention of physicians. This approach can also inform educators' efforts to support PI development in learners and support the development of learning communities that foster a growth mindset. LEARNING OBJECTIVE #1: Recognize importance of strong role models for MPI. LEARNING OBJECTIVE #2: Describe the varying levels of MPI in a cohort of exemplar physicians

To investigate the effects and mechanisms of irisin, a newly discovered myokine, in cartilage development, osteoarthritis (OA) pathophysiology and its therapeutic potential for treating OA we applied the following five strategical analyses using (1) murine joint tissues at different developmental stages; (2) human normal and OA pathological tissue samples; (3) experimental OA mouse model; (4) irisin gene knockout (KO) and knock in (KI) mouse lines and their cartilage cells; (5) in vitro mechanistic experiments. We found that Irisin was involved in all stages of cartilage development. Both human and mouse OA tissues showed a decreased expression of irisin. Intra-articular injection of irisin attenuated ACLT-induced OA progression. Irisin knockout mice developed severe OA while irisin overexpression in both irisin KI mice and intraarticular injection of irisin protein attenuated OA progression. Irisin inhibited inflammation and promoted anabolism in chondrogenic ADTC5 cells. Proliferative potential of primary chondrocytes from KI mice was found to be enhanced, while KO mice showed an inhibition under normal or inflammatory conditions. The primary chondrocytes from irisin KI mice showed reduced expression of inflammatory factors and the chondrocytes isolated from KO mice showed an opposite pattern. In conclusion, it is the first time to show that irisin is involved in cartilage development and OA pathogenesis. Irisin has the potential to ameliorate OA progression by decreasing cartilage degradation and inhibiting inflammation, which could lead to the development of a novel therapeutic target for treating bone and cartilage disorders including osteoarthritis.

The NF-κβ transcription factor is a molecular mediator crucial to many biological functions and a central regulator of inflammatory and immune responses. NF-κβ is activated by multiple immunologically relevant stimuli, including members of the tumor necrosis factor (TNF) superfamily, and targeting TNF/NFκβ activity is a therapeutic objective in many inflammatory and autoimmune conditions. Here, we describe the generation of a transgenic reporter mouse model, expressing the human tumor necrosis factor α (TNF-α) transgene (TNF-tg) and carrying the luciferase gene under control of the NFκB-responsive element (NF-κB-Luc). Bioluminescence imaging shows that overexpression of TNF-α effectively activates NF-κB luciferase in vivo. To evaluate this system as a screen for potential therapeutics targeting the TNF/NFκβ signaling pathway, we treated double mutant mice with PGRN-derived Atsttrin, an engineered molecule comprising the minimal progranulin (PGRN):TNFR binding fragments previously demonstrated as therapeutic in multiple models of TNF/NFκβ-driven disease. Administration of Atsttrin could effectively inhibit luciferase activity in TNF-tg:NF-κB-Luc double mutant mice and demonstrates that this transgenic model can be used to non-invasively monitor the in vivo efficacy of modulators of TNF-activated NF-κB signaling pathway.

Gap junctions are molecular structures that allow communication between neighboring cells. It has been shown that gap junctional intercellular communication (GJIC) is notoriously reduced in cancer cells compared to their normal counterparts. Ouabain, a plant derived substance, widely known for its therapeutic properties on the heart, has been shown to play a role in several types of cancer, although its mechanism of action is not yet fully understood. Since we have previously shown that ouabain enhances GJIC in epithelial cells (MDCK), here we probed whether ouabain affects GJIC in a variety of cancer cell lines, including cervico-uterine (CasKi, SiHa and Hela), breast (MDA-MB-321 and MCF7), lung (A549), colon (SW480) and pancreas (HPAF-II). For this purpose, we conducted dye transfer assays to measure and compare GJIC in monolayers of cells with and without treatment with ouabain (0.1, 1, 10, 50 and 500 nM). We found that ouabain induces a statistically significant enhancement of GJIC in all of these cancer cell lines, albeit with distinct sensitivity. Additionally, we show that synthesis of new nucleotides or protein subunits is not required, and that Csrc, ErK1/2 and ROCK-Rho mediate the signaling mechanisms. These results may contribute to explaining how ouabain influences cancer.

Type I and III interferons induce expression of the "myxovirus resistance proteins" MxA in human cells and its ortholog Mx1 in murine cells. Human MxA forms cytoplasmic structures, whereas murine Mx1 forms nuclear bodies. Whereas both HuMxA and MuMx1 are antiviral toward influenza A virus (FLUAV) (an orthomyxovirus), only HuMxA is considered antiviral toward vesicular stomatitis virus (VSV) (a rhabdovirus). We previously reported that the cytoplasmic human GFP-MxA structures were phase-separated membraneless organelles ("biomolecular condensates"). In the present study, we investigated whether nuclear murine Mx1 structures might also represent phase-separated biomolecular condensates. The transient expression of murine GFP-Mx1 in human Huh7 hepatoma, human Mich-2H6 melanoma, and murine NIH 3T3 cells led to the appearance of Mx1 nuclear bodies. These GFP-MuMx1 nuclear bodies were rapidly disassembled by exposing cells to 1,6-hexanediol (5%, w/v), or to hypotonic buffer (40-50 mosm), consistent with properties of membraneless phase-separated condensates. Fluorescence recovery after photobleaching (FRAP) assays revealed that the GFP-MuMx1 nuclear bodies upon photobleaching showed a slow partial recovery (mobile fraction: ∼18%) suggestive of a gel-like consistency. Surprisingly, expression of GFP-MuMx1 in Huh7 cells also led to the appearance of GFP-MuMx1 in 20-30% of transfected cells in a novel cytoplasmic giantin-based intermediate filament meshwork and in cytoplasmic bodies. Remarkably, Huh7 cells with cytoplasmic murine GFP-MuMx1 filaments, but not those with only nuclear bodies, showed antiviral activity toward VSV. Thus, GFP-MuMx1 nuclear bodies comprised phase-separated condensates. Unexpectedly, GFP-MuMx1 in Huh7 cells also associated with cytoplasmic giantin-based intermediate filaments, and such cells showed antiviral activity toward VSV.

Bone morphogenetic protein-9 (BMP-9) is a circulating cytokine that is known to play an essential role in the endothelial homeostasis and the binding of BMP-9 to the receptor activin-like kinase 1 (ALK-1) promotes endothelial cell quiescence. Previously, using an unbiased screen, we identified ALK-1 as a high-capacity receptor for low-density lipoprotein (LDL) in endothelial cells that mediates its transcytosis in a nondegradative manner. Here we examine the crosstalk between BMP-9 and LDL and how it influences their interactions with ALK-1. Treatment of endothelial cells with BMP-9 triggers the extensive endocytosis of ALK-1, and it is mediated by caveolin-1 (CAV-1) and dynamin-2 (DNM2) but not clathrin heavy chain. Knockdown of CAV-1 reduces BMP-9-mediated internalization of ALK-1, BMP-9-dependent signaling and gene expression. Similarly, treatment of endothelial cells with LDL reduces BMP-9-induced SMAD1/5 phosphorylation and gene expression and silencing of CAV-1 and DNM2 diminishes LDL-mediated ALK-1 internalization. Interestingly, BMP-9-mediated ALK-1 internalization strongly re-duces LDL transcytosis to levels seen with ALK-1 deficiency. Thus, BMP-9 levels can control cell surface levels of ALK-1, via CAV-1, to regulate both BMP-9 signaling and LDL transcytosis.

Metallothioneins (MTs) are a diverse group of proteins responsible for the control of metal homeostasis and detoxification. To investigate the impact that environmental conditions might have had on the metal-binding abilities of these proteins, we have characterized the MTs from the apple snail Pomacea bridgesii, a gastropod species belonging to the class of Caenogastropoda with an amphibious lifestyle facing diverse situations of metal bioavailability. P. bridgesii has two structurally divergent MTs, named PbrMT1 and PbrMT2, that are longer than other gastropod MTs due to the presence of extra sequence motifs and metal-binding domains. We have characterized the Zn(II), Cd(II), and Cu(I) binding abilities of these two MTs after their heterologous expression in E. coli. Our results have revealed that despite their structural differences, both MTs share an unspecific metal-binding character, and a great ability to cope with elevated amounts of different metal ions. Our analyses have also revealed slight divergences in their metal-binding features: PbrMT1 shows a more pronounced Zn(II)-thionein character than PbrMT2, while the latter has a stronger Cu(I)-thionein character. The characterization of these two unconventional PbrMTs supports the loss of the metal-binding specificity during the evolution of the MTs of the Ampullariid family, and further suggests an evolutionary link of this loss with the adaptation of these gastropod lineages to metal-poor freshwater habitats.