Faculty Bibliography

We present a game theoretic framework that models strategic interactions among humans and things that are assumed to be interconnected by a social-technological network, as in an internet of humans and things (IOHT). Often a pair of agents in the network interacts in order for an informed sender-agent to signal an uninformed receiver-agent to take an action that benefits each of the players; the benefits to the pair of agents are modeled by two separate utility functions, both depending on the sender"™s private information, the signal exchanged, and the receiver"™s revealed (and also possibly unrevealed) action. In general, the two agents"™ utilities may not be aligned and may encourage deceptive behavior. For example, a sender, aware of his/her own private "state of ignorance", may seek useful information from a receiver who owns powerful computational resources to search a large corpus of webpages; the sender does so by sending a signal to the receiver in the form of a keyword. Obvious examples of deceptiveness here range from attempts to hide one"™s intentions to auctioning the keywords on an ad exchange through real-time bidding. A rather troublesome situation occurs when deceptions are employed to breach the security of the system, thus making the entire social-technological network unreliable. Earlier, we proposed a signaling-game-theoretic framework to alleviate this problem. This paper further enhances that framework by reconfiguring signals to possess more complex structures (epistatic signals to represent attack and defense options over a given set of vulnerabilities). We explore two augmentations to the original evolutionary signaling game by first enhancing mutation bias toward strategies performing well in previous populations and second allowing the parameters of the utility functions to depend on population preferences giving rise to a minority game with epistatic signaling. The resulting game systems are empirically studied through extensive computer simulation.

White adipose tissue (WAT) is essential for maintaining metabolic function, especially during obesity. The intronic microRNAs miR-33a and miR-33b, located within the genes encoding sterol-regulatory element-binding proteins, SREBP-2 and SREBP-1 respectively, are transcribed in concert with their host genes and function alongside them to regulate cholesterol, fatty acid, and glucose metabolism. SREBP-1 is highly expressed in mature WAT and plays a critical role in promoting in-vitro adipocyte differentiation. It is unknown whether miR-33b is induced during or involved in adipogenesis. This is in part due to loss of miR-33b in rodents, precluding in-vivo assessment of the impact of miR-33b using standard mouse models. This work demonstrates that miR-33b is highly induced upon differentiation of human pre-adipocytes, along with SREBP-1. We further report that miR-33b is an important regulator of adipogenesis, as inhibition of miR-33b enhanced lipid droplet accumulation. Conversely, overexpression of miR-33b impaired pre-adipocyte proliferation, and reduced lipid droplet formation and the induction of PPARgamma target genes during differentiation. These effects may be mediated by targeting of HMGA2, CDK6 and other predicted miR-33b targets. Together, these findings demonstrate a novel role of miR-33b in the regulation of adipocyte differentiation, with important implications for the development of obesity and metabolic disease.

Significance: Chronic wounds remain a significant public health problem. Alterations in normal physiological processes caused by aging or diabetes lead to impaired tissue repair and the development of chronic and nonhealing wounds. Understanding the unique features of the wound environment will be required to develop new therapeutics that impact these disabling conditions. New drug-delivery systems (DDSs) may enhance current and future therapies for this challenging clinical problem. Recent Advances: Historically, physical barriers and biological degradation limited the efficacy of DDSs in wound healing. In aiming at improving and optimizing drug delivery, recent data suggest that combinations of delivery mechanisms, such as hydrogels, small molecules, RNA interference (RNAi), as well as growth factor and stem cell-based therapies (biologics), could offer exciting new opportunities for improving tissue repair. Critical Issues: The lack of effective therapeutic approaches to combat the significant disability associated with chronic wounds has become an area of increasing clinical concern. However, the unique challenges of the wound environment have limited the development of effective therapeutic options for clinical use. Future Directions: New platforms presented in this review may provide clinicians and scientists with an improved understanding of the alternatives for drug delivery in wound care, which may facilitate the development of new therapeutic approaches for patients.

Formyl peptide receptor 1 (FPR1) targeting multimodal probe cFLFLFK-MHI-DOTA for leukocyte based inflammation imaging is described. The compound consists of three domains, (a) cFLFLF peptide for FPR1 recognition and binding for activated leukocyte, (b) heptamethine cyanine dye (MHI) for near infrared fluorescence (NIRF) detection and imaging, and (c) metal chelator DOTA ligand that could form complex with a radiometal for nuclear (PET/SPECT) imaging or with a paramagnetic metal for MRI imaging. Detailed synthesis, characterization and in vitro evaluation are reported. The availability of dual mode inflammation imaging probe would allow in vivo gross level imaging of inflammation foci as well as ex vivo microscopic level cellular imaging for role played by innate immune cells in inflamed tissue.

OBJECTIVES: Dalbavancin, a semi-synthetic lipoglycopeptide, is characterized by a long plasma half-life, which allows weekly dosing. Dalbavancin may be a good treatment option for patients with deep sternal wound infections owing to its improved pharmacokinetic profile and antibacterial activity compared with currently used antibiotics. Here we evaluated the efficacy of 7 or 14 days of treatment with dalbavancin, compared with vancomycin and with saline, in reducing sternal bone MRSA counts in a rat Staphylococcus aureus deep sternal wound infection model. METHODS: A mid-sternal wound was surgically induced in anaesthetized rats. A clinical strain of MRSA was injected into the sternum to establish infection. Rats were treated intraperitoneally for 7 or 14 days with dalbavancin, vancomycin or saline. The number of cfu per gram of sternum or spleen tissue was determined using viable counts. The antibacterial efficacy was determined by the reduction in bacterial counts per gram of sternum or spleen tissue in each treatment group. RESULTS: Treatment with dalbavancin was superior to treatment with saline for 7 days (0.75 log reduction in bone cfu) or 14 days (>3 log reduction in bone cfu) and similar to treatment with vancomycin. Additionally, dalbavancin was also effective in reducing systemic dissemination of MRSA. CONCLUSIONS: Dalbavancin is effective in the treatment of MRSA rat sternal osteomyelitis.

Connexin43 is the major component of gap junctions, an anatomical structure present in the cardiac intercalated disc that provides a low-resistance pathway for direct cell-to-cell passage of electrical charge. Recent studies have shown that in addition to its well-established function as an integral membrane protein that oligomerizes to form gap junctions, Cx43 plays other roles that are independent of channel (or perhaps even hemi-channel) formation. This article discusses non-canonical functions of Cx43. In particular, we focus on the role of Cx43 as a part of a protein interacting network, a connexome, where molecules classically defined as belonging to the mechanical junctions, the gap junctions and the sodium channel complex, multitask and work together to bring about excitability, electrical and mechanical coupling between cardiac cells. Overall, viewing Cx43 as a multi-functional protein, beyond gap junctions, opens a window to better understand the function of the intercalated disc and the pathological consequences that may result from changes in the abundance or localization of Cx43 in the intercalated disc subdomain.

: Human mesenchymal stem cells (MSCs) have recently become a focus of regenerative medicine, both for their multilineage differentiation capacity and their excretion of proregenerative cytokines. Adipose-derived mesenchymal stem cells (ASCs) are of particular interest because of their abundance in fat tissue and the ease of harvest via liposuction. However, little is known about the impact of different liposuction methods on the functionality of ASCs. Here we evaluate the regenerative abilities of ASCs harvested via a third-generation ultrasound-assisted liposuction (UAL) device versus ASCs obtained via standard suction-assisted lipoaspiration (SAL). Lipoaspirates were sorted using fluorescent assisted cell sorting based on an established surface-marker profile (CD34+/CD31-/CD45-), to obtain viable ASCs. Yield and viability were compared and the differentiation capacities of the ASCs were assessed. Finally, the regenerative potential of ASCs was examined using an in vivo model of tissue regeneration. UAL- and SAL-derived samples demonstrated equivalent ASC yield and viability, and UAL ASCs were not impaired in their osteogenic, adipogenic, or chondrogenic differentiation capacity. Equally, quantitative real-time polymerase chain reaction showed comparable expression of most osteogenic, adipogenic, and key regenerative genes between both ASC groups. Cutaneous regeneration and neovascularization were significantly enhanced in mice treated with ASCs obtained by either UAL or SAL compared with controls, but there were no significant differences in healing between cell-therapy groups. We conclude that UAL is a successful method of obtaining fully functional ASCs for regenerative medicine purposes. Cells harvested with this alternative approach to liposuction are suitable for cell therapy and tissue engineering applications. SIGNIFICANCE: Adipose-derived mesenchymal stem cells (ASCs) are an appealing source of therapeutic progenitor cells because of their multipotency, diverse cytokine profile, and ease of harvest via liposuction. Alternative approaches to classical suction-assisted liposuction are gaining popularity; however, little evidence exists regarding the impact of different liposuction methods on the regenerative functionality of ASCs. Human ASC characteristics and regenerative capacity were assessed when harvested via ultrasound-assisted (UAL) versus standard suction-assisted liposuction. ASCs obtained via UAL were of equal quality when directly compared with the current gold standard harvest method. UAL is an adjunctive source of fully functional mesenchymal stem cells for applications in basic research and clinical therapy.

The eukaryotic translation initiation factor 2alpha (eIF2alpha) phosphorylation-dependent integrated stress response (ISR), a component of the unfolded protein response, has long been known to regulate intermediary metabolism, but the details are poorly worked out. We report that profiling of mRNAs of transgenic mice harboring a ligand-activated skeletal muscle-specific derivative of the eIF2alpha protein kinase R-like ER kinase revealed the expected up-regulation of genes involved in amino acid biosynthesis and transport but also uncovered the induced expression and secretion of a myokine, fibroblast growth factor 21 (FGF21), that stimulates energy consumption and prevents obesity. The link between the ISR and FGF21 expression was further reinforced by the identification of a small-molecule ISR activator that promoted Fgf21 expression in cell-based screens and by implication of the ISR-inducible activating transcription factor 4 in the process. Our findings establish that eIF2alpha phosphorylation regulates not only cell-autonomous proteostasis and amino acid metabolism, but also affects non-cell-autonomous metabolic regulation by induced expression of a potent myokine.-Miyake, M., Nomura, A., Ogura, A., Takehana, K., Kitahara, Y., Takahara, K., Tsugawa, K., Miyamoto, C., Miura, N., Sato, R., Kurahashi, K., Harding, H. P., Oyadomari, M., Ron, D., Oyadomari, S. Skeletal muscle-specific eukaryotic translation initiation factor 2alpha phosphorylation controls amino acid metabolism and fibroblast growth factor 21-mediated non-cell-autonomous energy metabolism.

BACKGROUND: Systemic antibiotics are used widely to treat moderate to severe acne, but increasing antibiotic resistance makes appropriate use a priority. OBJECTIVE: We sought to determine the duration of systemic antibiotic use in patients with inflammatory/nodulocystic acne who eventually required isotretinoin. METHODS: We performed a retrospective, single-site chart review of patients with acne diagnostic codes evaluated January 1, 2005 to December 31, 2014, at a dermatology practice in an academic medical center. Included patients were prescribed isotretinoin during the study period and received 30 days or more of antibiotics. RESULTS: The average duration of antibiotic use was 331.3 days. In all, 21 patients (15.3%) were prescribed antibiotics for 3 months or less, 88 patients (64.2%) for 6 months or more, and 46 patients (33.6%) for 1 year or longer. Patients treated only at the study site had a mean duration of antibiotic treatment of 283.1 days whereas patients who also received antibiotics from another institution had a mean duration of 380.2 days. This difference approached statistical significance (P = .054). LIMITATIONS: This study was limited to a single center. CONCLUSION: Expert guidelines recommend responsible use of antibiotics in acne in light of emerging resistance. We found that patients who eventually received isotretinoin had extended exposure to antibiotics, exceeding recommendations. Early recognition of antibiotic failure and the need for isotretinoin can curtail antibiotic use.

Adipose-derived mesenchymal stem cells (ASCs) are appealing for cell-based wound therapies because of their accessibility and ease of harvest, but their utility is limited by poor cell survival within the harsh wound microenvironment. In prior work, our laboratory has demonstrated that seeding ASCs within a soft pullulan-collagen hydrogel enhances ASC survival and improves wound healing. To more fully understand the mechanism of this therapy, we examined whether ASC-seeded hydrogels were able to modulate the recruitment and/or functionality of endogenous progenitor cells. Employing a parabiosis model and fluorescence-activated cell sorting analysis, we demonstrate that application of ASC-seeded hydrogels to wounds, when compared with injected ASCs or a noncell control, increased the recruitment of provascular circulating bone marrow-derived mesenchymal progenitor cells (BM-MPCs). BM-MPCs comprised 23.0% of recruited circulating progenitor cells in wounds treated with ASC-seeded hydrogels versus 8.4% and 2.1% in those treated with controls, p < 0.05. Exploring the potential for functional modulation of BM-MPCs, we demonstrate a statistically significant increase in BM-MPC migration, proliferation, and tubulization when exposed to hydrogel-seeded ASC-conditioned medium versus control ASC-conditioned medium (73.8% vs. 51.4% scratch assay closure; 9.1% vs. 1.4% proliferation rate; 10.2 vs. 5.5 tubules/HPF; p < 0.05 for all assays). BM-MPC expression of genes related to cell stemness and angiogenesis was also significantly increased following exposure to hydrogel-seeded ASC-conditioned medium (p < 0.05). These data suggest that ASC-seeded hydrogels improve both progenitor cell recruitment and functionality to effect greater neovascularization.