Tetravalent Immunogen Assembled from Conserved Regions of HIV-1 and Delivered as mRNA Demonstrates Potent Preclinical T-Cell Immunogenicity and Breadth.

A vaccine will likely be one of the key tools for ending the HIV-1/AIDS epidemic by preventing HIV-1 spread within uninfected populations and achieving a cure for people living with HIV-1. The currently prevailing view of the vaccine field is to introduce protective antibodies, nevertheless, a vaccine to be effective may need to harness protective T cells. We postulated that focusing a T-cell response on the most vulnerable regions of the HIV-1 proteome while maximizing a perfect match between the vaccine and circulating viruses will control HIV-1 replication. We currently use a combination of replication-deficient simian (chimpanzee) adenovirus and poxvirus modified vaccinia virus Ankara to deliver bivalent conserved-mosaic immunogens to human volunteers. Here, we exploit the mRNA platform by designing tetravalent immunogens designated as HIVconsvM, and demonstrate that mRNA formulated in lipid nanoparticles induces potent, broad and polyfunctional T-cell responses in a pre-clinical model. These results support optimization and further development of this vaccine strategy in experimental medicine trials in humans.

The stories they tell: How third year medical students portray patients, family members, physicians, and themselves in difficult encounters.

BACKGROUND: Physicians have long had patients whom they have labeled "difficult", but little is known about how medical students perceive difficult encounters with patients. METHODS: In this study, we analyzed 134 third year medical students' reflective essays written over an 18-month period about difficult student-patient encounters. We used a qualitative computerized software program, Atlas.ti to analyze students' observations and reflections. RESULTS: Main findings include that students described patients who were angry and upset; noncompliant with treatment plans; discussed "nonmedical" problems; fearful, worried, withdrawn, or "disinterested" in their health. Students often described themselves as anxious, uncertain, confused, and frustrated. Nevertheless, they saw themselves behaving in empathic and patient-centered ways while also taking refuge in "standard" behaviors not necessarily appropriate to the circumstances. Students rarely mentioned receiving guidance from attendings regarding how to manage these challenging interactions. CONCLUSIONS: These third-year medical students recognized the importance of behaving empathically in difficult situations and often did so. However, they often felt overwhelmed and frustrated, resorting to more reductive behaviors that did not match the needs of the patient. Students need more guidance from attending physicians in order to approach difficult interactions with specific problem-solving skills while maintaining an empathic, patient-centered context.

Surrogate insulin-producing cells.

Diabetes, a large and growing worldwide health concern, affects the functional mass of the pancreatic beta cell, which in turn affects the glucose regulation of the body. Successful transplantation of cadaveric islets and pancreata for patients with uncontrolled type 1 diabetes has provided proof-of-concept for the development of commercial cell therapy approaches to treat diabetes. Three broad issues must be addressed before surrogate insulin-producing cells can become a reality: the development of a surrogate beta-cell source, immunoprotection, and translation. Cell therapy for diabetes is a real possibility, but many questions remain; through the collaborative efforts of multiple stakeholders this may become a reality.

New ISSCR guidelines underscore major principles for responsible translational stem cell research.

The International Society for Stem Cell Research (ISSCR) task force that developed new Guidelines for the Clinical Translation of Stem Cells discusses core principles that should guide the responsible transition of basic stem cell research into appropriate clinical applications.

Phosphotyrosine 1062 is critical for the in vivo activity of the Ret9 receptor tyrosine kinase isoform.

The receptor tyrosine kinase Ret plays a critical role in the development of the mammalian excretory and enteric nervous systems. Differential splicing of the primary Ret transcript results in the generation of two main isoforms, Ret9 and Ret51, whose C-terminal amino acid tails diverge after tyrosine (Y) 1062. Monoisoformic mice expressing only Ret9 develop normally and are healthy and fertile. In contrast, animals expressing only Ret51 have aganglionosis of the distal gut and hypoplastic kidneys. By generating monoisoformic mice in which Y1062 of Ret9 has been mutated to phenylalanine, we demonstrate that this amino acid has a critical role in Ret9 signaling that is necessary for the development of the kidneys and the enteric nervous system. These findings argue that the distinct activities of Ret9 and Ret51 result from the differential regulation of Y1062 by C-terminal flanking sequences. However, a mutation which places Y1062 of Ret51 in a Ret9 context improves only marginally the ability of Ret51 to support renal and enteric nervous system development. Finally, monoisoformic mice expressing a variant of Ret9 in which a C-terminal PDZ-binding motif was mutated develop normally and are healthy. Our studies identify Y1062 as a critical regulator of Ret9 signaling and suggest that Ret51-specific motifs are likely to inhibit the activity of this isoform.

Functional significance of Tie2 signaling in the adult vasculature.

Abundant data now demonstrate that the growth of new blood vessels, termed angiogenesis, plays both pathological and beneficial roles in human disease. Based on these data, a tremendous effort has been undertaken to understand the molecular mechanisms that drive blood vessel growth in adult tissues. Tie2 recently was identified as a receptor tyrosine kinase expressed principally on vascular endothelium. Disrupting Tie2 function in mice resulted in embryonic lethality with defects in embryonic vasculature, suggesting a role in blood vessel maturation and maintenance. Based on these studies, we undertook a series of studies to probe the function of Tie2 in adult vasculature that will form the focus of this chapter. Consistent with a role in blood vessel growth in adult vasculature, Tie2 was upregulated and activated in the endothelium of rat ovary and in healing rat skin wounds, both areas of active angiogenesis. Moreover, Tie2 was upregulated in the endothelium of vascular "hot spots" in human breast cancer specimens. Surprisingly, Tie2 also was expressed and activated in the endothelium of all normal rat tissues examined, suggesting a role in maintenance of adult vasculature. To determine the functional role of Tie2 in tumor vasculature, a soluble Tie2 extracellular domain (ExTek) was designed that blocked the activation of Tie2 by its activating ligand, angiopoietin 1 (Ang1). Administration of recombinant ExTek protein or an ExTek adenovirus inhibited tumor growth and metastasis in rodent tumor models, demonstrating a functional role for Tie2 in pathological angiogenesis in adult tissues. To begin to understand the endothelial signaling pathways and cellular responses that mediate Tie2 function, we identified signaling molecules that are recruited to the activated, autophosphorylated Tie2 kinase domain. Two of these molecules, SHP2 and GRB2, are part of the pathway upstream of mitogen-activated protein kinase (MAPK) activation, a pathway that may be responsible for morphogenetic effects of Tie2 on endothelial cells. Another signaling molecule, p85, is responsible for recruitment of phosphatidylinositol 3 kinase (PI3-K) and activation of the Akt/PI3-K pathway. Akt/PI3-K has emerged as a critical pathway downstream of Tie2 that is necessary for cell survival effects as well as for chemotaxis, activation of endothelial nitric oxide synthase, and perhaps for anti-inflammatory effects of Tie2 activation. Taken together, these studies and many others demonstrate that the Tie2 pathway has important functions in adult tissues, in both quiescent vasculature and during angiogenesis, and help to validate the Tie2 pathway as a therapeutic target.