Developmental stage of transplanted neural progenitor cells influences anatomical and functional outcomes after spinal cord injury in mice.

Neural progenitor cell (NPC) transplantation is a promising therapeutic strategy for replacing lost neurons following spinal cord injury (SCI). However, how graft cellular composition influences regeneration and synaptogenesis of host axon populations, or recovery of motor and sensory functions after SCI, is poorly understood. We transplanted developmentally-restricted spinal cord NPCs, isolated from E11.5-E13.5 mouse embryos, into sites of adult mouse SCI and analyzed graft axon outgrowth, cellular composition, host axon regeneration, and behavior. Earlier-stage grafts exhibited greater axon outgrowth, enrichment for ventral spinal cord interneurons and Group-Z spinal interneurons, and enhanced host 5-HT+ axon regeneration. Later-stage grafts were enriched for late-born dorsal horn interneuronal subtypes and Group-N spinal interneurons, supported more extensive host CGRP+ axon ingrowth, and exacerbated thermal hypersensitivity. Locomotor function was not affected by any type of NPC graft. These findings showcase the role of spinal cord graft cellular composition in determining anatomical and functional outcomes following SCI.

The lysyl oxidase like 2/3 enzymatic inhibitor, PXS-5153A, reduces crosslinks and ameliorates fibrosis.

Fibrosis is characterized by the excessive deposition of extracellular matrix and crosslinked proteins, in particular collagen and elastin, leading to tissue stiffening and disrupted organ function. Lysyl oxidases are key players during this process, as they initiate collagen crosslinking through the oxidation of the ε-amino group of lysine or hydroxylysine on collagen side-chains, which subsequently dimerize to form immature, or trimerize to form mature, collagen crosslinks. The role of LOXL2 in fibrosis and cancer is well documented, however the specific enzymatic function of LOXL2 and LOXL3 during disease is less clear. Herein, we describe the development of PXS-5153A, a novel mechanism based, fast-acting, dual LOXL2/LOXL3 inhibitor, which was used to interrogate the role of these enzymes in models of collagen crosslinking and fibrosis. PXS-5153A dose-dependently reduced LOXL2-mediated collagen oxidation and collagen crosslinking in vitro. In two liver fibrosis models, carbon tetrachloride or streptozotocin/high fat diet-induced, PXS-5153A reduced disease severity and improved liver function by diminishing collagen content and collagen crosslinks. In myocardial infarction, PXS-5153A improved cardiac output. Taken together these results demonstrate that, due to their crucial role in collagen crosslinking, inhibition of the enzymatic activities of LOXL2/LOXL3 represents an innovative therapeutic approach for the treatment of fibrosis.

Beyond two worlds: Identity narratives and the aspirational futures of Alaska Native youth.

Indigenous communities across the Alaskan Arctic have experienced profound revisions of livelihood, culture, and autonomy over the past century of colonization, creating radical discontinuities between the lives of young people and those of their parents and Elders. The disrupted processes of identity development, access to livelihoods, and cross-generational mentorship associated with colonialism have created complex challenges for youth as they envision and enact viable paths forward in the context of a rapidly changing Arctic home. In this study, we consider the meanings associated with different constructions of culture and selfhood, and the ways in which these identity narratives position Inupiaq Alaskan Native youth in relation to their personal and collective futures. Through an intergenerational and participatory inquiry process, this study explores how representations of shared heritage, present-day struggles, resilience, and hope can expand possibilities for youth and thus impact individual and community health.

Rethinking historical trauma.

Recent years have seen the rise of historical trauma as a construct to describe the impact of colonization, cultural suppression, and historical oppression of Indigenous peoples in North America (e.g., Native Americans in the United States, Aboriginal peoples in Canada). The discourses of psychiatry and psychology contribute to the conflation of disparate forms of violence by emphasizing presumptively universal aspects of trauma response. Many proponents of this construct have made explicit analogies to the Holocaust as a way to understand the transgenerational effects of genocide. However, the social, cultural, and psychological contexts of the Holocaust and of post-colonial Indigenous "survivance" differ in many striking ways. Indeed, the comparison suggests that the persistent suffering of Indigenous peoples in the Americas reflects not so much past trauma as ongoing structural violence. The comparative study of genocide and other forms of massive, organized violence can do much to illuminate both common mechanisms and distinctive features, and trace the looping effects from political processes to individual experience and back again. The ethics and pragmatics of individual and collective healing, restitution, resilience, and recovery can be understood in terms of the self-vindicating loops between politics, structural violence, public discourse, and embodied experience.

Central role of relatedness in Alaska native youth resilience: Preliminary themes from one site of the Circumpolar Indigenous Pathways to Adulthood (CIPA) study.

This qualitative study of youth resilience takes place in an Alaska Native community, which has undergone rapid, imposed social change over the last three generations. Elders, and successive generations have grown up in strikingly different social, economic and political contexts. Youth narratives of relationships in the context of adolescent growth and development offer insights to better understand culturally-patterned experience, continuity and change. Local youth and adults shaped the design, implementation and analysis phases of this participatory study. Multiple interviews, totaling 20 older (ages 15-18) and younger (11-14) boys and girls provide accounts of everyday lives and life histories. Although losing close relationships was the most common stressor, many of the participants' resilience strategies centered on their connections to others. Participants cultivated 'relatedness', nurturing relationships that took on kinship qualities. Within these relationships, youth participants acted more responsibly and/or developed a sense of competency and self-worth because of others' reliance on them.

Regulation of vascular leak and recovery from ischemic injury by general and VE-cadherin-restricted miRNA antagonists of miR-27.

Cellular junctions are essential to the normal functioning of the endothelium and control angiogenesis, tissue leak, and inflammation. From a screen of micro RNAs (miRNAs) altered in in vitro angiogenesis, we selected a subset predicted to target junctional molecules. MiR-27a was rapidly downregulated upon stimulation of in vitro angiogenesis, and its level of expression is reduced in neovessels in vivo. The downregulation of miR-27a was essential for angiogenesis because ectopic expression of miR-27a blocked capillary tube formation and angiogenesis. MiR-27a targets the junctional, endothelial-specific cadherin, VE-cadherin. Consistent with this, vascular permeability to vascular endothelial growth factor in mice is reduced by administration of a general miR-27 inhibitor. To determine that VE-cadherin was the dominant target of miR-27a function, we used a novel technology with "Blockmirs," inhibitors that bind to the miR-27 binding site in VE-cadherin. The Blockmir CD5-2 demonstrated specificity for VE-cadherin and inhibited vascular leak in vitro and in vivo. Furthermore, CD5-2 reduced edema, increased capillary density, and potently enhanced recovery from ischemic limb injury in mice. The Blockmir technology offers a refinement in the use of miRNAs, especially for therapy. Further, targeting of endothelial junctional molecules by miRNAs has clinical potential, especially in diseases associated with vascular leak.

Intended transcriptional silencing with siRNA results in gene repression through sequence-specific off-targeting.

Transcriptional gene silencing has been reported with siRNA targeting the promoter region of genes. We tested several siRNAs directed against the human VEGF promoter. Of these, siVFp(-992) exhibited > or =50% suppression of VEGF production in two human cell lines. To determine the specificity of this siRNA-mediated suppression, plasmids were prepared to express a luciferase reporter under the control of VEGF promoters featuring wild-type, mutated, or deleted target sequences. siRNA transfection assays established sequence-specific inhibition of luciferase from the reporter plasmid featuring the wild-type VEGF promoter. However, siVFp(-992) also suppressed the luciferase expression from the plasmids with mutated or deleted target sites, suggesting that silencing was due to a sequence-specific off-target phenomenon, and this was supported by subsequent microarray and bioinformatics analyses. To determine if our concerns regarding the specificity of promoter targeting siRNAs were relevant to other systems where RNA-mediated transcriptional silencing had been previously reported, we tested a published small RNA sequence directed to the HIV(SF2)-LTR promoter. siRNA transfection assays performed in human cells expressing a luciferase reporter gene under the control of the HIV(SF2)-LTR promoter revealed significant suppression whether the target sequence was intact or mutated, or when the entire HIV(SF2)-LTR was replaced by an irrelevant promoter. These data stress the need to examine target specificity when conducting investigations into transcriptional gene regulation with siRNA.