Alared: Solvatochromic and Fluorogenic Red Amino Acid for Ratiometric Live-Cell Imaging of Bioactive Peptides.

To fill the need for environmentally sensitive fluorescent unnatural amino acids able to operate in the red region of the spectrum, we have designed and synthesized Alared, a red solvatochromic and fluorogenic amino acid derived from the Nile Red chromophore. The new unnatural amino acid can be easily integrated into bioactive peptides using classical solid-phase peptide synthesis. The fluorescence quantum yield and the emission maximum of Alared-labeled peptides vary in a broad range depending on the peptide's environment, making Alared a powerful reporter of biomolecular interactions. Due to its red-shifted absorption and emission spectra, Alared-labeled peptides could be followed in living cells with minimal interference from cellular autofluorescence. Using ratiometric fluorescence microscopy, we were able to track the fate of the Alared-labeled peptide agonists of the apelin G protein-coupled receptor upon receptor activation and internalization. Due to its color-shifting environmentally sensitive emission, Alared allowed for distinguishing the fractions of peptides that are specifically bound to the receptor or unspecifically bound to different cellular membranes.

Rapid and Highly Selective Fluorescent Labeling of Peptides via a Thia-Diels-Alder Cycloaddition: Application to Apelin.

Herein, we describe a catalyst-free thia-Diels-Alder cycloaddition for the chemoselective labeling of fully deprotected phosphonodithioester-peptides in solution with fluorophores functionalized with an exocyclic diene. The reaction was optimized on the model tripeptide 1 containing a lysine residue, which enabled its rapid and straightforward labeling with three different fluorophores (fluorescein, lissamine rhodamine B, and squaraine) in very mild conditions (H2O/iPrOH, 37 °C, 1 h). The reaction was then successfully applied to the chemoselective labeling of fully deprotected apelin-13 with squaraine dye. The resulting fluorescent ligand 18 exhibited a high affinity (0.17 ± 0.03 nM) for apelinR. It enabled the development of time-resolved FRET-based competition assays for high-throughput screening and drug discovery. Thanks to its fluorogenic properties, ligand 18 was also successfully involved in the live-cell optical imaging of apelinR in no-wash conditions.

Kinetic and Structural Characterization of the Self-Labeling Protein Tags HaloTag7, SNAP-tag, and CLIP-tag.

The self-labeling protein tags (SLPs) HaloTag7, SNAP-tag, and CLIP-tag allow the covalent labeling of fusion proteins with synthetic molecules for applications in bioimaging and biotechnology. To guide the selection of an SLP-substrate pair and provide guidelines for the design of substrates, we report a systematic and comparative study of the labeling kinetics and substrate specificities of HaloTag7, SNAP-tag, and CLIP-tag. HaloTag7 reaches almost diffusion-limited labeling rate constants with certain rhodamine substrates, which are more than 2 orders of magnitude higher than those of SNAP-tag for the corresponding substrates. SNAP-tag labeling rate constants, however, are less affected by the structure of the label than those of HaloTag7, which vary over 6 orders of magnitude for commonly employed substrates. Determining the crystal structures of HaloTag7 and SNAP-tag labeled with fluorescent substrates allowed us to rationalize their substrate preferences. We also demonstrate how these insights can be exploited to design substrates with improved labeling kinetics.

Access to mental health care among women Veterans: is VA meeting women's needs?

BACKGROUND: Patient-centered access to mental health describes the fit between patient needs and resources of the system. To date, little data are available to guide implementation of services to women veterans, an underrepresented minority within Department of Veteran Affairs (VA) health care. The current study examines access to mental health care among women veterans, and identifies gender-related indicators of perceived access to mental health care. METHODS: A population-based sample of 6287 women veterans using VA primary care services participated in a survey of past year perceived need for mental health care, mental health utilization, and gender-related mental health care experiences. Subjective rating of how well mental health care met their needs was used as an indicator of perceived access. RESULTS: Half of all women reported perceived mental health need; 84.3% of those women received care. Nearly all mental health users (90.9%) used VA services, although only about half (48.8%) reported that their mental health care met their needs completely or very well. Gender related experiences (availability of female providers, women-only treatment settings, women-only treatment groups, and gender-related comfort) were each associated with 2-fold increased odds of perceived access, and associations remained after adjusting for ease of getting care. CONCLUSIONS: Women VA users demonstrate very good objective access to mental health services. Desire for, and access to specialized mental health services for women varies across the population and are important aspects of shared decision making in referral and treatment planning for women using VA primary care.

Military sexual trauma among homeless veterans.

BACKGROUND: Military sexual trauma (MST) is the Veteran Health Administration's (VHA) term for sexual assault and/or sexual harassment that occurs during military service. The experience of MST is associated with a variety of mental health conditions. Preliminary research suggests that MST may be associated with homelessness among female Veterans, although to date MST has not been examined in a national study of both female and male homeless Veterans. OBJECTIVE: To estimate the prevalence of MST, examine the association between MST and mental health conditions, and describe mental health utilization among homeless women and men. DESIGN AND PARTICIPANTS: National, cross-sectional study of 126,598 homeless Veterans who used VHA outpatient care in fiscal year 2010. MAIN MEASURES: All variables were obtained from VHA administrative databases, including MST screening status, ICD-9-CM codes to determine mental health diagnoses, and VHA utilization. KEY RESULTS: Of homeless Veterans in VHA, 39.7 % of females and 3.3 % of males experienced MST. Homeless Veterans who experienced MST demonstrated a significantly higher likelihood of almost all mental health conditions examined as compared to other homeless women and men, including depression, posttraumatic stress disorder, other anxiety disorders, substance use disorders, bipolar disorders, personality disorders, suicide, and, among men only, schizophrenia and psychotic disorders. Nearly all homeless Veterans had at least one mental health visit and Veterans who experienced MST utilized significantly more mental health visits compared to Veterans who did not experience MST. CONCLUSIONS: A substantial proportion of homeless Veterans using VHA services have experienced MST, and those who experienced MST had increased odds of mental health diagnoses. Homeless Veterans who had experienced MST had higher intensity of mental health care utilization and high rates of MST-related mental health care. This study highlights the importance of trauma-informed care among homeless Veterans and the success of VHA homeless programs in providing mental health care to homeless Veterans.

Nile Red-Based GPCR Ligands as Ultrasensitive Probes of the Local Lipid Microenvironment of the Receptor.

The local lipid microenvironment of transmembrane receptors is an essential factor in G protein coupled receptor (GPCR) signaling. However, tools are currently missing for studying endogenously expressed GPCRs in primary cells and tissues. Here, we introduce fluorescent environment-sensitive GPCR ligands for probing the microenvironment of the receptor in living cells using fluorescence microscopy under no-wash conditions. We designed and synthesized antagonist ligands of the oxytocin receptor (OTR) by conjugating a high-affinity nonpeptidic OTR ligand PF-3274167 to the environment-sensitive fluorescent dye Nile Red. The length of the polar PEG spacer between the pharmacophore and the fluorophore was adjusted to lower the nonspecific interactions of the probe while preserving a strong fluorogenic response. We demonstrated that the new probes embed into the lipid bilayer in the vicinity of the receptor and convey information about the local polarity and the lipid order via the wavelength-shifting emission of the Nile Red fluorophore.

Impact of gender on reactions to military sexual assault and harassment.

Research has shown that experiences ofmilitary sexual assault and harassment can have a negative impact on veterans' health and functioning, even years or decades later, thus clearly identifying this as an important area of concern for social workers. In addition to understanding the scope and general impact of military sexual assault and harassment, social workers also must thoroughly understand how different cultural factors may intersect with veterans' experiences. To this end, this article reviews the current knowledge base on how veterans' life experiences related to gender can affect their experience of and recovery from military sexual assault and harassment, highlights common gender-specific issues, and discusses implications for practice.