Genetically encoded photocrosslinkers locate the high-affinity binding site of antidepressant drugs in the human serotonin transporter.

Despite the well-established role of the human serotonin transporter (hSERT) in the treatment of depression, the molecular details of antidepressant drug binding are still not fully understood. Here we utilize amber codon suppression in a membrane-bound transporter protein to encode photocrosslinking unnatural amino acids (UAAs) into 75 different positions in hSERT. UAAs are incorporated with high specificity, and functionally active transporters have similar transport properties and pharmacological profiles compared with wild-type transporters. We employ ultraviolet-induced crosslinking with p-azido-L-phenylalanine (azF) at selected positions in hSERT to map the binding site of imipramine, a prototypical tricyclic antidepressant, and vortioxetine, a novel multimodal antidepressant. We find that the two antidepressants crosslink with azF incorporated at different positions within the central substrate-binding site of hSERT, while no crosslinking is observed at the vestibular-binding site. Taken together, our data provide direct evidence for defining the high-affinity antidepressant binding site in hSERT.

Characterization of intracellular regions in the human serotonin transporter for phosphorylation sites.

In the central nervous system, synaptic levels of the monoamine neurotransmitter serotonin are mainly controlled by the serotonin transporter (SERT), and drugs used in the treatment of various psychiatric diseases have SERT as primary target. SERT is a phosphoprotein that undergoes phosphorylation/dephosphorylation during transporter regulation by multiple pathways. In particular, activation and/or inhibition of kinases including PKC, PKG, p38MAPK, and CaMKII modulate SERT function and trafficking. The molecular mechanisms by which kinase activity is linked to SERT regulation are poorly understood, including the identity of specific phosphorylated residues. To elucidate SERT phosphorylation sites, we have generated peptides corresponding to the entire intracellular region of human SERT and performed in vitro phosphorylation assays with a panel of kinases suggested to be involved in SERT regulation or for which canonical phosphorylation sites are predicted. Peptide analysis by liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to identify and quantify site-specific phosphorylation. Five residues located in the N- and C-termini and in intracellular loop 1 and 2 were identified as phosphorylation sites; Ser149, Ser277, and Thr603 for PKC, Ser13 for CaMKII, and Thr616 for p38MAPK. Possible regulatory roles of these potential phosphoacceptors for SERT function and surface expression were investigated using phospho-mimicking and phosphodeficient mutations, coexpression of constitutively active kinases and pharmacological kinase induction in a heterologous expression system. Our results suggest that Ser277 is involved in an initial phase of PKC-mediated down-regulation of SERT. The five identified sites can guide future studies of direct links between SERT phosphorylation and regulatory processes.

Interaction of antidepressants with the serotonin and norepinephrine transporters: mutational studies of the S1 substrate binding pocket.

The serotonin transporter (SERT) and the norepinephrine transporter (NET) are sodium-dependent neurotransmitter transporters responsible for reuptake of released serotonin and norepinephrine, respectively, into nerve terminals in the brain. A wide range of inhibitors of SERT and NET are used as treatment of depression and anxiety disorders or as psychostimulant drugs of abuse. Despite their clinical importance, the molecular mechanisms by which various types of antidepressant drugs bind and inhibit SERT and NET are still elusive for the majority of the inhibitors, including the molecular basis for SERT/NET selectivity. Mutational analyses have suggested that a central substrate binding site (denoted the S1 pocket) also harbors an inhibitor binding site. In this study, we determine the effect of mutating six key S1 residues in human SERT (hSERT) and NET (hNET) on the potency of 15 prototypical SERT/NET inhibitors belonging to different drug classes. Analysis of the resulting drug sensitivity profiles provides novel information on drug binding modes in hSERT and hNET and identifies specific S1 residues as important molecular determinants for inhibitor potency and hSERT/hNET selectivity.

SLC6 neurotransmitter transporters: structure, function, and regulation.

The neurotransmitter transporters (NTTs) belonging to the solute carrier 6 (SLC6) gene family (also referred to as the neurotransmitter-sodium-symporter family or Na(+)/Cl(-)-dependent transporters) comprise a group of nine sodium- and chloride-dependent plasma membrane transporters for the monoamine neurotransmitters serotonin (5-hydroxytryptamine), dopamine, and norepinephrine, and the amino acid neurotransmitters GABA and glycine. The SLC6 NTTs are widely expressed in the mammalian brain and play an essential role in regulating neurotransmitter signaling and homeostasis by mediating uptake of released neurotransmitters from the extracellular space into neurons and glial cells. The transporters are targets for a wide range of therapeutic drugs used in treatment of psychiatric diseases, including major depression, anxiety disorders, attention deficit hyperactivity disorder and epilepsy. Furthermore, psychostimulants such as cocaine and amphetamines have the SLC6 NTTs as primary targets. Beginning with the determination of a high-resolution structure of a prokaryotic homolog of the mammalian SLC6 transporters in 2005, the understanding of the molecular structure, function, and pharmacology of these proteins has advanced rapidly. Furthermore, intensive efforts have been directed toward understanding the molecular and cellular mechanisms involved in regulation of the activity of this important class of transporters, leading to new methodological developments and important insights. This review provides an update of these advances and their implications for the current understanding of the SLC6 NTTs.

Improving the stability of α-conotoxin AuIB through N-to-C cyclization: the effect of linker length on stability and activity at nicotinic acetylcholine receptors.

Modification of α-conotoxin frameworks through cyclization via an oligopeptide linker has previously been shown as an effective strategy for improving in vivo stability. We have extended this strategy by investigating cyclic analogs of α-conotoxin AuIB, a selective α(3)ß(4) nicotinic acetylcholine receptor (nAChR) antagonist, to examine a range of oligopeptide linker lengths on the oxidative formation of disulfide bonds, activity at nAChRs, and stability to degradation by chymotrypsin. Upon nondirected random oxidation, the ribbon isomer formed preferentially with the globular isomer occurring as a minor by-product. Therefore, a regioselective disulfide bond forming strategy was used to prepare the cAuIB-2 globular isomer in high yield and purity. The cAuIB-2 globular isomer exhibited a threefold decrease in activity for the α(3)ß(4) nAChR compared to wild-type-AuIB, although it was selective for α(3)ß(4) over α(7) and α(4)ß(2) subtypes. On the other hand, the cAuIB-2 ribbon isomer was shown to be inactive at all three nAChR subtypes. Nonetheless, all of the cyclic analogs were found to be significantly more stable to degradation by chymotrypsin than wild-type AuIB. As such, the cAuIB-2 globular isomer could constitute a useful probe for studying the role of the α(3)ß(4) nAChR in a range of in vivo experimental paradigms.

Patient portals: survey of nursing informaticists.

As the US moves toward a more patient centered health care system, an integrated Electronic Health Record with a Patient Portal is one way that providers and patients can more actively collaborate in the health care process. A patient portal is an Internet-based interactive website for patients to communicate with their healthcare provider and with varied functions that gives them access to portions of their medical record and other services [1,2,3,4]. Many hospitals and health centers in the USA have developed patient portals while others are still in the planning stage. From a review of the literature it is evident that there is no standard of the scope of functions that are essential in the Patient Portals and to date most are only accessible in English. If we are truly moving towards a patient centered focus in health care in a diverse society, we need to design patient portals that tailor these resources to the needs of this diverse population. This paper reports on the results of an online survey that was distributed between August and October 2007 to nursing informaticists who subscribe to the CARING e-mail list and nursing informaticists working in the Greater New York City area. The goal of the survey was to see how many of the institutions where nursing informaticists work had patient portals, what functions were embedded in these portals, what research was being conduct., and what plans each institution had for future directions.

Severity of illness - implications for information management by patients.

As more and more people are living with chronic diseases, there is a greater need for patients to have access to accurate and reliable information about health in general and their own health care in particular. In this study we explored how patients suffering from chronic heart insufficiency who needed post-hospital home nursing care assessed their need for health information and their use of the health information they received. Fourteen patients were interviewed in their homes one week after their discharge. Using a thematic approach, we identified three main areas: the hospital systems for providing information to patients, how patients processed the information, and how patients managed the information. Next of kin had a significant role in information management for the patient. The patient's condition has implications for his or her ability to manage the information, and therefore it seems important to customize information according to the patient's level of comprehension.

Latina breast cancer survivors informational needs: information partners.

The ability to access and understand health information is becoming more critical to managing one's own health and illness. Informatics tools are increasingly the central resources for responding to these needs. But just as information is culturally bound, so are the tools used to access it; both are bounded by the contexts in which they are situated. Latinas face more barriers in accessing needed information due to cultural, linguistic and health access inequities in the US. Although breast cancer rates for Latinas are lower than for non-Latina white women, they are more likely to have a more advanced stage at diagnosis and poorer quality of survivorship. Few studies have explored Latina breast cancer survivors' information needs & strategies. This community-based study focused on Mexican American women with breast cancer and explored their health information experiences, needs, and strategies; it examined their perceptions of how their relationships with providers influenced how information was accessed and utilized. Managing information was not an individual responsibility for any of these women. All of these women had access and used the Internet either directly or through their support networks. All emphasized the importance of having a select support network of people (information partners) for receiving, searching, and interpreting all health information about their illness. If information partners are strategies preferred by Latinas, then we must refocus our assessment of e-health literacy competencies on networks rather than individuals.

Personal health notes: lessons learned.

The health care system is characterized by fragmentation and specialization which challenge the possibility for patients to be well-informed about and involved in their health care. The present study contributes to an in-depth understanding of how we can use patients' own personal health notes to learn about the health care information system and patients' experience of multiple encounters. The personal health note shows different aspects of the health care labyrinths considering the inconsistency as well as discontinuity of the information.

Management of information between two nursing contexts.

This paper presents the results of a study in which hospital and home care nurses were asked to respond to a questionnaire about the structures and content of their information exchange when patients need post-hospital nursing care. The hospital nurses' satisfaction with using an electronic patient record is also reported. The results shows that the organizational context in which nurses work has implications for how the two nursing group assess their information management. The findings are discussed from an information filtering perspective.

Nurses' information management across complex health care organizations.

UNLABELLED: The purpose of this study was to describe the information management used by hospital and home care nurses for patients in need of continuing care after an episode of hospitalization. METHOD: A prospective descriptive design was used. In total 287 hospital nurses and 220 home care nurses were asked to complete a questionnaire before and after the hospital implemented nursing documentation integrated in the electronic patient record (EPR). RESULTS: Discrepancies between the policies expressed by the health care organizations and the authorities in formal documents and the information management used by the nurses were identified. Differences were also found between nurses in hospital and home care with regard to how they assessed the information management during patient admission, throughout the patient's hospital stay and at the patient's discharge. The perceived differences decreased, however, after the hospital introduced electronic nursing documentation. The study shows a need to contextualize and customize the information that nurses exchange. In addition technological problems with the lack of integrated EPR systems between the hospital and the home health care as well as different practice models in the two organizations entail complex information handling during a patient's trajectory through the health system.

Nurses' information management at patients' discharge from hospital to home care.

PURPOSE: The purpose of this paper is to explore and compare hospital and home care nurses' assessment of their information management at patients' discharge from hospital to home care before and after the hospital implemented an electronic nursing discharge note. THEORY: This paper draws on the concept of inter-organizational continuity of care, and specifically addresses the contribution of the implementation of an electronic patient record (EPR). METHODS: The study has a prospective descriptive design. A questionnaire addressing the information that hospital and home care nurses exchange when patients need continuing care after hospitalization was developed and used. RESULTS: Hospital and home care nurses differed in the way they assessed the structures and content of the information they exchanged, both before and after the EPR implementation. CONCLUSION AND DISCUSSION: There is a need to take account of the different organizational contexts within which the two nursing groups work. The organizational context (hospital versus home care) has implications for the nurses' assessment of the information they exchange. In further development of EPR, it is therefore essential to clarify the context-related information needs of the various health care provider groups as part of the commitment to patient safety.

Preparing the next generation of advanced practice nurses.

The Institute of Medicine's vision for health professions education highlights the importance of informatics competencies for all graduates. This paper describes an innovative course, required for all graduate students at the University of Colorado Health Sciences Center School of Nursing. The design, implementation, and evaluation of NURS6013, Human Technology Interface provides evidence to support it as one model for consideration in meeting the Institute of Medicine's vision for health professions education: The course provides learning opportunities which examine the impact of technology on society and health care, informatics and human factors, as well as the legal, ethical, and policy issues related to the use of technology.

Challenging the information gap--the patients transfer from hospital to home health care.

UNLABELLED: The purpose of this paper is to identify the information that nurses in hospitals exchange with nurses in home health care (HHC), and what nurses perceive to be the most significant information to exchange. METHOD: Nurses have an obligation to support and ensure continuity of patient care and to prevent an information gap when patients are transferred from one organizational of health care delivery to another organizational level, for example, from hospital to home health care. In an ongoing prospective study, nurses' pre-electronic nursing discharge note and their assessment of the information it was necessary to exchange at the same time was audited and analyzed. The results show variation in the completeness and content of the nursing discharge note. Nurses' understanding of the scope and content of information to be transmitted varies widely according to the context and the organizational health care level they work within. The implementation of an electronic nursing discharge note creates the opportunity to identify the accurate information elements that must be documented and exchanged between the nurses to ensure patient safety and inter-organizational continuity of care.