Widening the Road to Health Professions Education: Expanding Access for Diverse and Underserved Populations.

The Spring 2023 Webinar Audio Seminar (WAS) of the International Association of Medical Science Educators (IAMSE), titled "Widening the Road to Health Professions Education: Expanding Access for Diverse and Underserved Populations," was designed to help health science educators explore innovative practices in recruiting and enrolling students from underserved populations into health sciences programs. From March 2, 2023, to March 30, 2023, this five-part webinar series was broadcast live to institutions and educators worldwide. This series helped participants learn about creating pathways for students to meet the unique needs of their communities.

To Infinity and Beyond: Expanding the Scope of Basic Sciences in Meeting Accreditation Standards.

Interprofessional training, social sciences curricula, service-learning, pre-clerkship integration, and self-directed learning are all cornerstones of medical education and closely align with accreditation elements for most accreditation bodies within health professions education. As a sequel to the Winter 2022 series, the Spring 2022 Webcast Audio Seminar (WAS) of the International Association of Medical Science Educators (IAMSE) continued to examine the evolving roles of basic science educators. From March 3 to March 31, 2022, the five-part webinar series was broadcast live to audiences at academic institutions worldwide; recordings are available on the IAMSE website. This series built a framework through which basic scientists can leverage their content to meet various accreditation standards.

Back to the Future: Maximizing Student Learning and Wellbeing in the Virtual Age.

The virtual age of learning is no longer a concern of the future. It is here. The Fall 2021 Webinar Audio Series (WAS) of the International Association of Medical Science Educators (IAMSE), titled "Back to the Future: Maximizing Student Learning and Wellbeing in the Virtual Age," was designed to help health science educators equip themselves with tools to teach the next generation of health care professionals successfully. From September 2, 2021 to September 30, 2021, the Fall 2021 Series was broadcast live to audiences at academic institutions worldwide in five weekly webinars. This five-part webinar series explored theories and best practices in delivering content over virtual and online media while simultaneously promoting a positive learning environment and enhanced student wellbeing.

USMLE Step-1 is Going to Pass/Fail, Now What Do We Do?

The Winter 2021 Webinar Audio Series (WAS) of the International Association of Medical Science Educators (IAMSE), titled, "USMLE Step-1 is Going to Pass/Fail, Now what do we do?" was broadcast live to audiences at academic institutions worldwide in five weekly webinars from January 7, 2021, to February 4, 2021. Recognized experts from various stakeholder groups discussed the impact of the decision to score the United States Medical Licensing Examination (USMLE) Step 1 exam Pass/Fail (P/F). The speakers identified challenges to their respective programs and explored creative ways to address potential consequences. Sessions included the perspectives of allopathic and osteopathic residency program directors, basic science faculty, undergraduate medical education curriculum designers, clinical educators, and programs for international medical students matriculating to the United States. On February 25, 2021, a bonus session provided cutting-edge updates from a co-chair of the Coalition for Physician Accountability Undergraduate Medical Education (UME) to Graduate Medical Education (GME) Review Committee (UGRC).

Psychomotor impairments and therapeutic implications revealed by a mutation associated with infantile Parkinsonism-Dystonia.

Parkinson disease (PD) is a progressive, neurodegenerative disorder affecting over 6.1 million people worldwide. Although the cause of PD remains unclear, studies of highly penetrant mutations identified in early-onset familial parkinsonism have contributed to our understanding of the molecular mechanisms underlying disease pathology. Dopamine (DA) transporter (DAT) deficiency syndrome (DTDS) is a distinct type of infantile parkinsonism-dystonia that shares key clinical features with PD, including motor deficits (progressive bradykinesia, tremor, hypomimia) and altered DA neurotransmission. Here, we define structural, functional, and behavioral consequences of a Cys substitution at R445 in human DAT (hDAT R445C), identified in a patient with DTDS. We found that this R445 substitution disrupts a phylogenetically conserved intracellular (IC) network of interactions that compromise the hDAT IC gate. This is demonstrated by both Rosetta molecular modeling and fine-grained simulations using hDAT R445C, as well as EPR analysis and X-ray crystallography of the bacterial homolog leucine transporter. Notably, the disruption of this IC network of interactions supported a channel-like intermediate of hDAT and compromised hDAT function. We demonstrate that Drosophila melanogaster expressing hDAT R445C show impaired hDAT activity, which is associated with DA dysfunction in isolated brains and with abnormal behaviors monitored at high-speed time resolution. We show that hDAT R445C Drosophila exhibit motor deficits, lack of motor coordination (i.e. flight coordination) and phenotypic heterogeneity in these behaviors that is typically associated with DTDS and PD. These behaviors are linked with altered dopaminergic signaling stemming from loss of DA neurons and decreased DA availability. We rescued flight coordination with chloroquine, a lysosomal inhibitor that enhanced DAT expression in a heterologous expression system. Together, these studies shed some light on how a DTDS-linked DAT mutation underlies DA dysfunction and, possibly, clinical phenotypes shared by DTDS and PD.

A network of phosphatidylinositol (4,5)-bisphosphate (PIP2) binding sites on the dopamine transporter regulates amphetamine behavior in Drosophila Melanogaster.

Reward modulates the saliency of a specific drug exposure and is essential for the transition to addiction. Numerous human PET-fMRI studies establish a link between midbrain dopamine (DA) release, DA transporter (DAT) availability, and reward responses. However, how and whether DAT function and regulation directly participate in reward processes remains elusive. Here, we developed a novel experimental paradigm in Drosophila melanogaster to study the mechanisms underlying the psychomotor and rewarding properties of amphetamine (AMPH). AMPH principally mediates its pharmacological and behavioral effects by increasing DA availability through the reversal of DAT function (DA efflux). We have previously shown that the phospholipid, phosphatidylinositol (4, 5)-bisphosphate (PIP2), directly interacts with the DAT N-terminus to support DA efflux in response to AMPH. In this study, we demonstrate that the interaction of PIP2 with the DAT N-terminus is critical for AMPH-induced DAT phosphorylation, a process required for DA efflux. We showed that PIP2 also interacts with intracellular loop 4 at R443. Further, we identified that R443 electrostatically regulates DA efflux as part of a coordinated interaction with the phosphorylated N-terminus. In Drosophila, we determined that a neutralizing substitution at R443 inhibited the psychomotor actions of AMPH. We associated this inhibition with a decrease in AMPH-induced DA efflux in isolated fly brains. Notably, we showed that the electrostatic interactions of R443 specifically regulate the rewarding properties of AMPH without affecting AMPH aversion. We present the first evidence linking PIP2, DAT, DA efflux, and phosphorylation processes with AMPH reward.

Zn(2+) reverses functional deficits in a de novo dopamine transporter variant associated with autism spectrum disorder.

Our laboratory recently characterized a novel autism spectrum disorder (ASD)-associated de novo missense mutation in the human dopamine transporter (hDAT) gene SLC6A3 (hDAT T356M). This hDAT variant exhibits dysfunctional forward and reverse transport properties that may contribute to DA dysfunction in ASD. Here, we report that Zn(2+) reverses, at least in part, the functional deficits of ASD-associated hDAT variant T356M. These data suggest that the molecular mechanism targeted by Zn(2+) to restore partial function in hDAT T356M may be a novel therapeutic target to rescue functional deficits in hDAT variants associated with ASD.

Rare autism-associated variants implicate syntaxin 1 (STX1 R26Q) phosphorylation and the dopamine transporter (hDAT R51W) in dopamine neurotransmission and behaviors.

BACKGROUND: Syntaxin 1 (STX1) is a presynaptic plasma membrane protein that coordinates synaptic vesicle fusion. STX1 also regulates the function of neurotransmitter transporters, including the dopamine (DA) transporter (DAT). The DAT is a membrane protein that controls DA homeostasis through the high-affinity re-uptake of synaptically released DA. METHODS: We adopt newly developed animal models and state-of-the-art biophysical techniques to determine the contribution of the identified gene variants to impairments in DA neurotransmission observed in autism spectrum disorder (ASD). OUTCOMES: Here, we characterize two independent autism-associated variants in the genes that encode STX1 and the DAT. We demonstrate that each variant dramatically alters DAT function. We identify molecular mechanisms that converge to inhibit reverse transport of DA and DA-associated behaviors. These mechanisms involve decreased phosphorylation of STX1 at Ser14 mediated by casein kinase 2 as well as a reduction in STX1/DAT interaction. These findings point to STX1/DAT interactions and STX1 phosphorylation as key regulators of DA homeostasis. INTERPRETATION: We determine the molecular identity and the impact of these variants with the intent of defining DA dysfunction and associated behaviors as possible complications of ASD.

PIP2 regulates psychostimulant behaviors through its interaction with a membrane protein.

Phosphatidylinositol (4,5)-bisphosphate (PIP2) regulates the function of ion channels and transporters. Here, we demonstrate that PIP2 directly binds the human dopamine (DA) transporter (hDAT), a key regulator of DA homeostasis and a target of the psychostimulant amphetamine (AMPH). This binding occurs through electrostatic interactions with positively charged hDAT N-terminal residues and is shown to facilitate AMPH-induced, DAT-mediated DA efflux and the psychomotor properties of AMPH. Substitution of these residues with uncharged amino acids reduces hDAT-PIP2 interactions and AMPH-induced DA efflux without altering the hDAT physiological function of DA uptake. We evaluated the significance of this interaction in vivo using locomotion as a behavioral assay in Drosophila melanogaster. Expression of mutated hDAT with reduced PIP2 interaction in Drosophila DA neurons impairs AMPH-induced locomotion without altering basal locomotion. We present what is to our knowledge the first demonstration of how PIP2 interactions with a membrane protein can regulate the behaviors of complex organisms.