The single port robotic surgical "toolbox": a primer for beginners.

BACKGROUND: The aim of this study is to provide a comprehensive overview of the da Vinci Single Port robotic platform, including instruments and tools that can aid in implementing the use of this novel platform. METHODS: Footage recorded during various Single port robotic urologic procedures and dry labs performed at two US institutions was used as video material. A step-by-step guide illustrating key points on OR set-up, platform, instruments, trocar configurations, intraoperative suctioning, bedside assistance were discussed and highlighted. RESULTS: The Single port surgeon console resembles the Xi console but includes upgraded software. The 6-mm biarticulated instruments incorporate an elbow and a wrist flexible joint. These instruments are deployed through the Access port. Access port kit includes the Access port, and a 25-mm multichannel trocar accommodating an 8-mm flexible scope, and three 6-mm robotic instruments. The 0° endoscope has two sets of articulation: a fixed one, and a distal one, allowing for three movements, selected with a hand command, the "Camera Adjust", the "Camera Control" and the "Relocation." The "Cobra mode," is an extra setting that allows the camera to wing out and move laterally relative to the working instruments. Suction is preferably performed with the Remotely Operated Suction Irrigation system. CONCLUSIONS: Herein we provide a detailed guide to the main technical nuances of the Single port platform and a practical overview of the instrumentation that is used during Single port robotic procedures. Knowledge of the toolbox that is used during Single port robotic surgery is key for those approaching for the first time this novel technology.

Learning Curve for Single-port Robot-assisted Urological Surgery: Single-center Experience and Implications for Adoption.

BACKGROUND AND OBJECTIVE: Understanding the learning curve for the da Vinci single-port (SP) surgical robot is crucial for adoption, training, and enhancement of surgical safety and efficiency. Our aim was to assess the impact of both overall experience (O-EXP) and procedure-specific experience (PS-EXP) on perioperative outcomes across various SP surgeries. METHODS: We analyzed data for 387 consecutive SP surgeries conducted by a high-volume surgeon from December 2018 to July 2023. These included SP robot-assisted radical prostatectomy (SP-RARP), robot-assisted simple prostatectomy (SP-RASP), and robot-assisted nephrectomy (SP-RANP). We used multivariable logistic regression to evaluate the relationship between surgeon experience and outcomes, and locally weighted scatterplot smoothing analysis to graphically explore the risk of postoperative complications according to O-EXP. KEY FINDINGS AND LIMITATIONS: The 387 SP procedures assessed included 172 (44%) SP-RARP, 53 (14%) SP-RASP, and 162 (42%) SP-RANP cases. Overall, 17% of patients had a complication of any grade, 6% experienced severe complications (Clavien-Dindo grade ≥3), and 8% required readmission. Both O-EXP and PS-EXP were associated with a lower risk of complications. The odds ratios for the incidence of complications per increment of 10 procedures were 0.83 (95% confidence interval [CI] 0.76-0.89) for PS-EXP and 0.93 (95% CI 0.90-0.96) for O-EXP. PS-EXP was also associated with a shorter operative time (ß = -3.9, 95% CI -4.9 to -2.9). The risk of complications reached a minimum at 30 SP-RASP, 70 SP-RANP, and 150 SP-RARP cases. Our study is limited by its retrospective design, single-surgeon experience, and lack of functional outcome assessment. CONCLUSIONS AND CLINICAL IMPLICATIONS: Robot-assisted surgery with the da Vinci SP robot has a distinctive learning curve that is influenced by the platform and procedure-specific characteristics. For surgeons new to SP surgery, RASP and renal procedures had the earliest learning curve success and should be approached first, with RARP attempted only when the surgeon has become accustomed to the SP platform. PATIENT SUMMARY: We investigated the learning curve for a surgical robot that uses just one keyhole incision. We found that the time to reach proficiency for urological surgeries with this specific robot, measured as the rate of complications, is faster for some procedures than for more complex operations. This information can help in improving surgeon training and patient safety.

In-silico, Synthesis, Characterization, and In-vitro Studies on Benzylidene-based 2-chloroquinolin Derivatives as Free Radical Scavengers in Parkinson's Disease.

Parkinson's disease is the loss of dopaminergic neurons in the substantial nigra part of the brain leading to neurodegeneration. Whereas, reactive oxygen species and mitochondrial impairment are considered to be the major pathophysiology of neurodegeneration. The benzylidene-based 2-chloroquinolin derivatives were synthesized and characterized by FT-IR, NMR, and MS spectrometry which were screened using various in-silico approaches. The designed compounds were further assessed using in-vitro cytotoxicity assay by the MTT method, DPPH assay, and Glutathione measurements in the SHSY5Y neuroblastoma cell lines. The compounds JD-7 and JD-4 were found to have a binding affinity of - 7.941 and - 7.633 kcal/mol with an MMGBSA score of - 64.614 and - 62.817 kcal/mol. The compound JD-7 showed the highest % Cell viability of 87.64% at a minimal dose of 125 µg/mL by the MTT method. The neurotoxicity effects were observed at increasing concentrations from 0 to 125, 250, and 500 µg/mL. Further, free radical scavenging activity for the JD-7 was found to be 36.55 at lowest 125 µg/mL concentrations. At 125 µg/mL, GSH % and GSSG % were found to be increasing in rotenone treatment, whereas JD-7 and JD-4 were found in the downregulation of glutathione level in the pre-treated rotenone SHSY5Y neuroblastoma cell lines. The benzylidene-based chloroquinolin derivatives were synthesized, and among the compounds JD-1 to JD-13, the compounds JD-7, and JD-4 were found to have having highest % cell viability, free radical scavenging molecules, and glutathione levels in the SHSY5Y neuroblastoma cell lines and could be used as free radical scavengers in Parkinson's disease.

Outpatient vs Inpatient Single-Port Robotic Urologic Surgery: Perioperative Outcomes and Complications.

INTRODUCTION: The da Vinci Single Port (SP) robotic surgical system has minimized the impact of surgery on patients. Hence, outpatient robotic procedures are being explored to reduce costs and improve patient experience. Here, we evaluate the perioperative outcomes and safety of same-day discharge (SDD) after surgery compared to inpatient procedures using the SP. METHODS: A total of 374 patients underwent surgery with the da Vinci SP system between January 2019 and February 2023. Surgeries were performed in a single high-volume center. Patients were either managed with a standardized outpatient or inpatient protocol. SDD clinical pathway was implemented in June 2021. Patients were assessed for discharge eligibility based on specific guidelines. Detailed instructions were provided at discharge, and patients were followed postoperatively. Baseline characteristics, perioperative data, complications, time to complication, and readmissions were assessed. RESULTS: Two hundred eight patients underwent outpatient surgery and 166 underwent inpatient surgery (total = 374). Outpatient surgery was not associated with increased postoperative complications and readmission compared to inpatient surgery. Ninety percent and 74.6% of patients experienced no complications in the outpatient and inpatient populations, respectively (P =< .001). Time to first complication was also comparable between the 2 groups (3 days [IQR 1-8] vs 10 days [IQR 4-30] for outpatient vs inpatient; P = .3). The proportion of successful SDDs increased over time, reaching 88% in October 2022. CONCLUSIONS: Outpatient surgery using the da Vinci SP is safe and feasible, without increasing postoperative complications compared to standard inpatient surgery.

Single port robot-assisted radical and simple prostatectomy: a systematic review and meta-analysis.

BACKGROUND: Aim of our study was to review the current evidence on single port robot-assisted radical prostatectomy (SP-RARP) and SP robot-assisted simple prostatectomy (SP-RASP) procedures. METHODS: A comprehensive bibliographic search on multiple databases was conducted in July 2023. Studies were included if they assessed patients with non-metastatic prostate cancer or candidate for benign prostatic hyperplasia surgery (P) who underwent SP-RARP or SP-RASP, respectively, (I), compared or not with other surgical techniques (C), evaluating perioperative, oncological, or functional outcomes (O). Prospective and retrospective original articles were included (S). A meta-analysis of comparative studies between SP-RARP and MP-RARP was performed. RESULTS: A total of 21 studies investigating 1400 patients were included in our systematic review, 18 were related to SP-RARP while 3 to SP-RASP. Only 8 comparative studies were eligible for meta-analysis. Mean follow-up was 8.1 (±5.8) months. Similar outcomes were observed for SP-RARP and MP-RARP in terms of operative time, catheterization time, pain score, complications rate, continence and potency rates, positive surgical margin, and biochemical recurrence. Length of hospital stay was shorter in the SP group after sensitivity analysis (WMD -0.58, 95% IC -1.17 to -0.9, p < 0.05). Subgroup analysis by extraperitoneal approach did not show any statistical difference, except for a lower positive margins rate in the SP extraperitoneal technique compared to MP-RARP. Overall, SP-RASP exhibited shorter hospital stay and lower rate of de novo urinary incontinence when compared to other techniques, while no differences were reported in terms of postoperative International Prostate Symptom Score, post void residual and maximum flow. CONCLUSIONS: Overall comparable oncological, functional, and perioperative outcomes can be achieved with SP platform. Subgroup analysis by different approaches did not reveal significant variations in outcomes. However, the retrospective nature of the studies, the limited follow-up, and the relatively small sample size of selected Centers may impact these results.

Robot-assisted Surgery in the Field of Urology: The Most Pioneering Approaches 2015-2023.

Robot-assisted surgery has emerged as a transformative technology, revolutionizing surgical approaches and techniques that decades ago could barely be imagined. The field of urology has taken charge in pioneering a new era of minimally invasive surgery with the ascent of robotic systems which offer enhanced visualization, precision, dexterity, and enabling surgeons to perform intricate maneuvers with improved accuracy. This has led to improved surgical outcomes, including reduced blood loss, lower complication rates, and faster patient recovery. The aim of our review is to present an evidence-based critical analysis on the most pioneering robotic urologic approaches described over the last eight years (2015-2023).

Application of the single-port robotic platform during radical nephroureterectomy for upper tract urothelial carcinoma: feasibility of the single-port robot in the multi-quadrant setting.

Urothelial carcinoma of the upper tract (UTUC) is a malignancy that accounts for 5-10% of all urothelial carcinomas. Radical surgery is the primary treatment option due to the high rate of invasive stages at the time of diagnosis. Nephroureterectomy (NU) with bladder cuff excision is the current standard of care. While laparoscopic NU has been established since 1991, many centres still perform open surgery due to the complexity of laparoscopic instrumentation and the steep learning curve for excising the bladder cuff. With the increasing adoption of the multi-port (MP) robotic surgery, NU has increasingly been performed using this platform. The use of MP robotic systems for NU has been challenged by the need for patient repositioning and/or redocking of the robot, which can consume valuable operative time. The transition from the daVinci Si to the daVinci Xi system has seen a noticeable reduction in redocking and patient repositioning. However, owing to the multi-quadrant nature of the surgery in question, the use of multiple ports and external instrument clashing are still persistent problems. Moreover, there is a growing interest in utilizing a retroperitoneal approach for robot-assisted NU due to its potential benefits such as improved control of hilar structures, reduction of blood loss, shorter operative time and hospital stay, reduced complications and decreased postoperative discomfort. The application of the daVinci single-port (SP) robotic platform during radical NU for UTUC is feasible and has the potential to improve the current surgical approach. Indeed, the use of a SP platform may solve the problem of patient repositioning and redocking of the robot, improve superficial aesthetic outcome and minimize external instrument clashing. While maintaining an optimal oncological control, the retroperitoneal approach, which has been difficult to replicate and adopt using the MP approach, may become standard practice. However, more studies are needed to confirm the benefit of this approach and ultimately determine the impact of the daVinci SP on the management of UTUC.

Simplifying Retroperitoneal Robotic Single-port Surgery: Novel Supine Anterior Retroperitoneal Access.

BACKGROUND: Multiport robotic surgery in the retroperitoneum is limited by the bulky robotic frame and clashing of instruments. Moreover, patients are placed in the lateral decubitus position, which has been linked to complications. OBJECTIVE: To assess the feasibility and safety of a supine anterior retroperitoneal access (SARA) technique with the da Vinci Single-Port (SP) robotic platform. DESIGN, SETTING, AND PARTICIPANTS: Between October 2022 and January 2023, 18 patients underwent surgery using the SARA technique for renal cancer, urothelial cancer, or ureteral stenosis. Perioperative variables were prospectively collected and outcomes were assessed. SURGICAL PROCEDURE: With the patient in a supine position, a 3-cm incision is made at the McBurney point and the abdominal muscles are dissected. Finger dissection is used to develop the retroperitoneal space for the da Vinci SP access port. After docking, the first step is to dissect retroperitoneal tissue to reveal the psoas muscle. This allows identification of the ureter, the inferior renal pole, and the hilum. MEASUREMENTS: A descriptive statistical analysis was performed. Data collected included demographics, operative time, warm ischemia time (WIT), surgical margin status, complications, length of hospital stay, 30-d Clavien-Dindo complications, and postoperative narcotic use. RESULTS AND LIMITATIONS: Twelve patients underwent partial nephrectomy (PN) and two each underwent pyeloplasty, radical nephroureterectomy, and radical nephrectomy. In the PN group, mean age was 57 yr (interquartile range [IQR] 30-73), median body mass index was 32 kg/m2 (IQR 17-58), and 25% had stage ≥3 chronic kidney disease. The median Charlson comorbidity index was 3 (IQR 0-7) and 75% of PN patients had an American Society of Anesthesiologists score ≥3. The median RENAL score was 5 (IQR 4-7). The median WIT was 25 min (IQR 16-48) and the median tumor size was 35 mm (IQR 16-50). The median estimated blood loss was 105 ml (IQR 20-400) and the median operative time was 160 min (IQR 110-200). Positive surgical margins were found in one patient. In the overall cohort, one patient was readmitted and managed conservatively; 83% of the PN group were discharged on the same day as their surgery, with the remainder discharged the next day. At 7 d after surgery, no patients reported narcotic use. CONCLUSIONS: The SARA approach is feasible and safe. Larger studies are needed to confirm this approach as a one-step solution for upper urinary tract surgery. PATIENT SUMMARY: We assessed initial outcomes of a novel approach for accessing the retroperitoneum (the space behind the abdominal cavity and in front of the back muscles and spine) during robot-assisted surgery in the upper urinary tract. The patient is placed on their back and surgery is performed with a single-port robot. Our results show that this approach was feasible and safe, with low complication rates, less postoperative pain, and earlier discharge. This is a promising start, but larger studies are needed to confirm our findings.

Single-Port Robot-Assisted Radical Prostatectomy: Where Do We Stand?

In 2018, the da Vinci Single Port (SP) robotic system was approved by the US Food and Drug Administration for urologic procedures. Available studies for the application of SP to prostate cancer surgery are limited. The aim of our study is to summarize the current evidence on the techniques and outcomes of SP robot-assisted radical prostatectomy (SP-RARLP) procedures. A narrative review of the literature was performed in January 2023. Preliminary results suggest that SP-RALP is safe and feasible, and it can offer comparable outcomes to the standard multiport RALP. Extraperitoneal and transvesical SP-RALP appear to be the two most promising approaches, as they offer decreased invasiveness, potentially shorter length of stay, and better pain control. Long-term, high-quality data are missing and further validation with prospective studies across different sites is required.

Multidisciplinary team referral at diagnosis for patients with non-metastatic renal cell carcinoma.

BACKGROUND: To date, multidisciplinary team (MDT) evaluation, enrollment in trials evaluating the role of perioperative therapies and deferred active treatments represent accepted strategies for patients with Renal Cell Carcinoma (RCC), which are under investigation to maximize cancer control and implement health care policies and value-based care. Here, we aimed to identify subgroups of patients with RCC who may benefit from early referral for MDT evaluation at diagnosis in light of an increased risk of recurrence relative to the risk of dying of other causes. METHODS: We relied on a prospective dataset including patients diagnosed with RCC from 1998 to 2019 and treated by means of surgery alone at a tertiary referral center. The risk of other cause mortality (OCM) was evaluated against the risk of distant metastasis over time by means of the Weibull regression. Patients were stratified based on clinical stage (cT1a; cT1b; cT2; cT3-4), age (<60; 60-70; >70) and comorbidities [Charlson comorbidity index (CCI) 0 vs. ≥1]. For each combination of cT stage, age, and CCI, the potential need for an MDT referral was defined when the risk of recurrence exceeded the risk of OCM within the lower limit of the 95% CI of the meantime to recurrence. MAIN FINDINGS: Overall, 1,162 (51%) patients had no comorbidities. Median follow-up was 7 years. Patients who would benefit most from an MDT evaluation are those diagnosed with A) cT3-4 disease (any age or comorbidity) or B) cT2 cancers if healthy and younger than 70 years or younger than 60 years with at least 1 comorbidity or C) cT1b if younger than 60 years and without comorbidities. CONCLUSIONS: Our findings can help selecting the optimal candidates for multidisciplinary evaluations and to consider RCC patients for clinical trials, deferred treatment, and treatment policy improvement. Also, our findings can be useful in the case of major healthcare disruptions, such as pandemics.

Thwarting of Lphn3 Functions in Cell Motility and Signaling by Cancer-Related GAIN Domain Somatic Mutations.

Cancer progression relies on cellular transition states accompanied by changes in the functionality of adhesion molecules. The gene for adhesion G protein-coupled receptor latrophilin-3 (aGPCR Lphn3 or ADGRL3) is targeted by tumor-specific somatic mutations predominantly affecting the conserved GAIN domain where most aGPCRs are cleaved. However, it is unclear how these GAIN domain-altering mutations impact Lphn3 function. Here, we studied Lphn3 cancer-related mutations as a proxy for revealing unknown GAIN domain functions. We found that while intra-GAIN cleavage efficiency was unaltered, most mutations produced a ligand-specific impairment of Lphn3 intercellular adhesion profile paralleled by an increase in cell-matrix actin-dependent contact structures for cells expressing the select S810L mutation. Aberrant remodeling of the intermediate filament vimentin, which was found to coincide with Lphn3-induced modification of nuclear morphology, had less impact on the nuclei of S810L expressing cells. Notoriously, receptor signaling through G13 protein was deficient for all variants bearing non-homologous amino acid substitutions, including the S810L variant. Analysis of cell migration paradigms revealed a non-cell-autonomous impairment in collective cell migration indistinctly of Lphn3 or its cancer-related variants expression, while cell-autonomous motility was potentiated in the presence of Lphn3, but this effect was abolished in S810L GAIN mutant-expressing cells. These data identify the GAIN domain as an important regulator of Lphn3-dependent cell motility, thus furthering our understanding of cellular and molecular events linking Lphn3 genetic somatic mutations to cancer-relevant pathogenesis mechanisms.

In-Stent Restenosis in Saphenous Vein Grafts (from the DIVA Trial).

Saphenous vein grafts (SVGs) have high rates of in-stent restenosis (ISR). We compared the baseline clinical and angiographic characteristics of patients and lesions that did develop ISR with those who did not develop ISR during a median follow-up of 2.7 years in the DIVA study (NCT01121224). We also examined the ISR types using the Mehran classification. ISR developed in 119 out of the 575 DIVA patients (21%), with similar incidence among patients with drug-eluting stents and bare-metal stents (BMS) (21% vs 21%, p = 0.957). Patients in the ISR group were younger (67 ± 7 vs 69 ± 8 years, p = 0.04) and less likely to have heart failure (27% vs 38%, p = 0.03) and SVG lesions with Thrombolysis In Myocardial Infarction 3 flow before the intervention (77% vs 83%, p <0.01), but had a higher number of target SVG lesions (1.33 ± 0.64 vs 1.16 ± 0.42, p <0.01), more stents implanted in the target SVG lesions (1.52 ± 0.80 vs 1.31 ± 0.66, p <0.01), and longer total stent length (31.37 ± 22.11 vs 25.64 ± 17.42 mm, p = 0.01). The incidence of diffuse ISR was similar in patients who received drug-eluting-stents and BMS (57% vs 54%, p = 0.94), but BMS patients were more likely to develop occlusive restenosis (17% vs 33%, p = 0.05).

Role of Radiotherapy in Recurrent Intra-Abdominal Yolk Sac Tumor.

Yolk sac tumor (YST) is a rare malignant germ cell tumor with no appropriate treatment strategy to date. However, patients are treated on a case-to-case basis as per various case reports that have been published. Here, we present a case of 27-year-old female patient who presented to us with chief complaints of severe abdominal pain associated with leucorrhea. She previously had a similar pain episode, which was then evaluated by a multidisciplinary team. She was diagnosed with YST. After that, she underwent 6 cycles of chemotherapy, but there was no improvement. Then the medical oncologist referred her to performed radiotherapy. Then, the radiation oncologist decided to give her curative radiotherapy of 3D-CRT. After completing her sessions, she felt better and clinically improving. After that, she was discharged and scheduled a follow-up visit for first evaluation. At her follow-up visit, she was feeling well, and we decided to have an abdominal MRI.

Ancestry-Tracking of Stress Response GPCR Clades: A Conceptual Path to Treating Depression.

The environmental complexity in which living organisms found themselves throughout evolution, most likely resulted in various encounters that would continuously challenge the organisms' ability to survive. Coping with this stress can prove energetically demanding and might require the proper coupling between mechanisms aimed at sensing external stimuli and cellular strategies geared at producing energy. In this issue of BioEssays, Lovejoy and Hogg hypothesize that preservation of this bifaceted coupling can be detected by the maintenance and evolution of stress response mechanisms at the genomic, molecular and cellular levels. Through ancestry-tracking, they identify a group of related G protein-coupled receptor systems with intersecting stress-modulating properties which might represent an essential part of a complex organism's coping mechanisms to stress, an attribute that they suspect may be affected in individuals suffering from mood disorders such as depression.

Alternative splicing event modifying ADGRL1/latrophilin-1 cytoplasmic tail promotes both opposing and dual cAMP signaling pathways.

The adhesion G protein-coupled receptor ADGRL1/latrophilin-1 (LPHN1) stabilizes synapse formation through heterophilic interactions. A growing consensus is pointing to the role of LPHN1 in modulating intracellular levels of cAMP, although conflicting data exist. Variants of LPHN1 resulting from alternative splicing differ at multiple sites, two of which, designated as SSA and SSB, modify extracellular and intracellular receptor regions, respectively. While SSA splicing modulates receptor-ligand affinity, the function of SSB splicing remains elusive. Here, we explored the role of SSB in an attempt to unify current findings on LPHN1 signaling pathways by testing SSB-containing and SSB-deficient receptor variants in signaling paradigms involving interaction with their ligands neurexin and FLRT. cAMP competitive binding assays revealed that cells expressing either receptor variant exhibited a ligand-dependent decrease in the forskolin-induced cAMP accumulation. Surprisingly, the expression of SSB-containing LPHN1 promoted both constitutive and ligand-dependent cAMP production, whereas SSB-deficient LPHN1 did not. Pertussis toxin treatment unveiled a constitutive coupling to Gαi/o for SSB-containing LPHN1 while abrogating the ligand-mediated activation of Gαs . Importantly, neither receptor variant increased the intracellular concentration of Ca2+ nor MAP kinase activation in the presence of ligands. These results suggest that SSB splicing selectively affects the duality of LPHN1 signaling toward opposing cAMP pathways.

Auxin molecular field maps define AUX1 selectivity: many auxin herbicides are not substrates.

Developmental responses to auxin are regulated by facilitated uptake and efflux, but detailed molecular understanding of the carrier proteins is incomplete. We have used pharmacological tools to explore the chemical space that defines substrate preferences for the auxin uptake carrier AUX1. Total and partial loss-of-function aux1 mutants were assessed against wild-type for dose-dependent resistance to a range of auxins and analogues. We then developed an auxin accumulation assay with associated mathematical modelling to enumerate accurate IC50 values for a small library of auxin analogues. The structure activity relationship data were analysed using molecular field analyses to create a pharmacophoric atlas of AUX1 substrates. The uptake carrier exhibits a very high level of selectivity towards small substrates including the natural indole-3-acetic acid, and the synthetic auxin 2,4-dichlorophenoxyacetic acid. No AUX1 activity was observed for herbicides based on benzoic acid (dicamba), pyridinyloxyacetic acid (triclopyr) or the 6-arylpicolinates (halauxifen), and very low affinity was found for picolinic acid-based auxins (picloram) and quinolinecarboxylic acids (quinclorac). The atlas demonstrates why some widely used auxin herbicides are not, or are very poor substrates. We list molecular descriptors for AUX1 substrates and discuss our findings in terms of herbicide resistance management.

Latrophilins updated.

Latrophilins (LPHN) are part of a yet unexplored family of receptors comprising three isoforms, LPHN1-3, and belonging to a unique branch of G protein-coupled receptors (GPCR) named adhesion GPCR (aGPCR). LPHN are considered to be prototypical models for the study of aGPCR as they are one of the most evolutionary conserved members. Previously described as the target for a potent neurotoxin from the black widow spider venom, LPHN are now being studied under a whole new perspective. Indeed, recent advances have provided a better understanding of different aspects of this prototypical family of receptors: 1) elucidation of LPHN ectodomain organization by crystallography has unveiled a new functional domain with great repercussion on all the other members of the aGPCR family, 2) proteomic approaches have opened the gate to unsuspected functional characteristics of LPHN cellular role, and 3) genetic approaches have provided hints into the physiological functions of LPHN in specific systems and organisms. Moreover, genomic linkage studies screening human patients from diverse genetic backgrounds have involved LPHN gene defects in human disorders such as attention-deficit hyperactivity disorder and cancer. In this review, we will provide a historical perspective addressing experimental research on these receptors while highlighting the new advances and discoveries concerning LPHN functions. As GPCR still represent the most studied targets for the development of pharmacological approaches aiming at alleviating human disorders, the relevance of studying LPHN retains a high pertinence to better understand these receptors for the treatment of human diseases.

Parkinson's disease-linked human PARK9/ATP13A2 maintains zinc homeostasis and promotes α-Synuclein externalization via exosomes.

α-Synuclein plays a central causative role in Parkinson's disease (PD). Increased expression of the P-type ATPase ion pump PARK9/ATP13A2 suppresses α-Synuclein toxicity in primary neurons. Our data indicate that ATP13A2 encodes a zinc pump; neurospheres from a compound heterozygous ATP13A2(-/-) patient and ATP13A2 knockdown cells are sensitive to zinc, whereas ATP13A2 over-expression in primary neurons confers zinc resistance. Reduced ATP13A2 expression significantly decreased vesicular zinc levels, indicating ATP13A2 facilitates transport of zinc into membrane-bound compartments or vesicles. Endogenous ATP13A2 localized to multi-vesicular bodies (MVBs), a late endosomal compartment located at the convergence point of the endosomal and autophagic pathways. Dysfunction in MVBs can cause a range of detrimental effects including lysosomal dysfunction and impaired delivery of endocytosed proteins/autophagy cargo to the lysosome, both of which have been observed in cells with reduced ATP13A2 function. MVBs also serve as the source of intra-luminal nanovesicles released extracellularly as exosomes that can contain a range of cargoes including α-Synuclein. Elevated ATP13A2 expression reduced intracellular α-Synuclein levels and increased α-Synuclein externalization in exosomes >3-fold whereas ATP13A2 knockdown decreased α-Synuclein externalization. An increased export of exosome-associated α-Synuclein may explain why surviving neurons of the substantia nigra pars compacta in sporadic PD patients were observed to over-express ATP13A2. We propose ATP13A2's modulation of zinc levels in MVBs can regulate the biogenesis of exosomes capable of containing α-Synuclein. Our data indicate that ATP13A2 is the first PD-associated gene involved in exosome biogenesis and indicates a potential neuroprotective role of exosomes in PD.

ATP13A2 (PARK9) protein levels are reduced in brain tissue of cases with Lewy bodies.

BACKGROUND: ATP13A2 (PARK9) loss of function mutations are a genetic cause of an early-onset form of Parkinson's disease (PD), with in vitro studies showing that ATP13A2 deficits lead to lysosomal and mitochondrial dysfunction and α-synuclein accumulation, while elevated ATP13A2 expression reduces α-synuclein toxicity. The three human brain tissue studies assessing changes in ATP13A2 expression in PD produced divergent results; mRNA is increased while protein levels were observed to be either increased or decreased. This apparent conflict in protein levels might have arisen from examining Lewy body disease cases with coexisting Alzheimer-type pathologies.To assess whether ATP13A2 levels in Lewy body disease are modified by Alzheimer-type ß-amyloid deposition, we evaluated cases of pure PD and pure dementia with Lewy bodies (DLB) for changes in ATP13A2, α-synuclein and ß-amyloid protein levels in cortical regions with and without Lewy bodies. RESULTS: In all Lewy body disease cases, we identified decreased ATP13A2 protein levels that correlated with increases in both α-synuclein and ß-amyloid. Partial colocalization was observed between ATP13A2 and α-synuclein in Lewy bodies, whereas ATP13A2 did not colocalize with pathological ß-amyloid deposition. CONCLUSIONS: Our data show that patients with Lewy body diseases have an overall deficit in ATP13A2 protein levels, with the remaining protein being more insoluble and partially redistributing towards Lewy bodies. This supports the concept that increasing ATP13A2 levels may offer potential therapeutic benefits to patients with Lewy body diseases.