Indoleamine 2,3-dioxygenase 1 is essential for sustaining durable antibody responses.

Humoral immunity is essential for protection against pathogens, emphasized by the prevention of 2-3 million deaths worldwide annually by childhood immunizations. Long-term protective immunity is dependent on the continual production of neutralizing antibodies by the subset of long-lived plasma cells (LLPCs). LLPCs are not intrinsically long-lived, but require interaction with LLPC niche stromal cells for survival. However, it remains unclear which and how these interactions sustain LLPC survival and long-term humoral immunity. We now have found that the immunosuppressive enzyme indoleamine 2,3- dioxygenase 1 (IDO1) is required to sustain antibody responses and LLPC survival. Activation of IDO1 occurs upon the engagement of CD80/CD86 on the niche dendritic cells by CD28 on LLPC. Kynurenine, the product of IDO1 catabolism, activates the aryl hydrocarbon receptor in LLPC, reinforcing CD28 expression and survival signaling. These findings expand the immune function of IDO1 and uncover a novel pathway for sustaining LLPC survival and humoral immunity.

Diversity and evolution of nitric oxide reduction in bacteria and archaea.

Nitrous oxide is a potent greenhouse gas whose production is catalyzed by nitric oxide reductase (NOR) members of the heme-copper oxidoreductase (HCO) enzyme superfamily. We identified several previously uncharacterized HCO families, four of which (eNOR, sNOR, gNOR, and nNOR) appear to perform NO reduction. These families have novel active-site structures and several have conserved proton channels, suggesting that they might be able to couple NO reduction to energy conservation. We isolated and biochemically characterized a member of the eNOR family from the bacterium Rhodothermus marinus and found that it performs NO reduction. These recently identified NORs exhibited broad phylogenetic and environmental distributions, greatly expanding the diversity of microbes in nature capable of NO reduction. Phylogenetic analyses further demonstrated that NORs evolved multiple times independently from oxygen reductases, supporting the view that complete denitrification evolved after aerobic respiration.

Industrial-era decline in subarctic Atlantic productivity.

Marine phytoplankton have a crucial role in the modulation of marine-based food webs1, fishery yields2 and the global drawdown of atmospheric carbon dioxide3. However, owing to sparse measurements before satellite monitoring in the twenty-first century, the long-term response of planktonic stocks to climate forcing is unknown. Here, using a continuous, multi-century record of subarctic Atlantic marine productivity, we show that a marked 10 ± 7% decline in net primary productivity has occurred across this highly productive ocean basin over the past two centuries. We support this conclusion by the application of a marine-productivity proxy, established using the signal of the planktonic-derived aerosol methanesulfonic acid, which is commonly identified across an array of Greenlandic ice cores. Using contemporaneous satellite-era observations, we demonstrate the use of this signal as a robust and high-resolution proxy for past variations in spatially integrated marine productivity. We show that the initiation of declining subarctic Atlantic productivity broadly coincides with the onset of Arctic surface warming4, and that productivity strongly covaries with regional sea-surface temperatures and basin-wide gyre circulation strength over recent decades. Taken together, our results suggest that the decline in industrial-era productivity may be evidence of the predicted5 collapse of northern Atlantic planktonic stocks in response to a weakened Atlantic Meridional Overturning Circulation6-8. Continued weakening of this Atlantic Meridional Overturning Circulation, as projected for the twenty-first century9,10, may therefore result in further productivity declines across this globally relevant region.

Growth-dependent Gene Expression Variation Influences the Strength of Codon Usage Biases.

The most highly expressed genes in microbial genomes tend to use a limited set of synonymous codons, often referred to as "preferred codons." The existence of preferred codons is commonly attributed to selection pressures on various aspects of protein translation including accuracy and/or speed. However, gene expression is condition-dependent and even within single-celled organisms transcript and protein abundances can vary depending on a variety of environmental and other factors. Here, we show that growth rate-dependent expression variation is an important constraint that significantly influences the evolution of gene sequences. Using large-scale transcriptomic and proteomic data sets in Escherichia coli and Saccharomyces cerevisiae, we confirm that codon usage biases are strongly associated with gene expression but highlight that this relationship is most pronounced when gene expression measurements are taken during rapid growth conditions. Specifically, genes whose relative expression increases during periods of rapid growth have stronger codon usage biases than comparably expressed genes whose expression decreases during rapid growth conditions. These findings highlight that gene expression measured in any particular condition tells only part of the story regarding the forces shaping the evolution of microbial gene sequences. More generally, our results imply that microbial physiology during rapid growth is critical for explaining long-term translational constraints.

Comparison of herpes simplex virus 1 genomic diversity between adult sexual transmission partners with genital infection.

Herpes simplex virus (HSV) causes chronic infection in the human host, characterized by self-limited episodes of mucosal shedding and lesional disease, with latent infection of neuronal ganglia. The epidemiology of genital herpes has undergone a significant transformation over the past two decades, with the emergence of HSV-1 as a leading cause of first-episode genital herpes in many countries. Though dsDNA viruses are not expected to mutate quickly, it is not yet known to what degree the HSV-1 viral population in a natural host adapts over time, or how often viral population variants are transmitted between hosts. This study provides a comparative genomics analysis for 33 temporally-sampled oral and genital HSV-1 genomes derived from five adult sexual transmission pairs. We found that transmission pairs harbored consensus-level viral genomes with near-complete conservation of nucleotide identity. Examination of within-host minor variants in the viral population revealed both shared and unique patterns of genetic diversity between partners, and between anatomical niches. Additionally, genetic drift was detected from spatiotemporally separated samples in as little as three days. These data expand our prior understanding of the complex interaction between HSV-1 genomics and population dynamics after transmission to new infected persons.

Disparities in Surgical Treatment of Resectable Pancreatic Adenocarcinoma at Minority Serving Hospitals.

INTRODUCTION: Minority serving hospitals (MSH) are those serving a disproportionally high number of minority patients. Previous research has demonstrated that treatment at MSH is associated with worse outcomes. We hypothesize that patients treated at MSH are less likely to undergo surgical resection of pancreatic adenocarcinoma compared to patients treated at non-MSH. METHODS: Patients with resectable pancreatic cancer were identified using the National Cancer Database. Institutions treating Black and Hispanic patients in the top decile were categorized as an MSH. Factors associated with the primary outcome of definitive surgical resection were evaluated using multivariable logistic regression. Univariate and multivariable survival analysis was performed. RESULTS: Of the 75,513 patients included in this study, 7.2% were treated at MSH. Patients treated at MSH were younger, more likely to be uninsured, and higher stage compared to those treated at non-MSH (P < 0.001). Patients treated at MSH underwent surgical resection at lower rates (MSH 40% versus non-MSH 44.5%, P < 0.001). On multivariable logistic regression, treatment at MSH was associated with decreased likelihood of undergoing definitive surgery (odds ratio 0.91, P = 0.006). Of those who underwent surgical resection, multivariable survival analysis revealed that treatment at an MSH was associated with increased morality (hazard ratio 1.12, P < 0.001). CONCLUSIONS: Patients with resectable pancreatic adenocarcinoma treated at MSH are less likely to undergo surgical resection compared to those treated at non-MSH. Targeted interventions are needed to address the unique barriers facing MSH facilities in providing care to patients with pancreatic adenocarcinoma.

The true complexities of "standard" family practice visits unmasked: an observational cross-sectional study in Regina.

BACKGROUND: Many patients present to their family medicine clinic with more than one health concern, placing an increased demand on family physicians. Research into the average number of concerns per regular family medicine visit is limited. Recognition of the frequency that family physicians address more than one concern per visit and adapting practices accordingly is important for improving patient care. OBJECTIVE: To examine whether family physicians routinely address multiple different patient concerns during a single visit and if this is influenced by patient demographics. METHODS: This study was conducted at a multi-physician family medicine clinic in Regina, Saskatchewan, Canada. Five physicians contributed their 500 most recent charts, extending retrospectively from 1 June 2023, from in-person visits by patients over 18 years of age and billed as regular appointments without billed procedures. Each chart was reviewed for the number of concerns addressed in the visit. RESULTS: Fifty percent of visits addressed more than 1 concern (range = 1-8). A generalized linear mixed model using Poisson distribution showed certain physicians (incident rate ratio [IRR]: 1.192, 95% CI: 1.087-1.307, P < 0.001) and adults older than 65 years compared to adults less than 40 years (IRR 1.151, 95% CI: 1.069-1.239, P < 0.001) were more likely to present with multiple concerns, but patient sex was not a significant predictor. CONCLUSIONS: Family physicians routinely address more than one concern per visit. Standard visit length and billing practices should be adapted to reflect this complexity.

Impact of a Palatal Fistula After Cleft Palate Repair on Velopharyngeal Closure.

PURPOSE: A palatal fistula is an adverse outcome of cleft palate repair. It is unknown if a palatal fistula will influence velopharyngeal closure, even after repair of the fistula. This study determines the effect of a soft palate fistula on the risk of developing velopharyngeal insufficiency. METHODS: A retrospective chart review was conducted on patients who underwent primary cleft palate repair between 2000 and 2015, with complete records at 4 years of age. Fistulae involving the secondary palate following primary palatoplasty were classified as the soft or hard palate. A forced-entry multivariate logistic regression model was built to detect predictors of velopharyngeal dysfunction. RESULTS: Records of 329 patients were analyzed with a mean follow-up of 8.7 years. A palatal fistula was identified in 89/329 patients (27%) and 29/329 patients (9%) underwent an independent fistula repair. Of the patients with fistula, 44% were located in the hard palate only and 56% had soft palate involvement. Compared to patients without a fistula, rates of velopharyngeal dysfunction were significantly higher in patients with a fistula involving the soft palate (OR 3.875, CI: 1.964-7.648, P < .001) but not in patients with a hard palate fistula (OR 1.140, CI: 0.497-2.613, P = .757). Veau class, age at primary repair, and syndromic status were not significant predictors of VPI (0.128≤P ≤ .975). CONCLUSIONS: A palatal fistula involving the soft palate is a significant predictor for development of velopharyngeal dysfunction after primary palatoplasty. Surgical intervention, at the time of fistula repair, to add vascularized tissue may be indicated to prophylactically decrease the risk of velopharyngeal dysfunction.

Early patellofemoral cartilage and bone pathology in a rat model of noninvasive anterior cruciate ligament rupture.

OBJECTIVE: Anterior cruciate ligament rupture (ACLR) is a risk factor for the development of post-traumatic osteoarthritis (PTOA). While PTOA in the tibiofemoral joint compartment is well-characterized, very little is known about pathology in the patellofemoral compartment after ACL injury. Here, we evaluated the extent to which ACLR induces early patellofemoral joint damage in a rat model. METHODS: Adult female Lewis rats were randomized to noninvasive ACLR or Sham. Two weeks post-injury, contrast-enhanced micro-computed tomography (µCT) of femoral and patellar cartilage was performed using 20% v/v ioxaglate. Morphometric parameters of femoral trochlear and patellar cartilage, subchondral bone, and trabecular bone were derived from µCT. Sagittal Safranin-O/Fast-Green-stained histologic sections were graded using the OARSI score in a blinded fashion. RESULTS: Cartilage and bone remodelling consistent with an early PTOA phenotype were observed in both femoral trochleas and patellae. ACLR caused osteophyte formation of the patella and pathology in the superficial zone of articular cartilage, including surface fibrillation, fissures, increased cellularity, and abnormal chondrocyte clustering. There were significant increases in thickness of patellar and trochlear cartilage. Loss of subchondral bone thickness, bone volume fraction, and tissue mineral density, as well as changes to patellar and trochlear trabecular microarchitecture, were indicative of catabolic bone remodelling. Several injury-induced changes, including increased cartilage thickness and trabecular spacing and decreased trabecular number were more severe in the patella compared to the trochlea. CONCLUSION: The patellofemoral joint develops mild but evident pathology in the early period following ACL rupture, extending the utility of this model to the study of patellofemoral PTOA.

Increased drug concentration and repeated eye drop administration as strategies to optimize topical drug delivery: A fluorophotometric study in healthy dogs.

OBJECTIVES: Determine tear film kinetics with different fluorescein concentrations and repeated eye drop administration at various time intervals. ANIMALS STUDIED: Six healthy Beagles. PROCEDURES: Six experiments were conducted on separate days: single eye drop administration (control) or two separate eye drops administered at 30 s, 1, 2, 5, and 10 min intervals. For each experiment, one eye received 0.3% fluorescein solution while the other eye received 1% fluorescein solution, and tear fluid was collected with capillary tubes at 0, 1, 5, 10, 20, 30, 40, 50, 60, 90, 120, and 180 min. Fluorescein concentrations were measured using automated fluorophotometry. RESULTS: Compared with 0.3% solution, eyes receiving 1% fluorescein solution had significantly higher tear film concentrations (p ≤ .046) and the area-under-the-fluorescein-time curve was twofold greater (p = .005). Compared with control: (i) Tear film concentrations were significantly higher for up to 20 min when repeating administration 30 s to 5 min after the first drop (p ≤ .006); (ii) The highest increase in area-under-the-curve was obtained with 2 and 5 min intervals for 0.3% (+109%-130%) and 1% solutions (+153%-157%); (iii) The highest increase in median precorneal retention time (defined as tear film concentration < 5% from baseline values) was obtained with 5 min intervals for 0.3% (55 min vs. 15 min in control) and 2-5 min intervals for 1% solutions (50 min vs. 25 min in control). CONCLUSIONS: Drug delivery to the ocular surface can be enhanced by using more concentrated formulations and/or by repeating eye drop administration 2-5 min after the first dose.

Young patients without prior vascular disease are at increased risk of limb loss and reintervention after acute limb ischemia.

BACKGROUND: The objective of the present study was to categorize the presentation and treatment of acute limb ischemia (ALI) in young patients and compare the adverse outcomes after revascularization compared with that of older patients. METHODS: All the patients who had presented to a multi-institution healthcare system with ALI from 2016 to 2020 were identified. The presenting features, operative details, and outcomes were included in the present analysis. Patients with existing peripheral arterial disease (acute on chronic) were analyzed separately from those without (de novo thrombosis or embolus). Within these groups, younger patients (age, ≤50 years) were compared with older patients (age, >50 years). The 3-month major adverse limb event-free survival was the primary outcome. RESULTS: A total of 232 patients (age, 60 ± 16 years; 44% female sex, 87% white race) were included in the analysis. Of the 232 patients, 119 were in the acute on chronic cohort and 113 were in the de novo thrombosis/embolism cohort. Age did not affect the overall outcomes (P = .45) or the outcomes for the acute on chronic group (P = .17). However, in the de novo thrombosis/embolism cohort, patients aged ≤50 years had worse major adverse limb event-free survival compared with patients aged >50 years (hazard ratio, 2.47; 95% confidence interval, 1.08-5.68; P = .03) after adjustment for Rutherford class, interval from presentation to the operating room, and smoking status. In the de novo thrombosis/embolism group, the operative approach was similar across the age groups (endovascular, 12% vs 14%; open, 48% vs 41%; hybrid, 41% vs 45%; P = .78). In the younger patients, embolism was more likely from a proximal arterial source (71%). In contrast, in the older patients, the source of embolism was more often a cardiac source (86%). The rates of hypercoagulable disease were equal across the age groups (10% vs 10%; P = .95). The In-hospital mortality was 3% overall (acute on chronic, 5%; de novo, 3%). CONCLUSIONS: Despite advances in interventional options, for patients with ALI due to de novo thrombosis or embolus, younger age was associated with worse short-term limb-related outcomes.

Quinomycin A reduces cyst progression in polycystic kidney disease.

Polycystic kidney disease (PKD) is a genetic disorder characterized by aberrant renal epithelial cell proliferation and formation and progressive growth of numerous fluid-filled cysts within the kidneys. Previously, we showed that there is elevated Notch signaling compared to normal renal epithelial cells and that Notch signaling contributes to the proliferation of cystic cells. Quinomycin A, a bis-intercalator peptide, has previously been shown to target the Notch signaling pathway and inhibit tumor growth in cancer. Here, we show that Quinomycin A decreased cell proliferation and cyst growth of human ADPKD cyst epithelial cells cultured within a 3D collagen gel. Treatment with Quinomycin A reduced kidney weight to body weight ratio and decreased renal cystic area and fibrosis in Pkd1RC/RC ; Pkd2+/- mice, an orthologous PKD mouse model. This was accompanied by reduced expression of Notch pathway proteins, RBPjk and HeyL and cell proliferation in kidneys of PKD mice. Quinomycin A treatments also normalized cilia length of cyst epithelial cells derived from the collecting ducts. This is the first study to demonstrate that Quinomycin A effectively inhibits PKD progression and suggests that Quinomycin A has potential therapeutic value for PKD patients.

Return to Full Participation Following Concussion in the National Football League, 2015 Through 2020.

OBJECTIVE: Quantify days missed, games missed, injury burden, and time to return to full participation (RTFP) among National Football League (NFL) players who sustained a concussion. DESIGN: Retrospective cohort study. SETTING: 2015 through 2020 NFL seasons. PARTICIPANTS: National Football League players diagnosed with a concussion from 2015 to 2020. INTERVENTIONS: National Football League-mandated graduated RTFP protocol. MAIN OUTCOME MEASURES: Days missed, games missed, burden, and time to RTFP, overall and by position. RESULTS: An annual average of 3639 player-days of participation and 255 games were missed across NFL because of concussion. Concussed players missed a median of 9 days (mean = 15.0), a relatively stable metric over 6 years, with slight variation by position. Offensive linemen, tight ends, running backs, and linebackers missed the most days per concussion; defensive secondary, offensive linemen, and wide receivers sustained the highest injury burden. Postconcussion, 59% of players missed one or more scheduled games. Among players concussed in a Sunday game, 38% played in a Sunday game one week later. CONCLUSIONS: The 9-day median time missed post-concussion may be related to emphasis on graduated phase-based concussion management. No concussed player returned to competition on the day of injury, and less than 40% participated in games the following week. Further work is needed to better understand characteristics of concussions that take longer to return and movement through stages of return.

Diversity and Function of Maternal HIV-1-Specific Antibodies at the Time of Vertical Transmission.

Infants of HIV-positive mothers can acquire HIV infection by various routes, but even in the absence of antiviral treatment, the majority of these infants do not become infected. There is evidence that maternal antibodies provide some protection from infection, but gestational maternal antibodies have not yet been characterized in detail. One of the most studied vertically infected infants is BG505, as the virus from this infant yielded an Envelope protein that was successfully developed as a stable trimer. Here, we isolated and characterized 39 HIV-specific neutralizing monoclonal antibodies (nAbs) from MG505, the mother of BG505, at a time point just prior to vertical transmission. These nAbs belonged to 21 clonal families and employed a variety of VH genes. Many were specific for the HIV-1 Env V3 loop, and this V3 specificity correlated with measurable antibody-dependent cellular cytotoxicity (ADCC) activity. The isolated nAbs did not recapitulate the full breadth of heterologous or autologous virus neutralization by contemporaneous plasma. Notably, we found that the V3-targeting nAb families neutralized one particular maternal Env variant, even though all tested variants had low V3 sequence diversity and were measurably bound by these nAbs. None of the nAbs neutralized BG505 transmitted virus. Furthermore, the MG505 nAb families were found at relatively low frequencies within the maternal B cell repertoire; all were less than 0.25% of total IgG sequences. Our findings illustrate an example of the diversity of HIV-1 nAbs within one mother, cumulatively resulting in a collection of antibody specificities that can contribute to the transmission bottleneck.IMPORTANCE Mother-to-child-transmission of HIV-1 offers a unique setting in which maternal antibodies both within the mother and passively transferred to the infant are present at the time of viral exposure. Untreated HIV-exposed human infants are infected at a rate of 30 to 40%, meaning that some infants do not get infected despite continued exposure to virus. Since the potential of HIV-specific immune responses to provide protection against HIV is a central goal of HIV vaccine design, understanding the nature of maternal antibodies may provide insights into immune mechanisms of protection. In this study, we isolated and characterized HIV-specific antibodies from the mother of an infant whose transmitted virus has been well studied.

Constraints on potential enzyme activities in thermokarst bogs: Implications for the carbon balance of peatlands following thaw.

Northern peatlands store a globally significant amount of soil organic carbon, much of it found in rapidly thawing permafrost. Permafrost thaw in peatlands often leads to the development and expansion of thermokarst bogs, where microbial activity will determine the stability of the carbon storage and the release of greenhouse gases. In this study, we compared potential enzyme activities between young (thawed ~30 years ago) and mature (~200 years) thermokarst bogs, for both shallow and deep peat layers. We found very low potential enzyme activities in deep peat layers, with no differences between the young and mature bogs. Peat quality at depth was found to be highly humified (FTIR analysis) in both the young and mature bogs. This suggests that deep, old peat was largely stable following permafrost thaw, without a rapid pulse of decomposition during the young bog stage. For near-surface peat, we found significantly higher potential enzyme activities in the young bog than in the mature-associated with differences in peat quality derived from different Sphagnum species. A laboratory incubation of near-surface peat showed that differences in potential enzyme activity were primarily influenced by peat type rather than oxygen availability. This suggested that the young bog can have higher rates of near-surface decomposition despite being substantially wetter than the mature bog. Overall, our study shows that peat properties are the dominant constraint on potential enzyme activity and that peatland site development (successional pathways and permafrost history) through its influence on peat type and chemistry is likely to determine peat decomposition following permafrost thaw.

Pregnancy and development of diabetes in First Nations and non-First Nations women in Alberta, Canada.

AIM: To conduct a retrospective population-based study to examine the risk of developing diabetes after delivery in First Nations and non-First Nations women in Alberta. METHODS: Delivery records (1999-2014) were linked to provincial administrative data, which allowed for a maximum follow-up of 16 years after delivery. Prevalence of pregnancy risk factors were compared by First Nations status. Hazard ratios for diabetes after delivery by First Nations status, high pre-pregnancy body weight (≥91 kg) and gestational diabetes status were estimated using the Cox proportional hazards model. RESULTS: Age-adjusted prevalence of gestational diabetes (7.9% vs 4.6%; P<0.0001), high pre-pregnancy body weight (18.8% vs 10.2%; P<0.0001) and diabetes after delivery (3.9% vs 1.1%; P<0.0001) were higher in First Nations women than in non-First Nations women. Development of diabetes after delivery was higher with First Nations status (hazard ratio 3.0, 95% CI 2.6-3.4), high pre-pregnancy body weight (hazard ratio 3.6, 95% CI 3.3-4.0) and gestational diabetes status (hazard ratio 19.2, 95% CI 17.9-20.6). The highest risk was within First Nations women with high pre-pregnancy body weight and gestational diabetes (hazard ratio 54.8, 95% CI 45.2-66.5) compared to women without these three risk factors. Reduced prenatal visits per pregnancy (8.4 vs 10.7; P<0.0001) and delayed first prenatal visit (time to delivery 23.7 vs 26.7 weeks; P<0.0001) were observed in First Nations women compared to non-First Nations women. CONCLUSION: First Nations women are at greater risk of developing diabetes after pregnancy, with gestational diabetes being the strongest predictor. Strategies that target the specific needs of First Nations women before, during and after pregnancy are required.

Globalization of The Journal of Craniofacial Surgery Over The Last Decade: A Continent, Country, and State Level Analysis.

ABSTRACT: Craniofacial surgery continues to be a rapidly evolving field, due in part to interdisciplinary collaboration that has allowed for sharing of knowledge and methodologies, which has expanded greatly due to online journals and publications. The Journal of Craniofacial Surgery (JCS) is a highly regarded journal that has attracted attention for its mission to increase diversity and global representation in manuscript submissions and research publications. The purpose of this study is to provide an objective measurement of global participation in craniofacial research specifically as it pertains to the JCS. Through a bibliometric analysis, the country of origin of all articles published in the JCS from 2010 to 2019 was analyzed. In line with its mission, the JCS increased its overall production 1.9 times during the past decade and increased its global representation 1.6 times, as represented by the number of countries contributing (78). The journal produced 8147 articles with Turkey (1424), USA (1397), China (1178), South Korea (1023), and Italy (644) being the top producers. The highest represented states were Florida (156), New York (130), California (117), Massachusetts (112), and Pennsylvania (106). The Journal of Craniofacial Surgery has the greatest diversity of country representation of the major plastic and reconstructive journals compared. Overall the JCS has stayed true to its mission to foster craniofacial research and is a valuable resource for craniofacial surgeons across the world. This study provides an analysis of trends in global contributions to craniofacial research and highlights areas for further increasing global contributors to the field of craniofacial surgery.

RGS Proteins as Critical Regulators of Motor Function and Their Implications in Parkinson's Disease.

Parkinson disease (PD) is a devastating, largely nonfamilial, age-related disorder caused by the progressive loss of dopamine (DA) neurons in the substantia nigra pars compacta (SNc). Release of DA from these neurons into the dorsal striatum is crucial for regulating movement and their loss causes PD. Unfortunately, the mechanisms underlying SNc neurodegeneration remain unclear, and currently there is no cure for PD, only symptomatic treatments. Recently, several regulator of G protein signaling (RGS) proteins have emerged as critical modulators of PD pathogenesis and/or motor dysfunction and dyskinesia: RGSs 4, 6, 9, and 10. Striatal RGS4 has been shown to exacerbate motor symptoms of DA loss by suppressing M4-autoreceptor-Gα i/o signaling in striatal cholinergic interneurons. RGS6 and RGS9 are key regulators of D2R-Gα i/o signaling in SNc DA neurons and striatal medium spiny neurons, respectively. RGS6, expressed in human and mouse SNc DA neurons, suppresses characteristic PD hallmarks in aged mice, including SNc DA neuron loss, motor deficits, and α-synuclein accumulation. After DA depletion, RGS9 (through its inhibition of medium spiny neuron D2R signaling) suppresses motor dysfunction induced by L-DOPA or D2R-selective agonists. RGS10 is highly expressed in microglia, the brain's resident immune cells. Within the SNc, RGS10 may promote DA neuron survival through the upregulation of prosurvival genes and inhibition of microglial inflammatory factor expression. Thus, RGSs 4, 6, 9, and 10 are critical modulators of cell signaling pathways that promote SNc DA neuron survival and/or proper motor control. Accordingly, these RGS proteins represent novel therapeutic targets for the treatment of PD pathology. SIGNIFICANCE STATEMENT: Parkinson disease (PD), the most common movement disorder, is a progressive neurodegenerative disease characterized by substantia nigra pars compacta (SNc) dopamine (DA) neuron loss and subsequent motor deficits. Current PD therapies only target disease motor symptomology and are fraught with side effects. Therefore, researchers have begun to explore alternative therapeutic options. Regulator of G protein signaling (RGS) proteins, whether primarily expressed in SNc DA neurons (RGS6), striatal neurons (RGSs 4 and 9), or microglia (RGS10), modulate key signaling pathways important for SNc DA neuron survival and/or proper motor control. As such, RGS proteins represent novel therapeutic targets in PD.

Reactive oxygen species (ROS) generation is stimulated by κ opioid receptor activation through phosphorylated c-Jun N-terminal kinase and inhibited by p38 mitogen-activated protein kinase (MAPK) activation.

Activation of the mitogen-activated protein kinase (MAPK) c-Jun N-terminal kinase (JNK) by the Gi/o protein-coupled κ opioid receptor (KOR), µ opioid, and D2 dopamine receptors stimulates peroxiredoxin 6 (PRDX6)-mediated production of reactive oxygen species (ROS). ROS production by KOR-inactivating antagonists norbinaltorphimine (norBNI) and JDTic blocks Gαi protein activation, but the signaling mechanisms and consequences of JNK activation by KOR agonists remain uncharacterized. Binding of arrestins to KOR causes desensitization of G protein signaling and acts as a scaffold to initiate MAPK activation. Here, we found that the KOR agonists U50,488 and dynorphin B stimulated biphasic JNK activation with an early arrestin-independent phase, requiring the small G protein RAC family small GTPase 1 (RAC1) and protein kinase C (PKC), and a later arrestin-scaffolded phase, requiring RAC1 and Ras homolog family member (RHO) kinase. JNK activation by U50,488 and dynorphin B also stimulated PRDX6-dependent ROS production but with an inverted U-shaped dose-response relationship. KOR agonist-induced ROS generation resulted from the early arrestin-independent phase of JNK activation, and this ROS response was suppressed by arrestin-dependent activation of the MAPK p38. The apparent balance between p38 MAPK and JNK/ROS signaling has important physiological implications for understanding of dynorphin activities during the stress response. To visualize these activities, we monitored KOR agonist-mediated activation of ROS in transfected live cells by two fluorescent sensors, CellROX Green and HyPerRed. These findings establish an important aspect of opioid receptor signaling and suggest that ROS induction may be part of the physiological response to KOR activation.

Blood pressure drives multispectral tuning of inspiration via a linked-loop neural network.

The respiratory motor pattern is coordinated with cardiovascular system regulation. Inspiratory drive and respiratory phase durations are tuned by blood pressure and baroreceptor reflexes. We hypothesized that perturbations of systemic arterial blood pressure modulate inspiratory drive through a raphe-pontomedullary network. In 15 adult decerebrate vagotomized neuromuscular-blocked cats, we used multielectrode arrays to record the activities of 704 neurons within the medullary ventral respiratory column, pons, and raphe areas during baroreceptor-evoked perturbations of breathing, as measured by altered peak activity in integrated efferent phrenic nerve activity and changes in respiratory phase durations. Blood pressure was transiently (30 s) elevated or reduced by inflations of an embolectomy catheter in the descending aorta or inferior vena cava. S-transform time-frequency representations were calculated for multiunit phrenic nerve activity and some spike trains to identify changes in rhythmic activity during perturbations. Altered firing rates in response to either or both conditions were detected for 474 of 704 tested cells. Spike trains of 17,805 neuron pairs were evaluated for short-time scale correlational signatures indicative of functional connectivity with standard cross-correlation analysis, supplemented with gravitational clustering; ∼70% of tested (498 of 704) and responding neurons (333 of 474) were involved in a functional correlation with at least one other cell. Changes in high-frequency oscillations in the spiking of inspiratory neurons and the evocation or resetting of slow quasi-periodic fluctuations in the respiratory motor pattern associated with oscillations of arterial pressure were observed. The results support a linked-loop pontomedullary network architecture for multispectral tuning of inspiration.NEW & NOTEWORTHY The brain network that supports cardiorespiratory coupling remains poorly understood. Using multielectrode arrays, we tested the hypothesis that blood pressure and baroreceptor reflexes "tune" the breathing motor pattern via a raphe-pontomedullary network. Neuron responses to changes in arterial pressure and identified functional connectivity, together with altered high frequency and slow Lundberg B-wave oscillations, support a model with linked recurrent inhibitory loops that stabilize the respiratory network and provide a path for transmission of baroreceptor signals.