Target-agnostic identification of human antibodies to Plasmodium falciparum sexual forms reveals cross stage recognition of glutamate-rich repeats.

Circulating sexual stages of Plasmodium falciparum (Pf) can be transmitted from humans to mosquitoes, thereby furthering the spread of malaria in the population. It is well established that antibodies (Abs) can efficiently block parasite transmission. In search for naturally acquired Ab targets on sexual stages, we established an efficient method for target-agnostic single B cell activation followed by high-throughput selection of human monoclonal antibodies (mAbs) reactive to sexual stages of Pf in the form of gamete and gametocyte extract. We isolated mAbs reactive against a range of Pf proteins including well-established targets Pfs48/45 and Pfs230. One mAb, B1E11K, was cross-reactive to various proteins containing glutamate-rich repetitive elements expressed at different stages of the parasite life cycle. A crystal structure of two B1E11K Fab domains in complex with its main antigen, RESA, expressed on asexual blood stages, showed binding of B1E11K to a repeating epitope motif in a head-to-head conformation engaging in affinity-matured homotypic interactions. Thus, this mode of recognition of Pf proteins, previously described only for PfCSP, extends to other repeats expressed across various stages. The findings augment our understanding of immune-pathogen interactions to repeating elements of the Plasmodium parasite proteome and underscore the potential of the novel mAb identification method used to provide new insights into the natural humoral immune response against Pf . Impact Statement: A naturally acquired human monoclonal antibody recognizes proteins expressed at different stages of the Plasmodium falciparum lifecycle through affinity-matured homotypic interactions with glutamate-rich repeats.

Low-dose inhalation exposure to trichloroethylene induces dopaminergic neurodegeneration in rodents.

Trichloroethylene (TCE) is one of the most pervasive environmental contaminants in the world and is associated with Parkinson disease (PD) risk. Experimental models in rodents show that TCE is selectively toxic to dopaminergic neurons at high doses of ingestion, however, TCE is a highly volatile toxicant, and the primary pathway of human exposure is inhalation. As TCE is a highly lipophilic, volatile organic compound (VOC), inhalation exposure results in rapid diffusion throughout the brain, avoiding first-pass hepatic metabolism that necessitated high doses to recapitulate exposure conditions observed in human populations. We hypothesized that inhalation of TCE would induce significantly more potent neurodegeneration than ingestion and better recapitulate environmental conditions of vapor intrusion or off gassing from liquid TCE. To this end, we developed a novel, whole-body passive exposure inhalation chamber in which we exposed 10-month-old male and female Lewis rats to 50 ppm TCE (time weighted average, TWA) or filtered room air (control) over 8 weeks. In addition, we exposed 12-month-old male and female C57Bl/6 mice to 100 ppm TCE (TWA) or control over 12 weeks. Both rats and mice exposed to chronic TCE inhalation showed significant degeneration of nigrostriatal dopaminergic neurons as well as motor and gait impairments. TCE exposure also induced accumulation of pSer129-αSyn in dopaminergic neurons as well as microglial activation within the substantia nigra of rats. Collectively, these data indicate that TCE inhalation causes highly potent dopaminergic neurodegeneration and recapitulates some of the observed neuropathology associated with PD, providing a future platform for insight into the mechanisms and environmental conditions that influence PD risk from TCE exposure.

Low-dose inhalation exposure to trichloroethylene induces dopaminergic neurodegeneration in rodents.

Trichloroethylene (TCE) is one of the most pervasive environmental contaminants in the world and is associated with Parkinson disease (PD) risk. Experimental models in rodents show that TCE is selectively toxic to dopaminergic neurons at high doses of ingestion, however, TCE is a highly volatile toxicant, and the primary pathway of human exposure is inhalation. As TCE is a highly lipophilic, volatile organic contaminant (VOC), inhalation exposure results in rapid diffusion throughout the brain, avoiding first-pass hepatic metabolism that necessitated high doses to recapitulate exposure conditions observed in human populations. We hypothesized that inhalation of TCE would induce significantly more potent neurodegeneration than ingestion and better recapitulate environmental conditions of vapor intrusion or off gassing from liquid TCE. To this end, we developed a novel, whole-body passive exposure inhalation chamber in which we exposed 10-month-old male and female Lewis rats to 50 ppm TCE (time weighted average, TWA) or filtered room air (control) over 8 weeks. In addition, we exposed 12-month-old male and female C57Bl/6 mice to 100 ppm TCE (TWA) or control over 12 weeks. Both rats and mice exposed to chronic TCE inhalation showed significant degeneration of nigrostriatal dopaminergic neurons as well as motor and gait impairments. TCE exposure also induced accumulation of pSer129-αSyn in dopaminergic neurons as well as microglial activation within the substantia nigra of rats. Collectively, these data indicate that TCE inhalation causes highly potent dopaminergic neurodegeneration and recapitulates some of the observed neuropathology associated with PD, providing a future platform for insight into the mechanisms and environmental conditions that influence PD risk from TCE exposure.

Naturally acquired antibodies to gametocyte antigens are associated with reduced transmission of Plasmodium vivax gametocytes to Anopheles arabiensis mosquitoes.

Naturally acquired antibodies may reduce the transmission of Plasmodium gametocytes to mosquitoes. Here, we investigated associations between antibody prevalence and P. vivax infectivity to mosquitoes. A total of 368 microscopy confirmed P. vivax symptomatic patients were passively recruited from health centers in Ethiopia and supplemented with 56 observations from asymptomatic P. vivax parasite carriers. Direct membrane feeding assays (DMFA) were performed to assess mosquito infectivity; for selected feeds these experiments were also performed after replacing autologous plasma with malaria naïve control serum (n=61). The prevalence of antibodies against 6 sexual stage antigens (Pvs47, Pvs48/45, Pvs230, PvsHAP2, Pvs25 and PvCelTOS) and an array of asexual antigens was determined by ELISA and multiplexed bead-based assays. Gametocyte (ρ< 0.42; p = 0.0001) and parasite (ρ = 0.21; p = 0.0001) densities were positively associated with mosquito infection rates. Antibodies against Pvs47, Pvs230 and Pvs25 were associated with 23 and 34% reductions in mosquito infection rates (p<0.0001), respectively. Individuals who showed evidence of transmission blockade in serum-replacement DMFAs (n=8) were significantly more likely to have PvsHAP2 or Pvs47 antibodies. Further studies may demonstrate causality for the observed associations, improve our understanding of the natural transmission of P. vivax and support vaccine development.

No time to die: An in-depth analysis of James Bond's exposure to infectious agents.

Global travelers, whether tourists or secret agents, are exposed to a smörgåsbord of infectious agents. We hypothesized that agents pre-occupied with espionage and counterterrorism may, at their peril, fail to correctly prioritize travel medicine. To examine our hypothesis, we examined adherence to international travel advice during the 86 international journeys that James Bond was observed to undertake in feature films spanning 1962-2021. Scrutinizing these missions involved ∼3113 min of evening hours per author that could easily have been spent on more pressing societal issues. We uncovered above-average sexual activity, often without sufficient time for an exchange of sexual history, with a remarkably high mortality among Bond's sexual partners (27.1; 95% confidence interval 16.4-40.3). Given how inopportune a bout of diarrhea would be in the midst of world-saving action, it is striking that Bond is seen washing his hands on only two occasions, despite numerous exposures to foodborne pathogens. We hypothesize that his foolhardy courage, sometimes purposefully eliciting life-threatening situations, might even be a consequence of Toxoplasmosis. Bond's approach to vector-borne diseases and neglected tropical diseases is erratic, sometimes following travel advice to the letter, but more often dwelling on the side of complete ignorance. Given the limited time Bond receives to prepare for missions, we urgently ask his employer MI6 to take its responsibility seriously. We only live once.

Exploring human-genome gut-microbiome interaction in Parkinson's disease.

The causes of complex diseases remain an enigma despite decades of epidemiologic research on environmental risks and genome-wide studies that have uncovered tens or hundreds of susceptibility loci for each disease. We hypothesize that the microbiome is the missing link. Genetic studies have shown that overexpression of alpha-synuclein, a key pathological protein in Parkinson's disease (PD), can cause familial PD and variants at alpha-synuclein locus confer risk of idiopathic PD. Recently, dysbiosis of gut microbiome in PD was identified: altered abundances of three microbial clusters were found, one of which was composed of opportunistic pathogens. Using two large datasets, we found evidence that the overabundance of opportunistic pathogens in PD gut is influenced by the host genotype at the alpha-synuclein locus, and that the variants responsible modulate alpha-synuclein expression. Results put forth testable hypotheses on the role of gut microbiome in the pathogenesis of PD, the incomplete penetrance of PD susceptibility genes, and potential triggers of pathology in the gut.

Enteroendocrine cells couple nutrient sensing to nutrient absorption by regulating ion transport.

The ability to absorb ingested nutrients is an essential function of all metazoans and utilizes a wide array of nutrient transporters found on the absorptive enterocytes of the small intestine. A unique population of patients has previously been identified with severe congenital malabsorptive diarrhea upon ingestion of any enteral nutrition. The intestines of these patients are macroscopically normal, but lack enteroendocrine cells (EECs), suggesting an essential role for this rare population of nutrient-sensing cells in regulating macronutrient absorption. Here, we use human and mouse models of EEC deficiency to identify an unappreciated role for the EEC hormone peptide YY in regulating ion-coupled absorption of glucose and dipeptides. We find that peptide YY is required in the small intestine to maintain normal electrophysiology in the presence of vasoactive intestinal polypeptide, a potent stimulator of ion secretion classically produced by enteric neurons. Administration of peptide YY to EEC-deficient mice restores normal electrophysiology, improves glucose and peptide absorption, diminishes diarrhea and rescues postnatal survival. These data suggest that peptide YY is a key regulator of macronutrient absorption in the small intestine and may be a viable therapeutic option to treat patients with electrolyte imbalance and nutrient malabsorption.

Distinct roles for the mTOR pathway in postnatal morphogenesis, maturation and function of pancreatic islets.

While much is known about the molecular pathways that regulate embryonic development and adult homeostasis of the endocrine pancreas, little is known about what regulates early postnatal development and maturation of islets. Given that birth marks the first exposure to enteral nutrition, we investigated how nutrient-regulated signaling pathways influence postnatal islet development in mice. We performed loss-of-function studies of mechanistic target of rapamycin (mTOR), a highly conserved kinase within a nutrient-sensing pathway known to regulate cellular growth, morphogenesis and metabolism. Deletion of Mtor in pancreatic endocrine cells had no significant effect on their embryonic development. However, within the first 2 weeks after birth, mTOR-deficient islets became dysmorphic, ß-cell maturation and function were impaired, and animals lost islet mass. Moreover, we discovered that these distinct functions of mTOR are mediated by separate downstream branches of the pathway, in that mTORC1 (with adaptor protein Raptor) is the main complex mediating the maturation and function of islets, whereas mTORC2 (with adaptor protein Rictor) impacts islet mass and architecture. Taken together, these findings suggest that nutrient sensing may be an essential trigger for postnatal ß-cell maturation and islet development.

Monitoring of Urate-Lowering Therapy Among US Veterans Following the 2012 American College of Rheumatology Guidelines for Management of Gout.

BACKGROUND: With the prevalence of and hospitalizations for gout increasing, optimizing care for patients with gout is imperative. The 2012 American College of Rheumatology gout guidelines emphasize that timely monitoring is key to achieving serum urate (SUA) goals. Few studies have examined this metric following the 2012 update, and to our knowledge, none have examined a veteran population. OBJECTIVE: To evaluate adherence to urate-lowering therapy (ULT) monitoring guidelines in a veteran population. METHODS: This is a single-center, multisite, retrospective chart review of US veterans receiving ULT for gout within the VA (Veterans Affairs) Tennessee Valley Healthcare System from January 1, 2013, to June 30, 2015. The primary end point was percentage of patients with a SUA within 6 months of initial xanthine oxidase inhibitor prescription. Secondary end points included percentage of patients with SUA <6 mg/dL and percentage of patients with uptitration following SUA above goal. RESULTS: A total of 601 patients met inclusion criteria for the study; after application of exclusion criteria, 505 were analyzed. Of these, 295 patients (58%) did not have a SUA drawn within 6 months, and 162 patients (32%) reached the end of the study period without SUA measured. Of 226 patients with SUA above goal on initial check, 64 (28%) had timely dose adjustment, whereas 143 patients (63%) had no adjustment. A total of 161 patients (32%) had a SUA at goal within the study period. CONCLUSIONS: Rates of ULT monitoring at a major VA medical center were suboptimal, and improved adherence to guideline recommendations is needed.

Improving blood pressure control through provider education, provider alerts, and patient education: a cluster randomized trial.

BACKGROUND: Inadequate blood pressure control is a persistent gap in quality care. OBJECTIVE: To evaluate provider and patient interventions to improve blood pressure control. DESIGN: Cluster randomized, controlled trial. SETTING: 2 hospital-based and 8 community-based clinics in the Veterans Affairs Tennessee Valley Healthcare System. PATIENTS: 1341 veterans with essential hypertension cared for by 182 providers. Eligible patients had 2 or more blood pressure measurements greater than 140/90 mm Hg in a 6-month period and were taking a single antihypertensive agent. INTERVENTION: Providers who cared for eligible patients were randomly assigned to receive an e-mail with a Web-based link to the Seventh Report of the Joint National Committee on the Prevention, Detection, Evaluation and Treatment of High Blood Pressure (JNC 7) guidelines (provider education); provider education and a patient-specific hypertension computerized alert (provider education and alert); or provider education, hypertension alert, and patient education, in which patients were sent a letter advocating drug adherence, lifestyle modification, and conversations with providers (patient education). MEASUREMENTS: Proportion of patients with a systolic blood pressure less than 140 mm Hg at 6 months; intensification of antihypertensive medication. RESULTS: Mean baseline blood pressure was 157/83 mm Hg with no differences between groups (P = 0.105). Six-month follow-up data were available for 975 patients (73%). Patients of providers who were randomly assigned to the patient education group had better blood pressure control (138/75 mm Hg) than those in the provider education and alert or provider education alone groups (146/76 mm Hg and 145/78 mm Hg, respectively). More patients in the patient education group had a systolic blood pressure of 140 mm Hg or less compared with those in the provider education or provider education and alert groups (adjusted relative risk for the patient education group compared with the provider education alone group, 1.31 [95% CI, 1.06 to 1.62]; P = 0.012). LIMITATIONS: Follow-up blood pressure measurements were missing for 27% of study patients. The study could not detect a mechanism by which patient education improved blood pressure control. CONCLUSIONS: A multifactorial intervention including patient education improved blood pressure control compared with provider education alone.

A comparison of linear and daily undulating periodized programs with equated volume and intensity for local muscular endurance.

The purpose of this study was to compare linear periodization (LP), daily undulating periodization (DUP), and reverse linear periodization (RLP) for gains in local muscular endurance and strength. Sixty subjects (30 men, 30 women) were randomly assigned to LP, DUP, or RLP groups. Maximal repetitions at 50% of the subject's body weight were recorded for leg extensions as a pretest, midtest, and posttest. Training involved 3 sets (leg extensions) 2 days per week. The LP group performed sets of 25 repetition maximum (RM), 20RM, and 15RM changing every 5 weeks. The RLP group progressed in reverse order (15RM, 20RM, 25RM), changing every 5 weeks. The DUP group adjusted training variables between each workout (25RM, 20RM, 15RM repeated for the 15 weeks). Volume and intensity were equated for each training program. No significant differences were measured in endurance gains between groups (RLP = 73%, LP = 56%, DUP = 55%; p = 0.58). But effect sizes (ES) demonstrated that the RLP treatment (ES = 0.27) was more effective than the LP treatment (control) and the DUP treatment (ES = -0.02) at increasing muscular endurance. Therefore, it was concluded that making gradual increases in volume and gradual decreases in intensity was the most effective program for increasing muscular endurance.

Fractional Utilization of Maximal Aerobic Capacity in Children 6 to 8 Years of Age.

Untrained 6- to 8-year-old children (N= 80) served as subjects in a cross sectional study of the fractional utilization of maximal aerobic power during submaximal running. Using the open-circuit method, the absolute oxygen demands of submaximal running were found to increase with age. When expressed relative to body weight, oxygen demands of submaximal running showed no statistically significant changes over the 3-year span. VO2max increased 36.2%, which was proportionally greater than the percentage increase for either body weight (28.4%) or the absolute oxygen demands of submaximal running (22.9%). Thus, during the span of years studied there was a significant reduction in the fractional utilization of maximal aerobic power required to run at a fixed submaximal speed.