In-gel protein digestion using acidic methanol produces a highly selective methylation of glutamic acid residues.

Mass-tolerant open search methods allow the high-throughput analysis of modified peptides by mass spectrometry. These techniques have paved the way to unbiased analysis of post-translational modifications in biological contexts, as well as of chemical modifications produced during the manipulation of protein samples. In this work, we have analyzed in-depth a wide variety of samples of different biological origin, including cells, extracellular vesicles, secretomes, centrosomes and tissue preparations, using Comet-ReCom, a recently improved version of the open search engine Comet-PTM. Our results demonstrate that glutamic acid residues undergo intensive methyl esterification when protein digestion is performed using in-gel techniques, but not using gel-free approaches. This effect was highly specific to Glu and was not found for other methylable residues such as Asp.

Reciprocal and Differential Influences of Mediterranean Diet and Physical Activity on Adiposity in a Cohort of Young and Older than 40 Years Adults.

Translational research has documented the conjoint beneficial relationships between dietary and physical activity habits concerning weight maintenance. However, the precise interplay between diet and exercise impacting body composition remains unclear, challenging personalized interventions. This study aimed to explore potential interactions and effect modifications of these factors affecting the body mass index (BMI) within an online adult cohort. Data from 11,883 NUTRiMDEA cohort participants were analyzed in this cross-sectional study, categorizing individuals by age, sex, and BMI using linear regression models to assess the interactions between lifestyle factors and adiposity. Significant differences emerged in anthropometry, lifestyle, and health-related quality of life (HRQoL) across categories. The combined effect of diet and physical activity had a greater impact on BMI than physical activity or Mediterranean diet adherence alone, with lower BMI as physical activity levels increased (ß: -0.5) and adherence to the Mediterranean diet decreased, where a modification effect between them was identified (ß: -0.28). Participants with lower Mediterranean diet adherence displayed superior BMI when physical activity was low, but when activity levels were higher, their BMI aligned with those with healthier dietary habits. An interaction link between lifestyle factors and BMI was found, showing the differential effects of the Mediterranean diet and physical activity combination concerning adiposity.

Feasibility and reliability of a quality indicator system for an ambulatory dispensing service.

Background: For a medication dispensing service to function with quality, continuous evaluation is required, which is why it is necessary to have reliable measurement tools that make it possible. Quality indicators can serve as tools for managing quality, as they are variables that directly or indirectly measure changes in a situation and help evaluate the progress made in addressing it. This article aims to determine the feasibility and reliability of a quality indicator system for a drug dispensing service for paediatric outpatients in two Mexican hospitals. Methods: A study of the development type of health systems and services at a microlevel was conducted from October 2020 to October 2021 in the pharmaceutical service of two Mexican hospitals. To determine the feasibility of the quality indicators, a retrospective evaluation was performed, which considered the indicators that could be calculated with the available information to be feasible. To determine reliability, an inter-observer agreement study (Kappa (κ)) was performed. Results: The feasibility analysis revealed that all five reference indicators related to the structure were feasible in both hospitals. In the Infantil of the Californias hospital, all six process indicators evaluated were feasible, whilst only one was found feasible in H+ Querétaro. As for outcome indicators, only one was feasible in the Infantil of the Californias hospital. The causes of non-feasibility in both hospitals were the non-documentation of the primary data related to the stages of the process and the lack of instruments to measure patient satisfaction. The reliability of the indicators showed little variability. Conclusion: Although not all indicators were feasible, solutions were proposed so that the 15 reference indicators could be used if an organization decided to do so. The reliability of the indicators was demonstrated, evidencing the importance of the data sheet as a tool to generate valid reliable measures.This article is part of the Hospital pharmacy, rational use of medicines and patient safety in Latin America Special Issue: https://www.drugsincontext.com/special_issues/hospital-pharmacy-rational-use-of-medicines-and-patient-safety-in-latin-america/.

Primary follicular lymphoma of the duodenum as an incidental finding on upper gastrointestinal endoscopy.

Primary follicular lymphoma of the duodenum (FLD) is a rare variant of follicular lymphoma (FL), which represents only 1-4% of gastrointestinal non-hodgkin lymphomas (NHL). It usually appears in the second portion of the duodenum as micronodular lesions and the diagnosis is often incidental. Unlike other NHLs, the prognosis is excellent and the treatment ranges from "watch and wait" to rituximab-based immunochemotherapy regimens, depending on the symptoms and the presence of systemic involvement.

Association of microscopic colitis and enteropathy due to olmesartan.

We report the case of a patient with severe chronic diarrhea. He was admitted on multiple occasions for this reason, with the cause remaining undetected. After obtaining a detailed medical history and performing several studies, the patient was diagnosed with microscopic colitis and enteropathy due to Olmesartan. In the literature, both diseases appear concurrently only in a few cases. Here we highlight the importance of conducting a comprehensive medical history and maintaining high clinical suspicion to avoid delays in the diagnosis of these uncommon pathologies, as well as unnecessary tests and empirical treatments.

OnabotulinumtoxinA as a promising treatment for primary trochlear headache: A retrospective case series.

OBJECTIVES: To report the efficacy of onabotulinumtoxinA (BoNTA) injections in relieving pain in patients with primary trochlear headache (PRTH). METHODS: Examination of medical records for patients diagnosed with PRTH according to the International Classification of Headache Disorders, 3rd edition criteria and treated with BoNTA. Data were collected for variables related to pain relief, duration of effectiveness, and adverse effects. RESULTS: Six patients were included in the study. All had previously undergone standard care interventions, including infiltrations or oral treatments, yet experienced treatment failure or symptom recurrence. All patients received 20 units of BoNTA, administered in the corrugator and procerus muscles. Subsequent to the BoNTA injections, all six patients reported substantial pain relief, with five achieving complete remission of symptoms. The analgesic effect persisted for a duration of 3 months. No adverse events were reported in any of the cases. CONCLUSIONS: Our case series presents the first evidence of the potential of BoNTA as a safe and effective treatment option for PRTH. From a clinical standpoint, having a safer alternative is of paramount significance for patients with limited treatment options, such as those with PRTH. Further research is warranted to validate these findings and explore the long-term efficacy of BoNTA in PRTH management.

Quality of Recovery After Unplanned and Planned Cesarean Deliveries: A Prospective Observational Study Using the Obstetric Quality of Recovery-10 Tool.

BACKGROUND: There is a paucity of literature examining the differences between patient-reported outcome measures after planned and unplanned cesarean delivery using a validated quality of recovery tool. The Obstetric Quality of Recovery-10 (ObsQoR-10) scoring tool has been validated to quantify functional recovery after cesarean delivery. We aimed to use the ObsQoR-10 to compare the postoperative recovery characteristics of patients undergoing planned and unplanned cesarean deliveries. METHODS: We conducted a prospective single-center observational study. Patients undergoing planned and unplanned cesarean deliveries under neuraxial anesthesia were asked to complete the ObsQoR-10 questionnaire 24 hours, 48 hours, and 1 week postpartum. We collected information on total in-hospital postoperative opioid consumption and patients´ perception of readiness for discharge at 24 and 48 hours postpartum. Additionally, patient characteristics were collected to assess their correlation with our findings. RESULTS: We included 112 patients (56 in each group). No statistical differences in ObsQoR-10 scores at 24 hours, 48 hours, and 1 week postpartum were observed between the planned and unplanned cesarean deliveries. Additionally, there was no difference between the groups in patients' perception of readiness for hospital discharge at 24 and 48 hours and opioid consumption in the first 2 days after surgery. Most patients in both groups did not think they would be ready for discharge at 24 hours postpartum. Analysis of the individual components of ObsQoR-10 at 24 hours showed a difference in the responses assessing the severity of shivering (higher in unplanned cesarean deliveries) and the ability to look after personal hygiene (lower in unplanned cesarean deliveries). CONCLUSIONS: As assessed by the ObsQoR-10, no significant difference in the quality of recovery was observed between patients undergoing planned and unplanned cesarean delivery.

Immune and metabolic challenges induce changes in pain sensation and related pathways in the hypothalamus.

The hypothalamic molecular processes participate in the regulation of the neuro-immune-endocrine system, including hormone, metabolite, chemokine circulation, and corresponding physiological and behavioral responses. RNA-sequencing profiles were analyzed to understand the effect of juvenile immune and metabolic distress 100 days after virally elicited maternal immune activation during gestation in pigs. Over 1,300 genes exhibited significant additive or interacting effects of gestational immune activation, juvenile distress, and sex. One-third of these genes presented multiple effects, emphasizing the complex interplay of these factors. Key functional categories enriched among affected genes included sensory perception of pain, steroidogenesis, prolactin, neuropeptide, and inflammatory signaling. These categories underscore the intricate relationship between gestational immune activation during gestation, distress, and the response of hypothalamic pathways to insults. These effects were sex-dependent for many genes, such as Prdm12, Oprd1, Isg20, Prl, Oxt, and Vip. The prevalence of differentially expressed genes annotated to proinflammatory and cell cycle processes suggests potential implications for synaptic plasticity and neuronal survival. The gene profiles affected by immune activation, distress, and sex pointed to the action of transcription factors SHOX2, STAT1, and REST. These findings underscore the importance of considering sex and postnatal challenges when studying causes of neurodevelopmental disorders and highlight the complexity of the "two-hit" hypothesis in understanding their etiology. Our study furthers the understanding of the intricate molecular responses in the hypothalamus to gestational immune activation and subsequent distress, shedding light on the sex-specific effects and the potential long-lasting consequences on pain perception, neuroendocrine regulation, and inflammatory processes.NEW & NOTEWORTHY The interaction of infection during gestation and insults later in life influences the molecular mechanisms in the hypothalamus that participate in pain sensation. The response of the hypothalamic transcriptome varies between sexes and can also affect synapses and immune signals. The findings from this study assist in the identification of agonists or antagonists that can guide pretranslational studies to ameliorate the effects of gestational insults interacting with postnatal challenges on physiological or behavioral disorders.

Association of Systemic Lupus Erythematosus Disease Activity With Choroidal Thickness.

OBJECTIVE: To determine the association between disease activity and choroidal thickness in patients with systemic lupus erythematosus (SLE). METHODS: We conducted a cohort study of 24 SLE patients and 13 healthy controls recruited at Washington University School of Medicine between June 2019 and November 2021. SLE disease activity was assessed using the SLE Disease Activity Index-2000 Responder Index-50 (S2K RI-50). Patients were divided into four groups: high disease activity/no lupus nephritis (HDA/no LN; S2K RI-50 > 4), HDA/active LN (HDA/active LN; S2K RI-50 > 4), low disease activity/inactive LN (LDA/inactive LN; S2K RI-50 ≤ 4), and LDA/no LN (LDA/no LN; S2K RI-50 ≤ 4). LDA/no LN patients were age-, sex-, and race-matched to healthy controls and patients in other SLE groups. Choroidal thickness of the right eye was measured blinded to disease activity on a horizontal section through the fovea on optical coherence tomography images taken within a week of disease assessment. RESULTS: Patients with HDA had choroidal thickening compared with matched patients with LDA. After controlling for multiplicity, choroidal thinning remained statistically significant at 1000 µm nasal to the fovea (308 ± 68 vs 228 ± 64 µm, p = 0.001). Choroidal thickness was not different between LDA/no LN and LDA/inactive LN or healthy controls. CONCLUSION: HDA in patient with SLE is associated with increased choroidal thickness whereas comorbid inactive LN did not affect choroidal thickness. Additional studies in a larger longitudinal cohort are needed to study whether choroidal thickness may be used as a noninvasive, adjunctive measure for disease activity in SLE.

Assessment of Water, Sanitation, and Hygiene Conditions in Public Elementary Schools in Quetzaltenango, Guatemala, in the Context of the COVID-19 Pandemic.

Water, sanitation, and hygiene (WASH) services in schools are essential to reduce infectious disease transmission, including that of COVID-19. This study aimed to establish a baseline of WASH services in six public elementary schools in Guatemala, with a focus on hand hygiene. We used the WHO/UNICEF Joint Monitoring Programme (JMP) report indicators to assess the WASH infrastructure at each school. We collected water samples from easily accessible water points (pilas, or bathroom sinks) at each school to test for the presence of total coliforms and E. coli. In-depth interviews were carried out with teachers to understand hand hygiene practices and systems at school. Results indicate that all schools had water available at the time of the survey. All water samples at four schools tested positive for total coliforms and at one school, positive for E. coli. All schools had sanitation facilities, but services were limited. Only 43% of handwashing stations at schools had soap available. No school had disability-inclusive WASH services. Financial constraints and a lack of appropriate WASH infrastructure were the main barriers reported by teachers to meet hand hygiene needs at school. Appropriate access to WASH infrastructure and supplies could increase hand hygiene practices and improve learning conditions for students.

Ultra-processed food consumption and nutritional status in Uruguayan and Brazilian children between three to five years / Consumo de alimentos ultraprocesados y estado nutricional en niños de tres a cinco años uruguayos y brasileños

Introduction. There is growing consensus globally that the consumption of ultra- processed food (UPF) can negatively affect the nutritional status of children. Objective. The present study aims to evaluate associations between the consumption of UPF and the nutritional status in a sample of Uruguayan and Brazilian preschoolers belonging to two studies: the ENDIS Study and the Pelotas 2015 Birth Cohort. Materials and methods. We conducted a cross-sectional analysis. The main outcome measure was obesity defined as BMI for age and sex ≥ +3 z-scores. The score of UPF consumption was the main exposure measured. Each positive answer of habitual intake was added up to create a UPF score ranging from zero to six or more UPF. Crude and adjusted logistic regressions were performed for the associations between UPF consumption and nutritional status in preschoolers. Results. The final sample consisted of 8,687 preschool children, 50.8% belonging to the Uruguayan study, while the remaining 49.2% belonged to the Brazilian study. Nearly 5% of the sample of young children were obese. We didn't observe a relationship between the score of UPF consumption and obesity, the odds ratio (OR) was 1.04 (95% CI, 1.00­1.09). Adjustments resulted in modest attenuation of the relationship and a lack of statistical significance. However, in children under 48 months, the score of UPF consumption was directly associated with childhood obesity. Conclusions. Results suggest that higher consumption of UPF is associated with obesity in Uruguayan and Brazilian preschool children under 4 years of age. These findings suggest that actions to reduce ultra- processed food consumption could lead to diminish obesity patterns and bring important public health benefits(AU)

Introducción. Existe creciente consenso a nivel mundial de que el consumo de alimentos ultraprocesados puede afectar negativamente el estado nutricional de los niños. Objetivo. El presente estudio tiene como objetivo evaluar asociaciones entre el consumo de ultraprocesados y el estado nutricional en una muestra de preescolares uruguayos y brasileños pertenecientes a dos estudios: el Estudio ENDIS y la Cohorte de Nacimiento de Pelotas 2015. Materiales y métodos. Se realizó un análisis transversal. La principal medida de resultado fue la obesidad definida como el IMC/edad y sexo ≥ +3 puntuaciones z. La puntuación del consumo de ultraprocesados fue la principal exposición. Cada respuesta positiva de la ingesta habitual se sumó para crear una puntuación de ultraprocesados que oscilaba entre cero y seis o más. Se realizaron regresiones logísticas crudas y ajustadas. Resultados. La muestra final estuvo constituida por 8.687 niños, de los cuales el 50,8% pertenecía al estudio uruguayo, mientras que el 49,2% restante pertenecía al estudio brasileño. Casi el 5% de la muestra de niños pequeños eran obesos. No observamos relación entre la puntuación del consumo de ultraprocesados y la obesidad, el odds ratio (OR) fue de 1,04 (IC 95%, 1,00-1,09). Los ajustes dieron lugar a modesta atenuación de la relación y falta de significación estadística. Sin embargo, en menores de 48 meses la puntuación de consumo de ultraprocesados se asoció directamente con la obesidad infantil. Conclusiones. Los resultados sugieren que un mayor consumo de ultraprocesados se asocia con obesidad en prescolares uruguayos y brasileños menores de 4 años. Estos hallazgos sugieren que las acciones para reducir el consumo de alimentos ultraprocesados podrían conducir a una disminución de los patrones de obesidad y traer importantes beneficios para la salud pública(AU)

ReCom: A semi-supervised approach to ultra-tolerant database search for improved identification of modified peptides.

Open-search methods allow unbiased, high-throughput identification of post-translational modifications in proteins at an unprecedented scale. The performance of current open-search algorithms is diminished by experimental errors in the determination of the precursor peptide mass. In this work we propose a semi-supervised open search approach, called ReCom, that minimizes this effect by taking advantage of a priori known information from a reference database, such as Unimod or a database provided by the user. We present a proof-of-concept study using Comet-ReCom, an improved version of Comet-PTM. Comet-ReCom increased identification performance of Comet-PTM by 68%. This increased performance of Comet-ReCom to score the MS/MS spectrum comes in parallel with a significantly better assignation of the monoisotopic peak of the precursor peptide in the MS spectrum, even in cases of peptide coelution. Our data demonstrate that open searches using ultra-tolerant mass windows can benefit from using a semi-supervised approach that takes advantage from previous knowledge on the nature of protein modifications. SIGNIFICANCE: The present study introduces a novel approach to ultra-tolerant database search, which employs prior knowledge of post-translational modifications (PTMs) to improve identification of modified peptides. This method addresses the limitations related to experimental errors and precursor mass assignation of previous open-search methods. Thus, it enables the study of the biological significance of a wider variety of PTMs, including unknown or unexpected modifications that may have gone unnoticed using non-supervised search methods.

Colonization With Antibiotic-Resistant Bacteria in a Hospital and Associated Communities in Guatemala: An Antibiotic Resistance in Communities and Hospitals (ARCH) Study.

BACKGROUND: We estimated the prevalence of colonization with extended-spectrum cephalosporin-resistant Enterobacterales (ESCrE) and carbapenem-resistant Enterobacterales (CRE) from a hospital and associated communities in western Guatemala. METHODS: Randomly selected infants, children, and adults (<1, 1-17, and ≥18 years, respectively) were enrolled from the hospital (n = 641) during the coronavirus disease 2019 (COVID-19) pandemic, March to September 2021. Community participants were enrolled using a 3-stage cluster design between November 2019 and March 2020 (phase 1, n = 381) and between July 2020 and May 2021 (phase 2, with COVID-19 pandemic restrictions, n = 538). Stool samples were streaked onto selective chromogenic agar, and a Vitek 2 instrument was used to verify ESCrE or CRE classification. Prevalence estimates were weighted to account for sampling design. RESULTS: The prevalence of colonization with ESCrE and CRE was higher among hospital patients compared to community participants (ESCrE: 67% vs 46%, P < .01; CRE: 37% vs 1%, P < .01). Hospital ESCrE colonization was higher for adults (72%) compared with children (65%) and infants (60%) (P < .05). Colonization was higher for adults (50%) than children (40%) in the community (P < .05). There was no difference in ESCrE colonization between phase 1 and 2 (45% and 47%, respectively, P > .05), although reported use of antibiotics among households declined (23% and 7%, respectively, P < .001). CONCLUSIONS: While hospitals remain foci for ESCrE and CRE colonization, consistent with the need for infection control programs, community prevalence of ESCrE in this study was high, potentially adding to colonization pressure and transmission in healthcare settings. Better understanding of transmission dynamics and age-related factors is needed.

Estimación del gasto en salud mental en Chile 2014 - 2021 / Estimated spending on mental health in Chile 2014 - 2021

Los desafíos en salud mental en Chile son múltiples y complejos. Por ello, la valorización de los recursos existentes permite establecer una línea base para mejorar el acceso, la cobertura y la efectividad de las medidas. El presente artículo tiene por objetivo estimar y analizar el gasto en salud mental realizado en Chile entre 2014 y 2021, abordando tanto la atención no ambulatoria como la ambulatoria. Así, el cálculo de los gastos en atención no ambulatoria para salud mental se obtuvo de la metodología de gasto por enfermedad (11,7% del total). Por otro lado, la estimación en atención ambulatoria para salud mental consideró múltiples fuentes de información por niveles de atención público y privado (56,9%). Adicionalmente, se estimaron los gastos en medicamentos realizados por las personas en el retail (31,4%). El gasto estimado en salud mental público alcanzó los $208 miles de millones, lo que representa un 1,7% del gasto público en salud de Chile el 2021. Asimismo, a nivel privado el gasto en salud mental fue de $332 miles de millones, esto es un 3,4% del gasto privado en salud. Además, se resalta la relevancia de considerar los costos asociados al reposo médico por salud mental que son 2 veces más que el gasto estimado. Se concluye comparando las estimaciones con otros países, mencionando limitaciones por falta de acceso a la información y algunos desafíos. Además, se destaca el problema de acceso a las prestaciones debido al alto porcentaje de copago (66%), y la necesidad de aumentar el presupuesto público destinado a la salud mental.

Phenotypic Characteristics and Clonal Relationships of Stenotrophomonas maltophilia Isolates in Hospitalized Adults from a Private Center in Lima, Peru.

Stenotrophomonas maltophilia is an opportunistic pathogen, often associated with nosocomial infections. Ten S. maltophilia were isolated from clinical samples during the period January 2021 and June 2022. Eight (80%) patients had cancer as a background disease and 2 patients had coronavirus disease 2019. A fatal outcome was recorded in 4 cases (40% of patients). All the isolates were susceptible to minocycline and levofloxacin. Trimethoprim/sulfamethoxazole and ceftazidime resistance rates were 20% and 40% respectively. Eight different patterns were observed by Pulsed-Field Gel Electrophoresis, only two isolates being clonally identical. The isolation of S. maltophilia in clinical settings requires the implementation of infection prevention measures.

Towards a leptospirosis early warning system in northeastern Argentina.

Leptospirosis is a zoonotic disease with a high burden in Latin America, including northeastern Argentina, where flooding events linked to El Niño are associated with leptospirosis outbreaks. The aim of this study was to evaluate the value of using hydrometeorological indicators to predict leptospirosis outbreaks in this region. We quantified the effects of El Niño, precipitation, and river height on leptospirosis risk in Santa Fe and Entre Ríos provinces between 2009 and 2020, using a Bayesian modelling framework. Based on several goodness of fit statistics, we selected candidate models using a long-lead El Niño 3.4 index and shorter lead local climate variables. We then tested predictive performance to detect leptospirosis outbreaks using a two-stage early warning approach. Three-month lagged Niño 3.4 index and one-month lagged precipitation and river height were positively associated with an increase in leptospirosis cases in both provinces. El Niño models correctly detected 89% of outbreaks, while short-lead local models gave similar detection rates with a lower number of false positives. Our results show that climatic events are strong drivers of leptospirosis incidence in northeastern Argentina. Therefore, a leptospirosis outbreak prediction tool driven by hydrometeorological indicators could form part of an early warning and response system in the region.

Workshop, Assessment, and Validity Evidence for Tools Measuring Performance of Knee and Shoulder Arthrocentesis.

Introduction: Musculoskeletal concerns are common, yet residents at our institution lacked arthrocentesis training. We created a workshop to teach residents knee and shoulder arthrocentesis, developed simulated assessment scenarios (SASs) with tools to measure procedural proficiency, and collected validity evidence. Methods: A multidisciplinary group conducted a modified Delphi to define content for the workshop, SASs, and assessment tools. We defined minimum thresholds for competence in knee and shoulder arthrocentesis using the modified borderline-group method. We implemented the workshop and SASs in 2020 and 2021 and analyzed assessment tool scoring for statistical reliability and validity. Our program evaluation included SAS performance, participants' survey responses, and change in the number of arthrocenteses performed in the internal medicine (IM) resident primary care clinic. Results: Sixty-one residents (53 IM, eight physical medicine and rehabilitation [PM&R]) participated. Fifty-two (85%; 46 IM, six PM&R) completed the evaluation survey. We procured data from 48 knee and 65 shoulder SASs for validity evidence. All arthrocentesis SAS performances met the proficiency standard except one resident's shoulder SAS. Validity evidence revealed strong interrater reliability (α = .82 and .77 for knee and shoulder, respectively) and strong relational validity (p < .001 for both procedures). All participants rated workshop quality and usefulness as good or very good. The number of arthrocenteses performed at our institution's primary care clinic increased. Discussion: We created a workshop to teach residents arthrocentesis and assessment tools with strong validity and reliability evidence. The workshop was well regarded by residents, who applied their arthrocentesis skills during patient care.

First report of CrpP prevalence in a South American country.

The presence of crpP was established in 201 Pseudomonas aeruginosa isolates from 9 Peruvian hospitals. The 76.6% (154/201) of the isolates presented the crpP gene. Overall, 123/201 (61.2%) isolates were non-susceptible to ciprofloxacin. The prevalence of crpP-possessing P. aeruginosa in Peru is higher than in other geographical areas.

A cell-type-specific alternative splicing regulator shapes synapse properties in a trans-synaptic manner.

The specification of synaptic properties is fundamental for the function of neuronal circuits. "Terminal selector" transcription factors coordinate terminal gene batteries that specify cell-type-specific properties. Moreover, pan-neuronal splicing regulators have been implicated in directing neuronal differentiation. However, the cellular logic of how splicing regulators instruct specific synaptic properties remains poorly understood. Here, we combine genome-wide mapping of mRNA targets and cell-type-specific loss-of-function studies to uncover the contribution of the RNA-binding protein SLM2 to hippocampal synapse specification. Focusing on pyramidal cells and somatostatin (SST)-positive GABAergic interneurons, we find that SLM2 preferentially binds and regulates alternative splicing of transcripts encoding synaptic proteins. In the absence of SLM2, neuronal populations exhibit normal intrinsic properties, but there are non-cell-autonomous synaptic phenotypes and associated defects in a hippocampus-dependent memory task. Thus, alternative splicing provides a critical layer of gene regulation that instructs specification of neuronal connectivity in a trans-synaptic manner.