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1.
Methods Mol Biol ; 2852: 181-196, 2025.
Article in English | MEDLINE | ID: mdl-39235745

ABSTRACT

This chapter introduces protocols for culturing and maintaining Dictyostelium discoideum and methods for conducting virulence assays in this organism to study bacterial pathogenicity. It outlines advanced techniques, such as automated microscopy and flow cytometry, for detailed cellular analysis and traditional microbiological approaches. These comprehensive protocols will enable researchers to probe the virulence factors of pathogens like Klebsiella pneumoniae and to elucidate the details of host-pathogen interactions within a cost-effective and adaptable laboratory framework.


Subject(s)
Dictyostelium , Flow Cytometry , Klebsiella pneumoniae , Dictyostelium/microbiology , Flow Cytometry/methods , Klebsiella pneumoniae/pathogenicity , Phagocytosis , Virulence , Host-Pathogen Interactions , Microscopy/methods
2.
Methods Mol Biol ; 2852: 171-179, 2025.
Article in English | MEDLINE | ID: mdl-39235744

ABSTRACT

Studying host-pathogen interactions is essential for understanding infectious diseases and developing possible treatments, especially for priority pathogens with increased virulence and antibiotic resistance, such as Klebsiella pneumoniae. Over time, this subject has been approached from different perspectives, often using mammal host models and invasive endpoint measurements (e.g., sacrifice and organ extraction). However, taking advantage of technological advances, it is now possible to follow the infective process by noninvasive visualization in real time, using optically amenable surrogate hosts. In this line, this chapter describes a live-cell imaging approach to monitor the interaction of K. pneumoniae and potentially other bacterial pathogens with zebrafish larvae in vivo. This methodology is based on the microinjection of fluorescent bacteria into the otic vesicle, followed by time-lapse observation by automated fluorescence microscopy with environmental control, monitoring the dynamics of immune cell recruitment, bacterial load, and larvae survival.


Subject(s)
Host-Pathogen Interactions , Klebsiella Infections , Klebsiella pneumoniae , Larva , Microinjections , Microscopy, Fluorescence , Zebrafish , Animals , Zebrafish/microbiology , Klebsiella pneumoniae/immunology , Microinjections/methods , Larva/microbiology , Larva/immunology , Microscopy, Fluorescence/methods , Host-Pathogen Interactions/immunology , Klebsiella Infections/microbiology , Klebsiella Infections/immunology , Disease Models, Animal
3.
Article in English | MEDLINE | ID: mdl-39255520

ABSTRACT

Heart rate variability (HRV) has shown potential as a tool for monitoring thermal strain, but there is limited data to support its efficacy in older adults during prolonged heat exposures. We compared HRV between young (19-31 years, n=20) and older (61-78 years, n=39) adults during 9 hours of heat exposure (40°C, 9% RH). We also explored whether heart rate (HR) and/or HRV could be used to distinguish older adults who achieved elevated thermal strain, defined as either 1) an increase in core temperature >1.0°C (occurring in 39% [15/39]) or 2) a reduction in systolic blood pressure >10 mm Hg (occurring in 67% [26/39]). Percentage of age-predicted maximal HR and percentage of heart rate reserve (HRR) were higher, whereas standard deviation of normal RR intervals (SDNN), the square root of the mean of squared differences between successive RR intervals (RMSSD), high frequency power (HF), and cardiac vagal index (CVI) were lower in older compared to young adults (P≤0.004) during heat exposure. In older adults, increases in core temperature were correlated with percentage of age-predicted maximal HR, percentage of HRR, RMSSD, and CVI (P≤0.031), whereas changes in systolic blood pressure were not significantly associated with HR or HRV indices (P≤0.327). Receiver operating characteristic curve analysis indicated that HR and HRV indices had generally poor ability to identify older adults with elevated thermal strain (area under the curve ≤0.65). Age-related differences in HRV, consistent with vagal withdrawal among older adults, remained during daylong heat exposure, but marked heterogeneity of response likely contributed to HRV providing limited discriminatory value in identifying changes in core temperature or blood pressure in older adults.

4.
Sci Rep ; 14(1): 20416, 2024 09 02.
Article in English | MEDLINE | ID: mdl-39223259

ABSTRACT

Autism spectrum disorders (ASD) are complex neurodevelopmental conditions characterized by impairments in social communication, repetitive behaviors, and restricted interests. Epigenetic modifications serve as critical regulators of gene expression playing a crucial role in controlling brain function and behavior. Lysine (K)-specific demethylase 6B (KDM6B), a stress-inducible H3K27me3 demethylase, has emerged as one of the highest ASD risk genes, but the precise effects of KDM6B mutations on neuronal activity and behavioral function remain elusive. Here we show the impact of KDM6B mosaic brain knockout on the manifestation of different autistic-like phenotypes including repetitive behaviors, social interaction, and significant cognitive deficits. Moreover, KDM6B mosaic knockout display abnormalities in hippocampal excitatory synaptic transmission decreasing NMDA receptor mediated synaptic transmission and plasticity. Understanding the intricate interplay between epigenetic modifications and neuronal function may provide novel insights into the pathophysiology of ASD and potentially inform the development of targeted therapeutic interventions.


Subject(s)
Autism Spectrum Disorder , Jumonji Domain-Containing Histone Demethylases , Mice, Knockout , Synaptic Transmission , Animals , Jumonji Domain-Containing Histone Demethylases/genetics , Jumonji Domain-Containing Histone Demethylases/metabolism , Synaptic Transmission/genetics , Autism Spectrum Disorder/genetics , Mice , Brain/metabolism , Neuronal Plasticity/genetics , Behavior, Animal , Hippocampus/metabolism , Epigenesis, Genetic , Male , Synapses/metabolism
5.
Animals (Basel) ; 14(17)2024 Sep 07.
Article in English | MEDLINE | ID: mdl-39272393

ABSTRACT

Emerging evidence in women supports the notion that pregnancy may reset disease resistance, thereby providing protection against subsequent adverse health outcomes, but this hypothesis has not been adequately explored in domestic dogs. Cranial cruciate ligament (CCL) rupture is a degenerative orthopedic disease that frequently affects pet dogs, and its risk has been associated with disruption of the reproductive hormone axis. Our research team is conducting a lifetime cohort study of purebred Rottweilers in North America that have lived 30% longer than breed-average. Detailed medical and reproductive histories of 33 nulliparous and 32 parous Rottweilers were generated from questionnaires and review of medical records. Interviews with owners of bitches in the nulliparous group served to limit selection bias, confirming that in no instance was the reason for nulliparity based upon the owner's suspicion that a bitch had a heightened risk for CCL rupture. The risk of CCL rupture associated with parity and other exposure variables was estimated using multivariate logistic regression. Overall, CCL rupture was diagnosed in 17 of 65 (26%) bitches. Median age at first litter and CCL rupture were 3.6 and 6.5 years, respectively. Compared to nulliparous, parous bitches had a significant 94% reduction in CCL rupture risk adjusted for duration of ovary exposure, overweight body condition, dietary pattern, habitual physical activity, and work/sport activity [ORadjusted (95% CI) = 0.06 (0.01-0.46); (p = 0.006)]. The observed parity-associated CCL rupture risk reduction remained robust in sensitivity analysis excluding six nulliparous bitches for which decision not to breed was based on diagnosis of hip or elbow dysplasia, conditions which may be genetically linked to CCL rupture [ORadjusted (95% CI) = 0.08 (0.01-0.58); (p = 0.01)]. This work sets the stage for replication studies in other canine populations that should begin to explore the mechanistic basis for parity-associated CCL rupture risk reduction and to pursue other non-reproductive health outcomes in bitches whose incidence or severity may be parity-sensitive.

6.
J Neurochem ; 2024 Sep 08.
Article in English | MEDLINE | ID: mdl-39245629

ABSTRACT

Depression is a disabling and highly prevalent psychiatric illness. Multiple studies have linked glutamatergic dysfunction with the pathophysiology of depression, but the exact alterations in the glutamatergic system that contribute to depressive-like behaviors are not fully understood. Recent evidence suggests that a decreased level in neuronal glutamate transporter (EAAT3), known to control glutamate levels and limit the activation of glutamate receptors at synaptic sites, may contribute to the manifestation of a depressive phenotype. Here, we tested the possibility that increased EAAT3 expression at excitatory synapses could reduce the susceptibility of mice to develop depressive-like behaviors when challenged to a 5-week unpredictable chronic mild stress (UCMS) protocol. Mice overexpressing EAAT3 in the forebrain (EAAT3glo/CMKII) and control littermates (EAAT3glo) were assessed for depressive-like behaviors and long-term memory performance after being subjected to UCMS conditions. We found that, after UCMS, EAAT3glo/CMKII mice did not exhibit depressive-like behaviors or memory alterations observed in control mice. Moreover, we found that EAAT3glo/CMKII mice did not show alterations in phasic dopamine release in the nucleus accumbens neither in long-term synaptic plasticity in the CA1 region of the hippocampus after UCMS, as observed in control littermates. Altogether these results suggest that forebrain EAAT3 overexpression may be related to a resilient phenotype, both at behavioral and functional level, to the deleterious effect of chronic stress, highlighting the importance of neuronal EAAT3 in the pathophysiology of depressive-like behaviors.

7.
Cureus ; 16(8): e67386, 2024 Aug.
Article in English | MEDLINE | ID: mdl-39310528

ABSTRACT

Paraproteinemias or monoclonal gammopathies constitute a broad spectrum of heterogeneous clonal disorders of plasma cells characterized by the secretion of monoclonal proteins of heavy or light chains and the development of symptoms associated with them through mechanisms independent of tumor burden. Specifically, peripheral neuropathies represent an increasingly recognized manifestation of these paraproteinemias. We report a case of a 71-year-old female who presented to the emergency department with clinical symptoms of perioral paresthesias associated with an ataxic gait that progressively compromised her functionality, eventually completely limiting her ability to walk. Initially diagnosed with chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS syndrome), management with corticosteroids was initiated, leading to partial improvement. After comprehensive etiological studies ruled out common causes of peripheral neuropathy (PN), a monoclonal peak of immunoglobulin M (IgM) was detected. With the initiation of appropriate treatment, the patient progressively regained her ability to walk. Unfortunately, due to prolonged corticosteroid use, she developed osteoporosis and multiple fragility fractures, which again limited her mobility. CLIPPERS syndrome coexisting with monoclonal gammopathy is extremely rare, highlighting the importance of this report.

8.
Cureus ; 16(7): e63896, 2024 Jul.
Article in English | MEDLINE | ID: mdl-39104966

ABSTRACT

There is a growing development of immunochromatographic tests for the detection of specific Plasmodium spp. antigens. These tests rely on capturing antigens from peripheral blood using monoclonal or polyclonal antibodies against specific targets. We present the case of a 28-year-old male patient with a history of two previous episodes of Plasmodium falciparum malaria, treated appropriately seven months and three years ago. He was referred to our institution with a six-day history of fever, epigastric pain, hematuria, and vomiting. Serial thick and thin blood smears were negative for hemoparasites, but a Bioline™ Malaria Ag P.f/Pan rapid test was positive for the Pan (pLDH) band. Given the clinical context and inability to visualize Plasmodium in blood smears, the positive pLDH band on the rapid malaria test was considered a possible false positive. Subsequent tests concluded that the patient was experiencing a cytomegalovirus (CMV) infection, which improved with supportive management, and he was discharged symptom-free. Malaria remains a major public health issue in tropical and subtropical regions. While rapid diagnostic tests are crucial for timely diagnosis, false positives due to cross-reactivity with other infections and conditions are reported. Our case highlights the potential for cross-reactivity with CMV infections, although direct evidence of active viral replication was not obtained. This phenomenon can lead to the overestimation of malaria cases and inappropriate treatment, underscoring the need for careful interpretation of rapid test results.

9.
Cureus ; 16(7): e64411, 2024 Jul.
Article in English | MEDLINE | ID: mdl-39130868

ABSTRACT

Hemophagocytic lymphohistiocytosis (HLH) is a rare but potentially life-threatening syndrome characterized by excessive immune activation and tissue inflammation. This case report describes the early diagnosis of HLH in an adult patient who initially presented with a febrile syndrome associated with low back pain. The patient, a 33-year-old male, exhibited bicytopenia, hepatosplenomegaly, and hyperferritinemia without a previous diagnosis of sickle cell disease (SCD). Diagnostic challenges arose due to the overlapping clinical manifestations of SCD and HLH and their uncommon association. However, timely recognition and intervention were achieved through comprehensive diagnostic evaluations, including a bone marrow biopsy. The patient was promptly started on an appropriate therapeutic regimen, which led to significant clinical improvement. This case underscores the importance of considering HLH in the differential diagnosis of adults presenting with hematologic abnormalities and systemic inflammation. Early diagnosis and treatment are critical to improving outcomes for patients with this complex and severe disorder.

10.
Ann Hepatol ; 29(5): 101530, 2024.
Article in English | MEDLINE | ID: mdl-39033929

ABSTRACT

INTRODUCTION AND OBJECTIVES: There are different situations in which an extrahepatic bile duct replacement or substitute is needed, such as initial and localized stages of bile duct cancer, agenesis, stenosis, or bile duct disruption. MATERIALS AND METHODS: A prosthesis obtained by electrospinning composed of Poly (D,L-lactide-co-glycolide) (PGLA) - Polycaprolactone (PCL) - Gelatin (Gel) was developed, mechanical and biological tests were carried out to evaluate resistance to tension, biocompatibility, biodegradability, cytotoxicity, morphological analysis and cell culture. The obtained prosthesis was placed in the extrahepatic bile duct of 15 pigs with a 2-year follow-up. Liver function tests and cholangioscopy were evaluated during follow-up. RESULTS: Mechanical and biological evaluations indicate that this scaffold is biocompatible and biodegradable. The prosthesis implanted in the experimental model allowed cell adhesion, migration, and proliferation, maintaining bile duct permeability without altering liver function tests. Immunohistochemical analysis indicates the presence of biliary epithelium. CONCLUSIONS: A tubular scaffold composed of electrospun PGLA-PCL-Gel nanofibers was used for the first time to replace the extrahepatic bile duct in pigs. Mechanical and biological evaluations indicate that this scaffold is biocompatible and biodegradable, making it an excellent candidate for use in bile ducts and potentially in other tissue engineering applications.


Subject(s)
Absorbable Implants , Bile Ducts, Extrahepatic , Gelatin , Polyesters , Tissue Engineering , Tissue Scaffolds , Animals , Bile Ducts, Extrahepatic/surgery , Tissue Engineering/methods , Swine , Materials Testing , Polylactic Acid-Polyglycolic Acid Copolymer/chemistry , Cell Proliferation , Prosthesis Design , Biocompatible Materials , Cell Movement , Cell Adhesion , Time Factors , Liver Function Tests , Nanofibers
11.
Molecules ; 29(13)2024 Jun 25.
Article in English | MEDLINE | ID: mdl-38998963

ABSTRACT

Solifenacin (SFC) is a potent muscarinic antagonist that effectively reduces bladder muscle contraction, thereby alleviating symptoms such as frequency of micturition and urgency. Oxidation of SFC leads to the formation of impurities like Impurity K. Effective analysis and control of this impurity is crucial for ensuring compliance with regulatory standards and safeguarding patient health. To address these challenges, we propose a novel one-step synthesis of Impurity K from SFC. Impurity K was synthesized using cerium(IV) ammonium nitrate (CAN) in water/acetonitrile as the solvent. Additionally, we describe a new HPLC-MS method for the detection of Impurity K in solifenacin succinate tablets.


Subject(s)
Solifenacin Succinate , Solifenacin Succinate/chemistry , Solifenacin Succinate/analysis , Chromatography, High Pressure Liquid/methods , Drug Contamination , Mass Spectrometry/methods , Cerium/chemistry , Muscarinic Antagonists/analysis , Muscarinic Antagonists/chemistry , Muscarinic Antagonists/chemical synthesis , Tablets , Acetonitriles/chemistry , Liquid Chromatography-Mass Spectrometry
12.
Am J Hematol ; 2024 Jul 17.
Article in English | MEDLINE | ID: mdl-39016111

ABSTRACT

Cytogenomic characterization is crucial for the classification and risk stratification of acute myeloid leukemia (AML), thereby facilitating therapeutic decision-making. We examined the clinical utility of optical genome mapping (OGM) in 159 AML patients (103 newly diagnosed and 56 refractory/relapsed), all of whom also underwent chromosomal banding analysis (CBA), fluorescence in situ hybridization, and targeted next-generation sequencing. OGM detected nearly all clinically relevant cytogenetic abnormalities that SCG identified with >99% sensitivity, provided the clonal burden was above 20%. OGM identified additional cytogenomic aberrations and/or provided information on fusion genes in 77 (48%) patients, including eight patients with normal karyotypes and four with failed karyotyping. The most common additional alterations identified by OGM included chromoanagenesis (n = 23), KMT2A partial tandem duplication (n = 11), rearrangements involving MECOM (n = 7), NUP98 (n = 2), KMT2A (n = 2), JAK2 (n = 2), and other gene fusions in 17 patients, with 10 showing novel fusion gene partners. OGM also pinpointed fusion genes in 17 (11%) patients where chromosomal rearrangements were concurrently detected by OGM and CBA. Overall, 24 (15%) aberrations were identified exclusively by OGM and had the potential to alter AML classification, risk stratification, and/or clinical trial eligibility. OGM emerges as a powerful tool for identifying fusion genes and detecting subtle or cryptic cytogenomic aberrations that may otherwise remain undetectable by CBA.

13.
bioRxiv ; 2024 Jun 20.
Article in English | MEDLINE | ID: mdl-38948781

ABSTRACT

Parkinson's Disease (PD) is the second most common neurodegenerative disorder. Mutations in leucine-rich repeat kinase 2 (LRRK2), a multi-domain protein containing both a kinase and a GTPase, are a leading cause of the familial form of PD. Pathogenic LRRK2 mutations increase LRRK2 kinase activity. While the bulk of LRRK2 is found in the cytosol, the protein associates with membranes where its Rab GTPase substrates are found, and under certain conditions, with microtubules. Integrative structural studies using single-particle cryo-electron microscopy (cryo-EM) and in situ cryo-electron tomography (cryo-ET) have revealed the architecture of microtubule-associated LRRK2 filaments, and that formation of these filaments requires LRRK2's kinase to be in the active-like conformation. However, whether LRRK2 can interact with and form filaments on microtubules in its autoinhibited state, where the kinase domain is in the inactive conformation and the N-terminal LRR domain covers the kinase active site, was not known. Using cryo-ET, we show that full-length LRRK2 can oligomerize on microtubules in its autoinhibited state. Both WT-LRRK2 and PD-linked LRRK2 mutants formed filaments on microtubules. While these filaments are stabilized by the same interfaces seen in the active-LRRK2 filaments, we observed a new interface involving the N-terminal repeats that were disordered in the active-LRRK2 filaments. The helical parameters of the autoinhibited-LRRK2 filaments are different from those reported for the active-LRRK2 filaments. Finally, the autoinhibited-LRRK2 filaments are shorter and less regular, suggesting they are less stable.

14.
Cureus ; 16(6): e61937, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38978888

ABSTRACT

Monoclonal gammopathy of undetermined significance (MGUS) is a premalignant condition characterized by monoclonal paraprotein production, with IgM and non-IgM variants. While IgM MGUS is often associated with lymphoid neoplasms, non-IgM MGUS can progress to multiple myeloma. Comorbidities include bone mineral density loss and renal complications, such as monoclonal gammopathy of renal significance (MGRS) and peripheral neuropathy. Cardiovascular risks are also elevated. Despite its significance, MGUS often goes undiagnosed due to its asymptomatic nature and overlap with age-related comorbidities. We present a case of IgM MGRS manifesting as rapidly progressive glomerulonephritis, highlighting the diagnostic challenges and clinical implications of MGUS-associated complications.

15.
Mol Ecol ; : e17458, 2024 Jul 06.
Article in English | MEDLINE | ID: mdl-38970414

ABSTRACT

Colour signals play pivotal roles in different communication systems, and the evolution of these characters has been associated with behavioural ecology, integumentary production processes and perceptual mechanisms of the species involved. Here, we present the first insight into the molecular and histological basis of skin colour polymorphism within a miniaturized species of pumpkin toadlet, potentially representing the lowest size threshold for colour polytypism in tetrapods. Brachycephalus actaeus exhibits a coloration ranging from cryptic green to conspicuous orange skin, and our findings suggest that colour morphs differ in their capability to be detected by potential predators. We also found that the distribution and abundance of chromatophores are variable in the different colour morphs. The expression pattern of coloration related genes was predominantly associated with melanin synthesis (including dct, edn1, mlana, oca2, pmel, slc24a5, tyrp1 and wnt9a). Up-regulation of melanin genes in grey, green and brown skin was associated with higher melanophore abundance than in orange skin, where xanthophores predominate. Our findings provide a significant foundation for comparing and understanding the diverse pathways that contribute to the evolution of pigment production in the skin of amphibians.

16.
Psychotherapy (Chic) ; 2024 Jul 29.
Article in English | MEDLINE | ID: mdl-39073368

ABSTRACT

Cultural humility is an oft-studied construct in psychotherapy and supervision and, as such, has multiple definitions and frameworks and is frequently contextualized as the organizing pillar of the multicultural orientation framework (MCO; alongside cultural comfort and cultural opportunities; Davis et al., 2018; Owen, 2013). Many definitions of cultural humility emphasize a high level of self-awareness, openness to feedback, empathy, and curiosity toward others' cultural experiences (Davis et al., 2018; Foronda et al., 2016; Hook et al., 2013; Zhang et al., 2022). Despite empirical evidence linking cultural humility processes, and MCO more generally, to indicators of successful psychotherapy and supervision (e.g., Davis et al., 2018; Wilcox, Drinane, et al., 2022), little guidance exists for how supervisors may assess and foster their supervisees' cultural humility. Drawing from the literature, we delineate what we see as effective pedagogy and assessment of the key ingredients of cultural humility and provide recommendations for how supervisors can use the supervisory relationship to cultivate in their supervisees each of the necessary ingredients. Given cultural humility's key role in the MCO framework, we discuss how the ingredients required for cultural humility lay the groundwork for cultural comfort and cultural opportunities. Supervision vignettes and additional resources for supervisors are included. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

17.
Am J Clin Pathol ; 2024 Jul 22.
Article in English | MEDLINE | ID: mdl-39037433

ABSTRACT

OBJECTIVES: Widely accepted standardized criteria for peripheral blood (PB) smear review do not exist. The aim of this study was to collect data regarding PB smear review practices across multiple institutions, with a focus on pathologist review. METHODS: A 23-question survey was developed by members of the Society for Hematopathology (SH) Education Committee and distributed to SH members. The survey included questions on practice environment and PB smear review practices, including trainee involvement. RESULTS: Of 725 members contacted, 137 (19%) completed the entire survey. Over half of practices examined 5 to 20 smears a day. All respondents reported using complete blood count/differential leukocyte count data and clinical history as part of smear review. The reported proportion of laboratory-initiated vs clinician-requested reviews varied across respondents. Clinician-requested smear reviews were more likely to be billed and issued as a separate pathology report. Glass slide review (as opposed to digital microscopy) was used by most respondents. All respondents affirmed that PB smear review is an essential component of pathology training programs. Numerous free-text comments were submitted by respondents regarding their own experiences with PB smear review and suggested improvements. CONCLUSIONS: This survey elucidated the spectrum of practice patterns for pathologist review of blood smears and identified potential areas for process improvement.

18.
Sci Rep ; 14(1): 16000, 2024 07 11.
Article in English | MEDLINE | ID: mdl-38987406

ABSTRACT

Genomic surveillance (GS) programmes were crucial in identifying and quantifying the mutating patterns of SARS-CoV-2 during the COVID-19 pandemic. In this work, we develop a Bayesian framework to quantify the relative transmissibility of different variants tailored for regions with limited GS. We use it to study the relative transmissibility of SARS-CoV-2 variants in Chile. Among the 3443 SARS-CoV-2 genomes collected between January and June 2021, where sampling was designed to be representative, the Gamma (P.1), Lambda (C.37), Alpha (B.1.1.7), B.1.1.348, and B.1.1 lineages were predominant. We found that Lambda and Gamma variants' reproduction numbers were 5% (95% CI: [1%, 14%]) and 16% (95% CI: [11%, 21%]) larger than Alpha's, respectively. Besides, we observed a systematic mutation enrichment in the Spike gene for all circulating variants, which strongly correlated with variants' transmissibility during the studied period (r = 0.93, p-value = 0.025). We also characterised the mutational signatures of local samples and their evolution over time and with the progress of vaccination, comparing them with those of samples collected in other regions worldwide. Altogether, our work provides a reliable method for quantifying variant transmissibility under subsampling and emphasises the importance of continuous genomic surveillance.


Subject(s)
Bayes Theorem , COVID-19 , Mutation , SARS-CoV-2 , Chile , Humans , SARS-CoV-2/genetics , SARS-CoV-2/isolation & purification , COVID-19/transmission , COVID-19/virology , COVID-19/epidemiology , Genome, Viral , Spike Glycoprotein, Coronavirus/genetics
19.
BMC Biol ; 22(1): 142, 2024 Jun 26.
Article in English | MEDLINE | ID: mdl-38926759

ABSTRACT

BACKGROUND: The VPS50 protein functions in synaptic and dense core vesicle acidification, and perturbations of VPS50 function produce behavioral changes in Caenorhabditis elegans. Patients with mutations in VPS50 show severe developmental delay and intellectual disability, characteristics that have been associated with autism spectrum disorders (ASDs). The mechanisms that link VPS50 mutations to ASD are unknown. RESULTS: To examine the role of VPS50 in mammalian brain function and behavior, we used the CRISPR/Cas9 system to generate knockouts of VPS50 in both cultured murine cortical neurons and living mice. In cultured neurons, KO of VPS50 did not affect the number of synaptic vesicles but did cause mislocalization of the V-ATPase V1 domain pump and impaired synaptic activity, likely as a consequence of defects in vesicle acidification and vesicle content. In mice, mosaic KO of VPS50 in the hippocampus altered synaptic transmission and plasticity and generated robust cognitive impairments. CONCLUSIONS: We propose that VPS50 functions as an accessory protein to aid the recruitment of the V-ATPase V1 domain to synaptic vesicles and in that way plays a crucial role in controlling synaptic vesicle acidification. Understanding the mechanisms controlling behaviors and synaptic function in ASD-associated mutations is pivotal for the development of targeted interventions, which may open new avenues for therapeutic strategies aimed at ASD and related conditions.


Subject(s)
Mice, Knockout , Synaptic Vesicles , Animals , Mice , Behavior, Animal/physiology , Brain/metabolism , Neurons/metabolism , Neurons/physiology , Synapses/metabolism , Synapses/physiology , Synaptic Transmission , Synaptic Vesicles/metabolism , Vacuolar Proton-Translocating ATPases/metabolism , Vacuolar Proton-Translocating ATPases/genetics , Vesicular Transport Proteins/genetics , Vesicular Transport Proteins/metabolism
20.
Biol Res ; 57(1): 40, 2024 Jun 18.
Article in English | MEDLINE | ID: mdl-38890753

ABSTRACT

BACKGROUND: The brain cortex is responsible for many higher-level cognitive functions. Disruptions during cortical development have long-lasting consequences on brain function and are associated with the etiology of brain disorders. We previously found that the protein tyrosine phosphatase receptor delta Ptprd, which is genetically associated with several human neurodevelopmental disorders, is essential to cortical brain development. Loss of Ptprd expression induced an aberrant increase of excitatory neurons in embryonic and neonatal mice by hyper-activating the pro-neurogenic receptors TrkB and PDGFRß in neural precursor cells. However, whether these alterations have long-lasting consequences in adulthood remains unknown. RESULTS: Here, we found that in Ptprd+/- or Ptprd-/- mice, the developmental increase of excitatory neurons persists through adulthood, affecting excitatory synaptic function in the medial prefrontal cortex. Likewise, heterozygosity or homozygosity for Ptprd also induced an increase of inhibitory cortical GABAergic neurons and impaired inhibitory synaptic transmission. Lastly, Ptprd+/- or Ptprd-/- mice displayed autistic-like behaviors and no learning and memory impairments or anxiety. CONCLUSIONS: These results indicate that loss of Ptprd has long-lasting effects on cortical neuron number and synaptic function that may aberrantly impact ASD-like behaviors.


Subject(s)
Autistic Disorder , Neurons , Receptor-Like Protein Tyrosine Phosphatases, Class 2 , Animals , Receptor-Like Protein Tyrosine Phosphatases, Class 2/metabolism , Receptor-Like Protein Tyrosine Phosphatases, Class 2/genetics , Mice , Autistic Disorder/genetics , Autistic Disorder/physiopathology , Disease Models, Animal , Male , Cerebral Cortex/metabolism , Mice, Knockout , Synaptic Transmission/physiology , Mice, Inbred C57BL , Female
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