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1.
Res Sq ; 2024 May 24.
Article in English | MEDLINE | ID: mdl-38826437

ABSTRACT

Despite genome-wide association studies of late-onset Alzheimer's disease (LOAD) having identified many genetic risk loci1-6, the underlying disease mechanisms remain largely unknown. Determining causal disease variants and their LOAD-relevant cellular phenotypes has been a challenge. Leveraging our approach for identifying functional GWAS risk variants showing allele-specific open chromatin (ASoC)7, we systematically identified putative causal LOAD risk variants in human induced pluripotent stem cells (iPSC)-derived neurons, astrocytes, and microglia (MG) and linked PICALM risk allele to a previously unappreciated MG-specific role of PICALM in lipid droplet (LD) accumulation. ASoC mapping uncovered functional risk variants for 26 LOAD risk loci, mostly MG-specific. At the MG-specific PICALM locus, the LOAD risk allele of rs10792832 reduced transcription factor (PU.1) binding and PICALM expression, impairing the uptake of amyloid beta (Aß) and myelin debris. Interestingly, MG with PICALM risk allele showed transcriptional enrichment of pathways for cholesterol synthesis and LD formation. Genetic and pharmacological perturbations of MG further established a causal link between the reduced PICALM expression, LD accumulation, and phagocytosis deficits. Our work elucidates the selective LOAD vulnerability in microglia for the PICALM locus through detrimental LD accumulation, providing a neurobiological basis that can be exploited for developing novel clinical interventions.

2.
Genet Med ; : 101174, 2024 Jun 03.
Article in English | MEDLINE | ID: mdl-38847193

ABSTRACT

PURPOSE: We identified two individuals with de novo variants in SREBF2 that disrupt a conserved site 1 protease (S1P) cleavage motif required for processing SREBP2 into its mature transcription factor. These individuals exhibit complex phenotypic manifestations that partially overlap with SREBP pathway-related disease phenotypes, but SREBF2-related disease has not been previously reported. Thus, we set out to assess the effects of SREBF2 variants on SREBP pathway activation. METHODS: We undertook ultrastructure and gene expression analyses using fibroblasts from an affected individual and utilized a fly model of lipid droplet formation to investigate the consequences of SREBF2 variants on SREBP pathway function. RESULTS: We observed reduced lipid droplet (LD) formation, endoplasmic reticulum expansion, accumulation of aberrant lysosomes, and deficits in SREBP2 target gene expression in fibroblasts from an affected individual, indicating that the SREBF2 variant inhibits SREBP pathway activation. Using our fly model, we discovered that SREBF2 variants fail to induce LD production and act in a dominant-negative manner, which can be rescued by overexpression of S1P. CONCLUSION: Taken together, these data reveal a mechanism by which SREBF2 pathogenic variants that disrupt the S1P cleavage motif cause disease via dominant-negative antagonism of S1P, limiting the cleavage of S1P targets, including SREBP1 and SREBP2.

3.
Circulation ; 2024 Jun 04.
Article in English | MEDLINE | ID: mdl-38832505

ABSTRACT

BACKGROUND: Cardiovascular disease and stroke are common and costly, and their prevalence is rising. Forecasts on the prevalence of risk factors and clinical events are crucial. METHODS: Using the 2015 to March 2020 National Health and Nutrition Examination Survey and 2015 to 2019 Medical Expenditure Panel Survey, we estimated trends in prevalence for cardiovascular risk factors based on adverse levels of Life's Essential 8 and clinical cardiovascular disease and stroke. We projected through 2050, overall and by age and race and ethnicity, accounting for changes in disease prevalence and demographics. RESULTS: We estimate that among adults, prevalence of hypertension will increase from 51.2% in 2020 to 61.0% in 2050. Diabetes (16.3% to 26.8%) and obesity (43.1% to 60.6%) will increase, whereas hypercholesterolemia will decline (45.8% to 24.0%). The prevalences of poor diet, inadequate physical activity, and smoking are estimated to improve over time, whereas inadequate sleep will worsen. Prevalences of coronary disease (7.8% to 9.2%), heart failure (2.7% to 3.8%), stroke (3.9% to 6.4%), atrial fibrillation (1.7% to 2.4%), and total cardiovascular disease (11.3% to 15.0%) will rise. Clinical CVD will affect 45 million adults, and CVD including hypertension will affect more than 184 million adults by 2050 (>61%). Similar trends are projected in children. Most adverse trends are projected to be worse among people identifying as American Indian/Alaska Native or multiracial, Black, or Hispanic. CONCLUSIONS: The prevalence of many cardiovascular risk factors and most established diseases will increase over the next 30 years. Clinical and public health interventions are needed to effectively manage, stem, and even reverse these adverse trends.

4.
Mol Ecol Resour ; : e13986, 2024 Jun 20.
Article in English | MEDLINE | ID: mdl-38899721

ABSTRACT

Terrestrial orchids are a group of genetically understudied, yet culturally and economically important plants. The Orchidinae tribe contains many species that produce edible tubers that are used for the production of traditional delicacies collectively called 'salep'. Overexploitation of wild orchids in the Eastern Mediterranean and Western Asia threatens to drive many of these species to extinction, but cost-effective tools for monitoring their trade are currently lacking. Here we present a custom bait kit for target enrichment and sequencing of 205 novel genetic markers that are tailored to phylogenomic applications in Orchidinae s.l. A subset of 31 markers capture genes putatively involved in the production of glucomannan, a water-soluble polysaccharide that gives salep its distinctive properties. We tested the kit on 73 taxa native to the area, demonstrating universally high locus recovery irrespective of species identity, that exceeds the total sequence length obtained with alternative kits currently available. Phylogenetic inference with concatenation and coalescent approaches was robust and showed high levels of support for most clades, including some which were previously unresolved. Resolution for hybridizing and recently radiated lineages remains difficult, but could be further improved by analysing multiple haplotypes and the non-exonic sequences captured by our kit, with the promise to shed new light on the evolution of enigmatic taxa with a complex speciation history. Offering a step-up from traditional barcoding and universal markers, the genome-wide custom loci targeted by Orchidinae-205 are a valuable new resource to study the evolution, systematics and trade of terrestrial orchids.

5.
Trends Mol Med ; 2024 May 15.
Article in English | MEDLINE | ID: mdl-38755043

ABSTRACT

In this opinion article, we discuss potential connections between sleep disturbances observed in Alzheimer's disease (AD) and Parkinson's disease (PD) and the dysregulation of lipids in the brain. Research using Drosophila has highlighted the role of glial-mediated lipid metabolism in sleep and diurnal rhythms. Relevant to AD, the formation of lipid droplets in glia, which occurs in response to elevated neuronal reactive oxygen species (ROS), is required for sleep. In disease models, this process is disrupted, arguing a connection to sleep dysregulation. Relevant to PD, the degradation of neuronally synthesized glucosylceramides by glia requires glucocerebrosidase (GBA, a PD-associated risk factor) and this regulates sleep. Loss of GBA in glia causes an accumulation of glucosylceramides and neurodegeneration. Overall, research primarily using Drosophila has highlighted how dysregulation of glial lipid metabolism may underlie sleep disturbances in neurodegenerative diseases.

6.
JAMA Oncol ; 10(6): 773-783, 2024 Jun 01.
Article in English | MEDLINE | ID: mdl-38780929

ABSTRACT

Importance: The association between body composition (BC) and cancer outcomes is complex and incompletely understood. Previous research in non-small-cell lung cancer (NSCLC) has been limited to small, single-institution studies and yielded promising, albeit heterogeneous, results. Objectives: To evaluate the association of BC with oncologic outcomes in patients receiving immunotherapy for advanced or metastatic NSCLC. Design, Setting, and Participants: This comprehensive multicohort analysis included clinical data from cohorts receiving treatment at the Dana-Farber Brigham Cancer Center (DFBCC) who received immunotherapy given alone or in combination with chemotherapy and prospectively collected data from the phase 1/2 Study 1108 and the chemotherapy arm of the phase 3 MYSTIC trial. Baseline and follow-up computed tomography (CT) scans were collected and analyzed using deep neural networks for automatic L3 slice selection and body compartment segmentation (skeletal muscle [SM], subcutaneous adipose tissue [SAT], and visceral adipose tissue). Outcomes were compared based on baseline BC measures or their change at the first follow-up scan. The data were analyzed between July 2022 and April 2023. Main Outcomes and Measures: Hazard ratios (HRs) for the association of BC measurements with overall survival (OS) and progression-free survival (PFS). Results: A total of 1791 patients (878 women [49%]) with NSCLC were analyzed, of whom 487 (27.2%) received chemoimmunotherapy at DFBCC (DFBCC-CIO), 825 (46.1%) received ICI monotherapy at DFBCC (DFBCC-IO), 222 (12.4%) were treated with durvalumab monotherapy on Study 1108, and 257 (14.3%) were treated with chemotherapy on MYSTIC; median (IQR) ages were 65 (58-74), 66 (57-71), 65 (26-87), and 63 (30-84) years, respectively. A loss in SM mass, as indicated by a change in the L3 SM area, was associated with worse oncologic outcome across patient groups (HR, 0.59 [95% CI, 0.43-0.81] and 0.61 [95% CI, 0.47-0.79] for OS and PFS, respectively, in DFBCC-CIO; HR, 0.74 [95% CI, 0.60-0.91] for OS in DFBCC-IO; HR, 0.46 [95% CI, 0.33-0.64] and 0.47 [95% CI, 0.34-0.64] for OS and PFS, respectively, in Study 1108; HR, 0.76 [95% CI, 0.61-0.96] for PFS in the MYSTIC trial). This association was most prominent among male patients, with a nonsignificant association among female patients in the MYSTIC trial and DFBCC-CIO cohorts on Kaplan-Meier analysis. An increase of more than 5% in SAT density, as quantified by the average CT attenuation in Hounsfield units of the SAT compartment, was associated with poorer OS in 3 patient cohorts (HR, 0.61 [95% CI, 0.43-0.86] for DFBCC-CIO; HR, 0.62 [95% CI, 0.49-0.79] for DFBCC-IO; and HR, 0.56 [95% CI, 0.40-0.77] for Study 1108). The change in SAT density was also associated with PFS for DFBCC-CIO (HR, 0.73; 95% CI, 0.54-0.97). This was primarily observed in female patients on Kaplan-Meier analysis. Conclusions and Relevance: The results of this multicohort study suggest that loss in SM mass during systemic therapy for NSCLC is a marker of poor outcomes, especially in male patients. SAT density changes are also associated with prognosis, particularly in female patients. Automated CT-derived BC measurements should be considered in determining NSCLC prognosis.


Subject(s)
Body Composition , Carcinoma, Non-Small-Cell Lung , Immunotherapy , Lung Neoplasms , Humans , Carcinoma, Non-Small-Cell Lung/drug therapy , Carcinoma, Non-Small-Cell Lung/therapy , Carcinoma, Non-Small-Cell Lung/pathology , Lung Neoplasms/drug therapy , Lung Neoplasms/therapy , Lung Neoplasms/pathology , Lung Neoplasms/mortality , Female , Male , Immunotherapy/methods , Middle Aged , Aged , Progression-Free Survival , Adult
8.
Science ; 384(6697): 785-792, 2024 May 17.
Article in English | MEDLINE | ID: mdl-38753784

ABSTRACT

In response to excessive DNA damage, human cells can activate p53 to induce apoptosis. Cells lacking p53 can still undergo apoptosis upon DNA damage, yet the responsible pathways are unknown. We observed that p53-independent apoptosis in response to DNA damage coincided with translation inhibition, which was characterized by ribosome stalling on rare leucine-encoding UUA codons and globally curtailed translation initiation. A genetic screen identified the transfer RNAse SLFN11 and the kinase GCN2 as factors required for UUA stalling and global translation inhibition, respectively. Stalled ribosomes activated a ribotoxic stress signal conveyed by the ribosome sensor ZAKα to the apoptosis machinery. These results provide an explanation for the frequent inactivation of SLFN11 in chemotherapy-unresponsive tumors and highlight ribosome stalling as a signaling event affecting cell fate in response to DNA damage.


Subject(s)
Apoptosis , DNA Damage , Protein Biosynthesis , Ribosomes , Tumor Suppressor Protein p53 , Humans , Cell Line, Tumor , Codon/genetics , Leucine/genetics , Nuclear Proteins/genetics , Nuclear Proteins/metabolism , Protein Serine-Threonine Kinases/metabolism , Protein Serine-Threonine Kinases/genetics , Ribosomes/metabolism , Signal Transduction , Tumor Suppressor Protein p53/metabolism , Tumor Suppressor Protein p53/genetics , MAP Kinase Kinase Kinases/genetics , MAP Kinase Kinase Kinases/metabolism
9.
Antioxidants (Basel) ; 13(5)2024 Apr 24.
Article in English | MEDLINE | ID: mdl-38790613

ABSTRACT

Microtubule-associated protein Tau (MAPT) is strongly associated with the development of neurodegenerative diseases. In addition to driving the formation of neurofibrillary tangles (NFT), mutations in the MAPT gene can also cause oxidative stress through hyperpolarisation of the mitochondria. This study explores the impact that MAPT mutation is having on phospholipid metabolism in iPSC-derived dopamine neurons, and to determine if these effects are exacerbated by mitochondrial and endoplasmic reticulum stress. Neurons that possessed a mutated copy of MAPT were shown to have significantly higher levels of oxo-phospholipids (Oxo-PL) than wild-type neurons. Oxidation of the hydrophobic fatty acid side chains changes the chemistry of the phospholipid leading to disruption of membrane function and potential cell lysis. In wild-type neurons, both mitochondrial and endoplasmic reticulum stress increased Oxo-PL abundance; however, in MAPT mutant neurons mitochondrial stress appeared to have a minimal effect. Endoplasmic reticulum stress, surprisingly, reduced the abundance of Oxo-PL in MAPT mutant dopamine neurons, and we postulate that this reduction could be modulated through hyperactivation of the unfolded protein response and X-box binding protein 1. Overall, the results of this study contribute to furthering our understanding of the regulation and impact of oxidative stress in Parkinson's disease pathology.

10.
J Alzheimers Dis ; 99(4): 1473-1484, 2024.
Article in English | MEDLINE | ID: mdl-38820017

ABSTRACT

Background: Loneliness has been declared an "epidemic" associated with negative physical, mental, and cognitive health outcomes such as increased dementia risk. Less is known about the relationship between loneliness and advanced neuroimaging correlates of Alzheimer's disease (AD). Objective: To assess whether loneliness was associated with advanced neuroimaging markers of AD using neuroimaging data from Framingham Heart Study (FHS) participants without dementia. Methods: In this cross-sectional observational analysis, we used functional connectivity MRI (fcMRI), amyloid-ß (Aß) PET, and tau PET imaging data collected between 2016 and 2019 on eligible FHS cohort participants. Loneliness was defined as feeling lonely at least one day in the past week. The primary fcMRI marker was Default Mode Network intra-network connectivity. The primary PET imaging markers were Aß deposition in precuneal and FLR (frontal, lateral parietal and lateral temporal, retrosplenial) regions, and tau deposition in the amygdala, entorhinal, and rhinal regions. Results: Of 381 participants (mean age 58 [SD 10]) who met inclusion criteria for fcMRI analysis, 5% were classified as lonely (17/381). No association was observed between loneliness status and network changes. Of 424 participants (mean age 58 [SD = 10]) meeting inclusion criteria for PET analyses, 5% (21/424) were lonely; no associations were observed between loneliness and either Aß or tau deposition in primary regions of interest. Conclusions: In this cross-sectional study, there were no observable associations between loneliness and select fcMRI, Aß PET, and tau PET neuroimaging markers of AD risk. These findings merit further investigation in prospective studies of community-based cohorts.


Subject(s)
Alzheimer Disease , Amyloid beta-Peptides , Loneliness , Magnetic Resonance Imaging , Positron-Emission Tomography , tau Proteins , Humans , Alzheimer Disease/diagnostic imaging , Alzheimer Disease/metabolism , Alzheimer Disease/psychology , Male , Female , Amyloid beta-Peptides/metabolism , Cross-Sectional Studies , tau Proteins/metabolism , Loneliness/psychology , Middle Aged , Aged , Brain/diagnostic imaging , Brain/metabolism , Biomarkers , Neuroimaging
11.
Surg Infect (Larchmt) ; 25(4): 332-334, 2024 May.
Article in English | MEDLINE | ID: mdl-38696668

ABSTRACT

Background: Lactococcus species are used to ferment milk to yogurt, cheese, and other products. The gram-positive coccus causes diseases in amphibia and fish and is a rare human pathogen. Patients and Methods: A 51-year-old male underwent laparoscopic cholecystectomy for acute and chronic calculous cholecystitis. Lactococcus lactis was isolated from pus from his gallbladder empyema. Results: Our institutional database was searched for other cases of Lactococcus spp. infections and four patients (2 males, 2 females; aged 51, 64, 78, and 80 years) were identified during a four-year period. The three other patients had positive blood cultures associated with pneumonia, toxic megacolon, and severe gastroenteritis. All isolates were monocultures with Lactococcus lactis (2), Lactococcus garvieae (1) and Lactococcus raffinolactis (1). Two patients died related to their sepsis. We report the second case of cholecystitis involving Lactococcus. Conclusions: Lactococcus is a very rare pathogen mainly causing blood stream infections but needs to be considered to cause serious surgical infections in humans.


Subject(s)
Cholecystitis, Acute , Gram-Positive Bacterial Infections , Lactococcus lactis , Lactococcus , Humans , Male , Middle Aged , Lactococcus lactis/isolation & purification , Lactococcus/isolation & purification , Cholecystitis, Acute/microbiology , Cholecystitis, Acute/surgery , Female , Aged, 80 and over , Aged , Gram-Positive Bacterial Infections/microbiology , Gram-Positive Bacterial Infections/diagnosis , Cholecystectomy, Laparoscopic
12.
Med Phys ; 2024 May 07.
Article in English | MEDLINE | ID: mdl-38713916

ABSTRACT

BACKGROUND: Disease or injury may cause a change in the biomechanical properties of the lungs, which can alter lung function. Image registration can be used to measure lung ventilation and quantify volume change, which can be a useful diagnostic aid. However, lung registration is a challenging problem because of the variation in deformation along the lungs, sliding motion of the lungs along the ribs, and change in density. PURPOSE: Landmark correspondences have been used to make deformable image registration robust to large displacements. METHODS: To tackle the challenging task of intra-patient lung computed tomography (CT) registration, we extend the landmark correspondence prediction model deep convolutional neural network-Match by introducing a soft mask loss term to encourage landmark correspondences in specific regions and avoid the use of a mask during inference. To produce realistic deformations to train the landmark correspondence model, we use data-driven synthetic transformations. We study the influence of these learned landmark correspondences on lung CT registration by integrating them into intensity-based registration as a distance-based penalty. RESULTS: Our results on the public thoracic CT dataset COPDgene show that using learned landmark correspondences as a soft constraint can reduce median registration error from approximately 5.46 to 4.08 mm compared to standard intensity-based registration, in the absence of lung masks. CONCLUSIONS: We show that using landmark correspondences results in minor improvements in local alignment, while significantly improving global alignment.

13.
Brain Commun ; 6(3): fcae129, 2024.
Article in English | MEDLINE | ID: mdl-38707712

ABSTRACT

Stroke is the leading cause of long-term disability worldwide. Incurred brain damage can disrupt cognition, often with persisting deficits in language and executive capacities. Yet, despite their clinical relevance, the commonalities and differences between language versus executive control impairments remain under-specified. To fill this gap, we tailored a Bayesian hierarchical modelling solution in a largest-of-its-kind cohort (1080 patients with stroke) to deconvolve language and executive control with respect to the stroke topology. Cognitive function was assessed with a rich neuropsychological test battery including global cognitive function (tested with the Mini-Mental State Exam), language (assessed with a picture naming task), executive speech function (tested with verbal fluency tasks), executive control functions (Trail Making Test and Digit Symbol Coding Task), visuospatial functioning (Rey Complex Figure), as well as verbal learning and memory function (Soul Verbal Learning). Bayesian modelling predicted interindividual differences in eight cognitive outcome scores three months after stroke based on specific tissue lesion topologies. A multivariate factor analysis extracted four distinct cognitive factors that distinguish left- and right-hemispheric contributions to ischaemic tissue lesions. These factors were labelled according to the neuropsychological tests that had the strongest factor loadings: One factor delineated language and general cognitive performance and was mainly associated with damage to left-hemispheric brain regions in the frontal and temporal cortex. A factor for executive control summarized mental flexibility, task switching and visual-constructional abilities. This factor was strongly related to right-hemispheric brain damage of posterior regions in the occipital cortex. The interplay of language and executive control was reflected in two distinct factors that were labelled as executive speech functions and verbal memory. Impairments on both factors were mainly linked to left-hemispheric lesions. These findings shed light onto the causal implications of hemispheric specialization for cognition; and make steps towards subgroup-specific treatment protocols after stroke.

14.
PLoS One ; 19(5): e0298116, 2024.
Article in English | MEDLINE | ID: mdl-38722850

ABSTRACT

Spatial navigation is a multi-faceted behaviour drawing on many different aspects of cognition. Visuospatial abilities, such as mental rotation and visuospatial working memory, in particular, may be key factors. A range of tests have been developed to assess visuospatial processing and memory, but how such tests relate to navigation ability remains unclear. This understanding is important to advance tests of navigation for disease monitoring in various disorders (e.g., Alzheimer's disease) where spatial impairment is an early symptom. Here, we report the use of an established mobile gaming app, Sea Hero Quest (SHQ), as a measure of navigation ability in a sample of young, predominantly female university students (N = 78; 20; female = 74.3%; mean age = 20.33 years). We used three separate tests of navigation embedded in SHQ: wayfinding, path integration and spatial memory in a radial arm maze. In the same participants, we also collected measures of mental rotation (Mental Rotation Test), visuospatial processing (Design Organization Test) and visuospatial working memory (Digital Corsi). We found few strong correlations across our measures. Being good at wayfinding in a virtual navigation test does not mean an individual will also be good at path integration, have a superior memory in a radial arm maze, or rate themself as having a strong sense of direction. However, we observed that participants who were good in the wayfinding task of SHQ tended to perform well on the three visuospatial tasks examined here, and to also use a landmark strategy in the radial maze task. These findings help clarify the associations between different abilities involved in spatial navigation.


Subject(s)
Spatial Navigation , Humans , Female , Spatial Navigation/physiology , Male , Young Adult , Adult , Memory, Short-Term/physiology , Spatial Memory/physiology , Maze Learning/physiology , Space Perception/physiology , Adolescent , Mobile Applications
15.
Int J Stroke ; : 17474930241252530, 2024 Jun 02.
Article in English | MEDLINE | ID: mdl-38651756

ABSTRACT

BACKGROUND: Post-stroke cognitive impairment (PSCI) occurs in up to 50% of stroke survivors. Presence of pre-existing vascular brain injury, in particular the extent of white matter hyperintensities (WMH), is associated with worse cognitive outcome after stroke, but the role of WMH location in this association is unclear. AIMS: We determined if WMH in strategic white matter tracts explain cognitive performance after stroke. METHODS: Individual patient data from nine ischemic stroke cohorts with magnetic resonance imaging (MRI) were harmonized through the Meta VCI Map consortium. The association between WMH volumes in strategic tracts and domain-specific cognitive functioning (attention and executive functioning, information processing speed, language and verbal memory) was assessed using linear mixed models and lasso regression. We used a hypothesis-driven design, primarily addressing four white matter tracts known to be strategic in memory clinic patients: the left and right anterior thalamic radiation, forceps major, and left inferior fronto-occipital fasciculus. RESULTS: The total study sample consisted of 1568 patients (39.9% female, mean age = 67.3 years). Total WMH volume was strongly related to cognitive performance on all four cognitive domains. WMH volume in the left anterior thalamic radiation was significantly associated with cognitive performance on attention and executive functioning and information processing speed and WMH volume in the forceps major with information processing speed. The multivariable lasso regression showed that these associations were independent of age, sex, education, and total infarct volume and had larger coefficients than total WMH volume. CONCLUSION: These results show tract-specific relations between WMH volume and cognitive performance after ischemic stroke, independent of total WMH volume. This implies that the concept of strategic lesions in PSCI extends beyond acute infarcts and also involves pre-existing WMH. DATA ACCESS STATEMENT: The Meta VCI Map consortium is dedicated to data sharing, following our guidelines.

16.
Nat Commun ; 15(1): 3326, 2024 Apr 18.
Article in English | MEDLINE | ID: mdl-38637532

ABSTRACT

Cdk8 in Drosophila is the orthologue of vertebrate CDK8 and CDK19. These proteins have been shown to modulate transcriptional control by RNA polymerase II. We found that neuronal loss of Cdk8 severely reduces fly lifespan and causes bang sensitivity. Remarkably, these defects can be rescued by expression of human CDK19, found in the cytoplasm of neurons, suggesting a non-nuclear function of CDK19/Cdk8. Here we show that Cdk8 plays a critical role in the cytoplasm, with its loss causing elongated mitochondria in both muscles and neurons. We find that endogenous GFP-tagged Cdk8 can be found in both the cytoplasm and nucleus. We show that Cdk8 promotes the phosphorylation of Drp1 at S616, a protein required for mitochondrial fission. Interestingly, Pink1, a mitochondrial kinase implicated in Parkinson's disease, also phosphorylates Drp1 at the same residue. Indeed, overexpression of Cdk8 significantly suppresses the phenotypes observed in flies with low levels of Pink1, including elevated levels of ROS, mitochondrial dysmorphology, and behavioral defects. In summary, we propose that Pink1 and Cdk8 perform similar functions to promote Drp1-mediated fission.


Subject(s)
Drosophila Proteins , Drosophila , Animals , Humans , Phosphorylation , Drosophila/metabolism , Drosophila melanogaster/genetics , Drosophila melanogaster/metabolism , Drosophila Proteins/genetics , Drosophila Proteins/metabolism , Mitochondrial Dynamics/genetics , Cyclin-Dependent Kinases/genetics , Cyclin-Dependent Kinases/metabolism , Cyclin-Dependent Kinase 8/genetics , Cyclin-Dependent Kinase 8/metabolism
17.
bioRxiv ; 2024 Mar 13.
Article in English | MEDLINE | ID: mdl-38559164

ABSTRACT

Peripheral tissues become disrupted in Alzheimer's Disease (AD). However, a comprehensive understanding of how the expression of AD-associated toxic proteins, Aß42 and Tau, in neurons impacts the periphery is lacking. Using Drosophila, a prime model organism for studying aging and neurodegeneration, we generated the Alzheimer's Disease Fly Cell Atlas (AD-FCA): whole-organism single-nucleus transcriptomes of 219 cell types from adult flies neuronally expressing human Aß42 or Tau. In-depth analyses and functional data reveal impacts on peripheral sensory neurons by Aß42 and on various non-neuronal peripheral tissues by Tau, including the gut, fat body, and reproductive system. This novel AD atlas provides valuable insights into potential biomarkers and the intricate interplay between the nervous system and peripheral tissues in response to AD-associated proteins.

18.
J Neurochem ; 2024 Apr 20.
Article in English | MEDLINE | ID: mdl-38641924

ABSTRACT

Glucocerebrosidase 1 (GBA1) mutations are the most important genetic risk factors for Parkinson's disease (PD). Clinically, mild (e.g., p.N370S) and severe (e.g., p.L444P and p.D409H) GBA1 mutations have different PD phenotypes, with differences in age at disease onset, progression, and the severity of motor and non-motor symptoms. We hypothesize that GBA1 mutations cause the accumulation of α-synuclein by affecting the cross-talk between cellular protein degradation mechanisms, leading to neurodegeneration. Accordingly, we tested whether mild and severe GBA1 mutations differentially affect the degradation of α-synuclein via the ubiquitin-proteasome system (UPS), chaperone-mediated autophagy (CMA), and macroautophagy and differentially cause accumulation and/or release of α-synuclein. Our results demonstrate that endoplasmic reticulum (ER) stress and total ubiquitination rates were significantly increased in cells with severe GBA1 mutations. CMA was found to be defective in induced pluripotent stem cell (iPSC)-derived dopaminergic neurons with mild GBA1 mutations, but not in those with severe GBA1 mutations. When examining macroautophagy, we observed reduced formation of autophagosomes in cells with the N370S and D409H GBA1 mutations and impairments in autophagosome-lysosome fusion in cells with the L444P GBA1 mutation. Accordingly, severe GBA1 mutations were found to trigger the accumulation and release of oligomeric α-synuclein in iPSC-derived dopaminergic neurons, primarily as a result of increased ER stress and defective macroautophagy, while mild GBA1 mutations affected CMA, which is mainly responsible for the degradation of the monomeric form of α-synuclein. Overall, our findings provide new insight into the molecular basis of the clinical variability in PD associated with different GBA1 mutations.

19.
Fitoterapia ; 175: 105932, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38565380

ABSTRACT

Roots of Gentiana purpurea are known to have an intense bitter taste due to its high content of secoiridoids. In folk medicine roots have commonly been prepared as water decoctions, soaked in ethanol, or boiled with milk, wine, or beer. The aim of this study was to explore how various historical preparation methods influence yields of major bitter compounds in G. purpurea. HPLC-DAD analysis revealed that maceration with 40% and 70% ethanol, boiling with acetic acid (3% and 6%), vinegar and raw milk gave the highest extraction yields of gentiopicrin. Erythrocentaurin was detected when the roots were added to cold water before boiling, possibly because of enzymatic degradation. In contrast, erythrocentaurin was not detected in preparations where roots were added to boiling water, or when they were extracted with acetic acid or alcohol. The results stress the significance of traditional preparation methods to optimize yield of bioactive compounds.


Subject(s)
Gentiana , Plant Roots , Gentiana/chemistry , Plant Roots/chemistry , Taste , Iridoid Glucosides/isolation & purification , Chromatography, High Pressure Liquid , Phytochemicals/isolation & purification , Acetic Acid , Medicine, Traditional
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