-
Science Immunology Dec 2023Germinal centers (GCs) or analogous secondary lymphoid microstructures (SLMs) are thought to have evolved in endothermic species. However, living representatives of...
Germinal centers (GCs) or analogous secondary lymphoid microstructures (SLMs) are thought to have evolved in endothermic species. However, living representatives of their ectothermic ancestors can mount potent secondary antibody responses upon infection or immunization, despite the apparent lack of SLMs in these cold-blooded vertebrates. How and where adaptive immune responses are induced in ectothermic species in the absence of GCs or analogous SLMs remain poorly understood. Here, we infected a teleost fish (trout) with the parasite (Ich) and identified the formation of large aggregates of highly proliferating IgM B cells and CD4 T cells, contiguous to splenic melanomacrophage centers (MMCs). Most of these MMC-associated lymphoid aggregates (M-LAs) contained numerous antigen (Ag)-specific B cells. Analysis of the IgM heavy chain CDR3 repertoire of microdissected splenic M-LAs and non-M-LA areas revealed that the most frequent B cell clones induced after Ich infection were highly shared only within the M-LAs of infected animals. These M-LAs represented highly polyclonal SLMs in which Ag-specific B cell clonal expansion occurred. M-LA-associated B cells expressed high levels of activation-induced cytidine deaminase and underwent significant apoptosis, and somatic hypermutation of Igμ genes occurred prevalently in these cells. Our findings demonstrate that ectotherms evolved organized SLMs with GC-like roles. Moreover, our results also point to primordially conserved mechanisms by which M-LAs and mammalian polyclonal GCs develop and function.
Topics: Animals; Germinal Center; B-Lymphocytes; Immunoglobulin M; Antigens; Vertebrates; Mammals
PubMed: 37910630
DOI: 10.1126/sciimmunol.adf1627 -
Cell Stem Cell May 2024Frontotemporal dementia (FTD) is an incurable group of early-onset dementias that can be caused by the deposition of hyperphosphorylated tau in patient brains. However,...
Frontotemporal dementia (FTD) is an incurable group of early-onset dementias that can be caused by the deposition of hyperphosphorylated tau in patient brains. However, the mechanisms leading to neurodegeneration remain largely unknown. Here, we combined single-cell analyses of FTD patient brains with a stem cell culture and transplantation model of FTD. We identified disease phenotypes in FTD neurons carrying the MAPT-N279K mutation, which were related to oxidative stress, oxidative phosphorylation, and neuroinflammation with an upregulation of the inflammation-associated protein osteopontin (OPN). Human FTD neurons survived less and elicited an increased microglial response after transplantation into the mouse forebrain, which we further characterized by single nucleus RNA sequencing of microdissected grafts. Notably, downregulation of OPN in engrafted FTD neurons resulted in improved engraftment and reduced microglial infiltration, indicating an immune-modulatory role of OPN in patient neurons, which may represent a potential therapeutic target in FTD.
Topics: Osteopontin; Frontotemporal Dementia; Humans; Neurons; Animals; tau Proteins; Mice; Neuroinflammatory Diseases; Microglia; Mutation
PubMed: 38626772
DOI: 10.1016/j.stem.2024.03.013 -
Brain : a Journal of Neurology Sep 2023Amyotrophic lateral sclerosis is a progressive neurodegenerative disease that affects motor neurons in the spinal cord, brainstem and motor cortex, leading to paralysis...
Amyotrophic lateral sclerosis is a progressive neurodegenerative disease that affects motor neurons in the spinal cord, brainstem and motor cortex, leading to paralysis and eventually to death within 3-5 years of symptom onset. To date, no cure or effective therapy is available. The role of chronic endoplasmic reticulum stress in the pathophysiology of amyotrophic lateral sclerosis, as well as a potential drug target, has received increasing attention. Here, we investigated the mode of action and therapeutic effect of the endoplasmic reticulum-resident protein cerebral dopamine neurotrophic factor in three preclinical models of amyotrophic lateral sclerosis, exhibiting different disease development and aetiology: (i) the conditional choline acetyltransferase-tTA/TRE-hTDP43-M337V rat model previously described; (ii) the widely used SOD1-G93A mouse model; and (iii) a novel slow-progressive TDP43-M337V mouse model. To specifically analyse the endoplasmic reticulum stress response in motor neurons, we used three main methods: (i) primary cultures of motor neurons derived from embryonic Day 13 embryos; (ii) immunohistochemical analyses of spinal cord sections with choline acetyltransferase as spinal motor neuron marker; and (iii) quantitative polymerase chain reaction analyses of lumbar motor neurons isolated via laser microdissection. We show that intracerebroventricular administration of cerebral dopamine neurotrophic factor significantly halts the progression of the disease and improves motor behaviour in TDP43-M337V and SOD1-G93A rodent models of amyotrophic lateral sclerosis. Cerebral dopamine neurotrophic factor rescues motor neurons in vitro and in vivo from endoplasmic reticulum stress-associated cell death and its beneficial effect is independent of genetic disease aetiology. Notably, cerebral dopamine neurotrophic factor regulates the unfolded protein response initiated by transducers IRE1α, PERK and ATF6, thereby enhancing motor neuron survival. Thus, cerebral dopamine neurotrophic factor holds great promise for the design of new rational treatments for amyotrophic lateral sclerosis.
Topics: Animals; Mice; Rats; Amyotrophic Lateral Sclerosis; Choline O-Acetyltransferase; Dopamine; Endoplasmic Reticulum Stress; Endoribonucleases; Motor Neurons; Nerve Growth Factors; Neurodegenerative Diseases; Protein Serine-Threonine Kinases; Superoxide Dismutase-1; Disease Models, Animal
PubMed: 36928391
DOI: 10.1093/brain/awad087 -
Matrix Biology : Journal of the... Nov 2023Although abnormal TGFβ signaling is observed in several heritable forms of thoracic aortic aneurysms and dissections including Marfan syndrome, its precise role in...
Although abnormal TGFβ signaling is observed in several heritable forms of thoracic aortic aneurysms and dissections including Marfan syndrome, its precise role in aortic disease progression is still disputed. Using a mouse genetic approach and quantitative isobaric labeling proteomics, we sought to elucidate the role of TGFβ signaling in three Fbn1 mutant mouse models representing a range of aortic disease from microdissection (without aneurysm) to aneurysm (without rupture) to aneurysm and rupture. Results indicated that reduced TGFβ signaling and increased mast cell proteases were associated with microdissection. In contrast, increased abundance of extracellular matrix proteins, which could be reporters for positive TGFβ signaling, were associated with aneurysm. Marked reductions in collagens and fibrillins, and increased TGFβ signaling, were associated with aortic rupture. Our data indicate that TGFβ signaling performs context-dependent roles in the pathogenesis of thoracic aortic disease.
Topics: Humans; Aortic Aneurysm, Thoracic; Fibrillin-1; Fibrillins; Marfan Syndrome; Transforming Growth Factor beta
PubMed: 37683955
DOI: 10.1016/j.matbio.2023.09.001 -
Journal of Visualized Experiments : JoVE Nov 2023Pulmonary veins (PVs) are the major source of ectopic beats in atrial arrhythmias and play a crucial role in the development and progression of atrial fibrillation (AF)....
Pulmonary veins (PVs) are the major source of ectopic beats in atrial arrhythmias and play a crucial role in the development and progression of atrial fibrillation (AF). PVs contain myocardial sleeves (MS) composed of cardiomyocytes. MS are implicated in the initiation and maintenance of AF, as they preserve similarities to the cardiac working myocardium, including the ability to generate ectopic electrical impulses. Rodents are widely used and may represent excellent animal models to study the pulmonary vein myocardium since cardiomyocytes are widely present all over the vessel wall. However, precise microdissection and preparation of murine PVs is challenging due to the small organ size and intricate anatomy. We demonstrate a microscopy-guided microdissection protocol for isolating the murine left atrium (LA) together with the PVs. Immunofluorescence staining using cardiac Troponin-T (cTNT) and connexin 43 (Cx43) antibodies is performed to visualize the LA and PVs in full length. Imaging at 10x and 40x magnification provides a comprehensive view of the PV structure as well as detailed insights into the myocardial architecture, particularly highlighting the presence of connexin 43 within the MS.
Topics: Animals; Mice; Connexin 43; Pulmonary Veins; Microdissection; Myocardium; Atrial Fibrillation; Heart Atria; Fluorescent Antibody Technique; Catheter Ablation
PubMed: 38078615
DOI: 10.3791/65836 -
The Journal of Investigative Dermatology Jun 2024Human hair follicles (HFs) constitute a unique microbiota habitat that differs substantially from the skin surface. Traditional HF sampling methods fail to eliminate...
Human hair follicles (HFs) constitute a unique microbiota habitat that differs substantially from the skin surface. Traditional HF sampling methods fail to eliminate skin microbiota contaminants or assess the HF microbiota incompletely, and microbiota functions in human HF physiology remain ill explored. Therefore, we used laser-capture microdissection, metagenomic shotgun sequencing, and FISH to characterize the human scalp HF microbiota in defined anatomical compartments. This revealed significant compartment-, tissue lineage-, and donor age-dependent variations in microbiota composition. Greatest abundance variations between HF compartments were observed for viruses, archaea, Staphylococcus epidermidis, Cutibacterium acnes, and Malassezia restricta, with the latter 2 being the most abundant viable HF colonizers (as tested by propidium monoazide assay) and, surprisingly, most abundant in the HF mesenchyme. Transfection of organ-cultured human scalp HFs with S. epidermidis-specific lytic bacteriophages ex vivo downregulated transcription of genes known to regulate HF growth and development, metabolism, and melanogenesis, suggesting that selected microbial products may modulate HF functions. Indeed, HF treatment with butyrate, a metabolite of S. epidermidis and other HF microbiota, delayed catagen and promoted autophagy, mitochondrial activity, and gp100 and dermcidin expression ex vivo. Thus, human HF microbiota show spatial variations in abundance and modulate the physiology of their host, which invites therapeutic targeting.
Topics: Humans; Scalp; Microbiota; Hair Follicle; Adult; Staphylococcus epidermidis; Malassezia; Female; Middle Aged; Male; Aged; Propionibacteriaceae; Young Adult
PubMed: 38070726
DOI: 10.1016/j.jid.2023.11.006 -
Kidney International Reports Dec 2023Podocyte infolding glomerulopathy (PIG) is a newly recognized rare glomerular injury. The clinical significance and mechanism of this injury pattern remains unclear.
INTRODUCTION
Podocyte infolding glomerulopathy (PIG) is a newly recognized rare glomerular injury. The clinical significance and mechanism of this injury pattern remains unclear.
METHODS
We conducted a retrospective study of renal biopsies from January 2018 to December 2020 in Kingmed Diagnostics. The renal biopsy features and clinical data were reviewed. Laser scanning microdissection and mass spectrometry (LMD/MS) was conducted to analyze the potential mechanism.
RESULTS
A total of 116 (0.092%) out of 126,086 biopsies were diagnosed as PIG during the period. Of these, 89 (76.7%) cases were found to have PIG coexisting with immune-complex associated glomerulonephritis (IC-PIG) whereas 27 (23.3%) were identified as isolated PIG without immunoglobulin or complement deposition. Systemic lupus erythematosus (SLE), especially with membranous lupus nephritis (LN), was diagnosed in most (70.8%) IC-PIG cases. Of the isolated PIG cases, 51.9% had no known underlying conditions; however, a relatively high positive rate (42.1%) of antinuclear antibody (ANA) was detected. Nearly half (47.5%) of the patients presented with nephrotic syndrome (NS). PIG grade was associated with proteinuria in isolated PIG ( = 0.035). LMD/MS revealed dysregulated cytoskeletal protein α-actinin4 (ACTN4) and tubulin beta-4 chain in PIG compared with normal donor kidney and minimal change disease (MCD). The displacement of ACTN4 into the glomerular basement membrane (GBM) was confirmed by the confocal microscope.
CONCLUSION
PIG is a rare podocyte injury that can exist alone without underlying disease or be concurrent with various diseases, especially SLE. Podocyte cytoskeletal protein ACTN4 and tubulin beta-4 chain were dysregulated, which may be involved in the mechanism of PIG.
PubMed: 38106587
DOI: 10.1016/j.ekir.2023.09.014 -
Giornale Italiano Di Nefrologia :... Oct 2023Monoclonal Gammopathies of Renal Significance (MGRS) are a complex group of disorders characterized by the production of aberrant monoclonal proteins that interact with... (Review)
Review
Monoclonal Gammopathies of Renal Significance (MGRS) are a complex group of disorders characterized by the production of aberrant monoclonal proteins that interact with kidney structures, causing tissue damage. Unlike neoplastic forms, kidney damage in MGRS does not correlate with clone mass or circulating monoclonal protein levels, conferring unique pre-neoplastic or non-neoplastic properties to the responsible clones. This manuscript explores the heterogeneity of monoclonal proteins involved, varying from full immunoglobulins to free light chains (FLC), and how they result in a spectrum of kidney lesions with differing prognoses. We also elaborate on diagnostic challenges, emphasizing the indispensable role of kidney biopsy, including advanced techniques like laser microdissection and mass spectrometry (LMD/MS) for deposit characterization, particularly in ambiguous or complex cases. Clinical management and treatment considerations, including the necessity for clone identification, are also discussed.
Topics: Humans; Paraproteinemias; Kidney Diseases; Kidney; Immunoglobulin Light Chains; Antibodies, Monoclonal
PubMed: 38007837
DOI: No ID Found -
The World Journal of Men's Health Apr 2024Non-obstructive azoospermia (NOA) is a common, but complex problem, with multiple therapeutic options and a lack of clear guidelines. Hence, there is considerable...
Global Practice Patterns and Variations in the Medical and Surgical Management of Non-Obstructive Azoospermia: Results of a World-Wide Survey, Guidelines and Expert Recommendations.
PURPOSE
Non-obstructive azoospermia (NOA) is a common, but complex problem, with multiple therapeutic options and a lack of clear guidelines. Hence, there is considerable controversy and marked variation in the management of NOA. This survey evaluates contemporary global practices related to medical and surgical management for patients with NOA.
MATERIALS AND METHODS
A 56-question online survey covering various aspects of the evaluation and management of NOA was sent to specialists around the globe. This paper analyzes the results of the second half of the survey dealing with the management of NOA. Results have been compared to current guidelines, and expert recommendations have been provided using a Delphi process.
RESULTS
Participants from 49 countries submitted 336 valid responses. Hormonal therapy for 3 to 6 months was suggested before surgical sperm retrieval (SSR) by 29.6% and 23.6% of participants for normogonadotropic hypogonadism and hypergonadotropic hypogonadism respectively. The SSR rate was reported as 50.0% by 26.0% to 50.0% of participants. Interestingly, 46.0% reported successful SSR in <10% of men with Klinefelter syndrome and 41.3% routinely recommended preimplantation genetic testing. Varicocele repair prior to SSR is recommended by 57.7%. Half of the respondents (57.4%) reported using ultrasound to identify the most vascularized areas in the testis for SSR. One-third proceed directly to microdissection testicular sperm extraction (mTESE) in every case of NOA while others use a staged approach. After a failed conventional TESE, 23.8% wait for 3 months, while 33.1% wait for 6 months before proceeding to mTESE. The cut-off of follicle-stimulating hormone for positive SSR was reported to be 12-19 IU/mL by 22.5% of participants and 20-40 IU/mL by 27.8%, while 31.8% reported no upper limit.
CONCLUSIONS
This is the largest survey to date on the real-world medical and surgical management of NOA by reproductive experts. It demonstrates a diverse practice pattern and highlights the need for evidence-based international consensus guidelines.
PubMed: 38606867
DOI: 10.5534/wjmh.230339 -
Histopathology Jul 2024Deep learning holds immense potential for histopathology, automating tasks that are simple for expert pathologists and revealing novel biology for tasks that were...
AIMS
Deep learning holds immense potential for histopathology, automating tasks that are simple for expert pathologists and revealing novel biology for tasks that were previously considered difficult or impossible to solve by eye alone. However, the extent to which the visual strategies learned by deep learning models in histopathological analysis are trustworthy or not has yet to be systematically analysed. Here, we systematically evaluate deep neural networks (DNNs) trained for histopathological analysis in order to understand if their learned strategies are trustworthy or deceptive.
METHODS AND RESULTS
We trained a variety of DNNs on a novel data set of 221 whole-slide images (WSIs) from lung adenocarcinoma patients, and evaluated their effectiveness at (1) molecular profiling of KRAS versus EGFR mutations, (2) determining the primary tissue of a tumour and (3) tumour detection. While DNNs achieved above-chance performance on molecular profiling, they did so by exploiting correlations between histological subtypes and mutations, and failed to generalise to a challenging test set obtained through laser capture microdissection (LCM). In contrast, DNNs learned robust and trustworthy strategies for determining the primary tissue of a tumour as well as detecting and localising tumours in tissue.
CONCLUSIONS
Our work demonstrates that DNNs hold immense promise for aiding pathologists in analysing tissue. However, they are also capable of achieving seemingly strong performance by learning deceptive strategies that leverage spurious correlations, and are ultimately unsuitable for research or clinical work. The framework we propose for model evaluation and interpretation is an important step towards developing reliable automated systems for histopathological analysis.
Topics: Humans; Deep Learning; Lung Neoplasms; Adenocarcinoma of Lung; Neural Networks, Computer; Mutation
PubMed: 38556922
DOI: 10.1111/his.15180