Fluorescent Reporters, Imaging, and Artificial Intelligence Toolkits to Monitor and Quantify Autophagy, Heterophagy, and Lysosomal Trafficking Fluxes.

Lysosomal compartments control the clearance of cell-own material (autophagy) or of material that cells endocytose from the external environment (heterophagy) to warrant supply of nutrients, to eliminate macromolecules or parts of organelles present in excess, aged, or containing toxic material. Inherited or sporadic mutations in lysosomal proteins and enzymes may hamper their folding in the endoplasmic reticulum (ER) and their lysosomal transport via the Golgi compartment, resulting in lysosomal dysfunction and storage disorders. Defective cargo delivery to lysosomal compartments is harmful to cells and organs since it causes accumulation of toxic compounds and defective organellar homeostasis.

TMX4-driven LINC complex disassembly and asymmetric autophagy of the nuclear envelope upon acute ER stress.

The endoplasmic reticulum (ER) is an organelle of nucleated cells that produces proteins, lipids and oligosaccharides. ER volume and activity are increased upon induction of unfolded protein responses (UPR) and are reduced upon activation of ER-phagy programs. A specialized domain of the ER, the nuclear envelope (NE), protects the cell genome with two juxtaposed lipid bilayers, the inner and outer nuclear membranes (INM and ONM) separated by the perinuclear space (PNS).

Tracking unlabeled cancer cells imaged with low resolution in wide migration chambers via U-NET class-1 probability (pseudofluorescence).

Cell migration is a pivotal biological process, whose dysregulation is found in many diseases including inflammation and cancer. Advances in microscopy technologies allow now to study cell migration in vitro, within engineered microenvironments that resemble in vivo conditions. However, to capture an entire 3D migration chamber for extended periods of time and with high temporal resolution, images are generally acquired with low resolution, which poses a challenge for data analysis.

Subcapsular Sinus Macrophages Promote Melanoma Metastasis to the Sentinel Lymph Nodes via an IL1α-STAT3 Axis.

During melanoma metastasis, tumor cells originating in the skin migrate via lymphatic vessels to the sentinel lymph node (sLN). This process facilitates tumor cell spread across the body. Here, we characterized the innate inflammatory response to melanoma in the metastatic microenvironment of the sLN.

Apyrase-mediated amplification of secretory IgA promotes intestinal homeostasis.

Secretory immunoglobulin A (SIgA) interaction with commensal bacteria conditions microbiota composition and function. However, mechanisms regulating reciprocal control of microbiota and SIgA are not defined. Bacteria-derived adenosine triphosphate (ATP) limits T follicular helper (Tfh) cells in the Peyer's patches (PPs) via P2X7 receptor (P2X7R) and thereby SIgA generation.

ACE2-binding exposes the SARS-CoV-2 fusion peptide to broadly neutralizing coronavirus antibodies.

The coronavirus spike glycoprotein attaches to host receptors and mediates viral fusion. Using a broad screening approach, we isolated seven monoclonal antibodies (mAbs) that bind to all human-infecting coronavirus spike proteins from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immune donors. These mAbs recognize the fusion peptide and acquire affinity and breadth through somatic mutations.

CANCOL, a Computer-Assisted Annotation Tool to Facilitate Colocalization and Tracking of Immune Cells in Intravital Microscopy.

Two-photon intravital microscopy (2P-IVM) has become a widely used technique to study cell-to-cell interactions in living organisms. Four-dimensional imaging data obtained via 2P-IVM are classically analyzed by performing automated cell tracking, a procedure that computes the trajectories followed by each cell. However, technical artifacts, such as brightness shifts, the presence of autofluorescent objects, and channel crosstalking, affect the specificity of imaging channels for the cells of interest, thus hampering cell detection.

Tau Seeds in Extracellular Vesicles Induce Tau Accumulation in Degradative Organelles of Cells.

Clinical progression of tauopathies may result from transcellular propagation of pathogenic Tau seeds with the possible involvement of extracellular vesicles (EVs) as transport vectors. We established a cell model for investigating EV delivery of proteins, since the mechanism regulating EV cargo delivery to recipient cells is poorly understood. In our cell model, EVs are readily internalized and accumulate in degradative organelles (DOs).

Author Correction: Evaluation of cell metabolic adaptation in wound and tumour by Fluorescence Lifetime Imaging Microscopy.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Prophylactic Activity of Orally Administered FliD-Reactive Monoclonal SIgA Against Infection.

infection is one of the most common causes of bacterial gastroenteritis worldwide and a major global health threat due to the rapid development of antibiotic resistance. Currently, there are no vaccines approved to prevent campylobacteriosis, and rehydration is the main form of therapy. Secretory immunoglobulin A (SIgA) is the main antibody class found in mucous secretions, including human milk, and serves as the first line of defense for the gastrointestinal epithelium against enteric pathogens.

Deep learning approach for quantification of organelles and misfolded polypeptide delivery within degradative compartments.

Endolysosomal compartments maintain cellular fitness by clearing dysfunctional organelles and proteins from cells. Modulation of their activity offers therapeutic opportunities. Quantification of cargo delivery to and/or accumulation within endolysosomes is instrumental for characterizing lysosome-driven pathways at the molecular level and monitoring consequences of genetic or environmental modifications.

Evaluation of cell metabolic adaptation in wound and tumour by Fluorescence Lifetime Imaging Microscopy.

Acidic pH occurs in acute wounds progressing to healing as consequence of a cell metabolic adaptation in response to injury-induced tissue hypoperfusion. In tumours, high metabolic rate leads to acidosis affecting cancer progression. Acidic pH affects activities of remodelling cells in vitro.

ESCRT-III-driven piecemeal micro-ER-phagy remodels the ER during recovery from ER stress.

The endoplasmic reticulum (ER) produces about 40% of the nucleated cell's proteome. ER size and content in molecular chaperones increase upon physiologic and pathologic stresses on activation of unfolded protein responses (UPR). On stress resolution, the mammalian ER is remodeled to pre-stress, physiologic size and function on activation of the LC3-binding activity of the translocon component SEC62.

Design of polymeric nanocapsules to improve their lympho-targeting capacity.

To design lympho-targeted nanocarriers with the capacity to enhance the activity of associated drugs/antigens whose target is within the lymphatic system. : Inulin (INU)-based nanocapsules (NCs), negatively charged and positively charged chitosan NCs were prepared by the solvent displacement techniques. The NCs were produced in two sizes: small (70 nm) and medium (170-250 nm).

The macrophage tetraspan MS4A4A enhances dectin-1-dependent NK cell-mediated resistance to metastasis.

The plasma membrane tetraspan molecule MS4A4A is selectively expressed by macrophage-lineage cells, but its function is unknown. Here we report that MS4A4A was restricted to murine and human mononuclear phagocytes and was induced during monocyte-to-macrophage differentiation in the presence of interleukin 4 or dexamethasone. Human MS4A4A was co-expressed with M2/M2-like molecules in subsets of normal tissue-resident macrophages, infiltrating macrophages from inflamed synovium and tumor-associated macrophages.

Epigenetic Control of Mitochondrial Fission Enables Self-Renewal of Stem-like Tumor Cells in Human Prostate Cancer.

Cancer stem cells (CSCs) contribute to disease progression and treatment failure in human cancers. The balance among self-renewal, differentiation, and senescence determines the expansion or progressive exhaustion of CSCs. Targeting these processes might lead to novel anticancer therapies.

Imaging Cell Interaction in Tracheal Mucosa During Influenza Virus Infection Using Two-photon Intravital Microscopy.

The analysis of cell-cell or cell-pathogen interaction in vivo is an important tool to understand the dynamics of the immune response to infection. Two-photon intravital microscopy (2P-IVM) allows the observation of cell interactions in deep tissue in living animals, while minimizing the photobleaching generated during image acquisition. To date, different models for 2P-IVM of lymphoid and non-lymphoid organs have been described.

ER-to-lysosome-associated degradation of proteasome-resistant ATZ polymers occurs via receptor-mediated vesicular transport.

Maintenance of cellular proteostasis relies on efficient clearance of defective gene products. For misfolded secretory proteins, this involves dislocation from the endoplasmic reticulum (ER) into the cytosol followed by proteasomal degradation. However, polypeptide aggregation prevents cytosolic dislocation and instead activates ill-defined lysosomal catabolic pathways.

Maternal Immune Activation Delays Excitatory-to-Inhibitory Gamma-Aminobutyric Acid Switch in Offspring.

Background: The association between maternal infection and neurodevelopmental defects in progeny is well established, although the biological mechanisms and the pathogenic trajectories involved have not been defined.

Methods: Pregnant dams were injected intraperitoneally at gestational day 9 with polyinosinic:polycytidylic acid. Neuronal development was assessed by means of electrophysiological, optical, and biochemical analyses.

Adeno-associated virus-mediated CASQ2 delivery rescues phenotypic alterations in a patient-specific model of recessive catecholaminergic polymorphic ventricular tachycardia.

Catecholaminergic Polymorphic Ventricular Tachycardia type 2 (CPVT2) is a highly lethal recessive arrhythmogenic disease caused by mutations in the calsequestrin-2 (CASQ2) gene. We have previously demonstrated that viral transfer of the wild-type (WT) CASQ2 gene prevents the development of CPVT2 in a genetically induced mouse model of the disease homozygous carrier of the R33Q mutation. In the present study, we investigated the efficacy of the virally mediated gene therapy in cardiomyocytes (CMs) differentiated from induced pluripotent stem cells (iPSCs) obtained from a patient carrying the homozygous CASQ2-G112+5X mutation.

Humoral innate immunity at the crossroad between microbe and matrix recognition: The role of PTX3 in tissue damage.

Innate immunity is involved in regulating inflammatory and tissue repair responses to injury. In particular, humoral innate immunity plays functions related to wound clearance from tissue debris, and regulation of macrophage and stromal cell activities. PTX3, a component of humoral innate immunity, orchestrates tissue repair by interacting with plasminogen and fibrin.

Identification of human somatostatin receptor 2 domains involved in internalization and signaling in QGP-1 pancreatic neuroendocrine tumor cell line.

Somatostatin exerts inhibitory effects on hormone secretion and cell proliferation via five receptor subtypes (SST1-SST5), whose internalization is regulated by β-arrestins. The receptor domains involved in these effects have been only partially elucidated. The aim of the study is to characterize the molecular mechanism and determinants responsible for somatostatin receptor 2 internalization and signaling in pancreatic neuroendocrine QGP-1 cell line, focusing on the third intracellular loop and carboxyl terminal domains.

Tailored chemokine receptor modification improves homing of adoptive therapy T cells in a spontaneous tumor model.

In recent years, tumor Adoptive Cell Therapy (ACT), using administration of ex vivo-enhanced T cells from the cancer patient, has become a promising therapeutic strategy. However, efficient homing of the anti-tumoral T cells to the tumor or metastatic site still remains a substantial hurdle. Yet the tumor site itself attracts both tumor-promoting and anti-tumoral immune cell populations through the secretion of chemokines.

The Fractalkine-Receptor Axis Improves Human Colorectal Cancer Prognosis by Limiting Tumor Metastatic Dissemination.

Human colorectal cancer (CRC) is a frequent neoplasia in Western countries, and its metastatic progression is a major cause of cancer-related death. In search of specific molecules upregulated in CRC, with possible clinical relevance, we performed a differential gene-profiling analysis in surgery-derived CRC samples and adjacent uninvolved intestinal mucosa. The chemokine CX3CL1 and its specific receptor CX3CR1 were significantly upregulated in tumors.