Macrophage polarization in pathology Sica, Antonio; Erreni, Marco; Allavena, Paola ...
Cellular and Molecular Life Sciences,
11/2015, Volume:
72, Issue:
21
Journal Article, Book Review
Peer reviewed
Macrophages are cells of the innate immunity constituting the mononuclear phagocyte system and endowed with remarkable different roles essential for defense mechanisms, development of tissues, and ...homeostasis. They derive from hematopoietic precursors and since the early steps of fetal life populate peripheral tissues, a process continuing throughout adult life. Although present essentially in every organ/tissue, macrophages are more abundant in the gastro-intestinal tract, liver, spleen, upper airways, and brain. They have phagocytic and bactericidal activity and produce inflammatory cytokines that are important to drive adaptive immune responses. Macrophage functions are settled in response to microenvironmental signals, which drive the acquisition of polarized programs, whose extremes are simplified in the M1 and M2 dichotomy. Functional skewing of monocyte/macrophage polarization occurs in physiological conditions (e.g., ontogenesis and pregnancy), as well as in pathology (allergic and chronic inflammation, tissue repair, infection, and cancer) and is now considered a key determinant of disease development and/or regression. Here, we will review evidence supporting a dynamic skewing of macrophage functions in disease, which may provide a basis for macrophage-centered therapeutic strategies.
Inflammasome complexes function as key innate immune effectors that trigger inflammation in response to pathogen- and danger-associated signals. Here, we report that germline mutations in the ...inflammasome sensor NLRP1 cause two overlapping skin disorders: multiple self-healing palmoplantar carcinoma (MSPC) and familial keratosis lichenoides chronica (FKLC). We find that NLRP1 is the most prominent inflammasome sensor in human skin, and all pathogenic NLRP1 mutations are gain-of-function alleles that predispose to inflammasome activation. Mechanistically, NLRP1 mutations lead to increased self-oligomerization by disrupting the PYD and LRR domains, which are essential in maintaining NLRP1 as an inactive monomer. Primary keratinocytes from patients experience spontaneous inflammasome activation and paracrine IL-1 signaling, which is sufficient to cause skin inflammation and epidermal hyperplasia. Our findings establish a group of non-fever inflammasome disorders, uncover an unexpected auto-inhibitory function for the pyrin domain, and provide the first genetic evidence linking NLRP1 to skin inflammatory syndromes and skin cancer predisposition.
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•Germline, gain-of-function NLRP1 mutations cause MSPC and FKLC syndromes.•Mutant NLRP1 proteins have lower threshold for inflammasome activation.•The Pyrin (PYD) and LRR domains of NLRP1 inhibit its self-oligomerization.•NLRP1 mutants cause skin hyperplasia via paracrine inflammatory signaling.
Gain-of-function mutations in the inflammasome sensor NLRP1 increase susceptibility to skin cancer and unmask unique regulatory autoinhibition in the inflammasome.
As of August 23, 2020, the 2019 novel coronavirus disease (COVID-19) has infected more than 23,518,340 people and caused more than 810,492 deaths worldwide including 4,717 deaths in China. We present ...a case of a 53-year-old woman who was admitted to the hospital because of dry coughs and high fever on January 26, 2020, in Wuhan, China. She was not tested for SARS-CoV-2 RNA until on hospital day 11 (illness day 21) because of a significant shortage of test kits at the local hospital. Then, her test was positive for COVID-19 on hospital day 20. Despite intensive medical treatments, she developed respiratory failure with secondary bacterial infection and expired on hospital day 23 (3 days after she was tested positive for SARS-CoV-2 RNA). A systemic autopsy examination, including immunohistochemistry and ultrastructural studies, demonstrates that SARS-CoV-2 can infect multiple organs with profound adverse effect on the immune system, and the lung pathology is characterized by diffuse alveolar damage. Extrapulmonary SARS-CoV-2 RNA was detected in several organs postmortem. The detailed pathological features are described. In addition, this report highlights the value of forensic autopsy in studying SARS-CoV-2 infection and the importance of clinicopathological correlation in better understanding the pathogenesis of COVID-19.
Intermittent fasting (IF) protects against the development of metabolic diseases and cancer, but whether it can prevent diabetic microvascular complications is not known. In
mice, we examined the ...impact of long-term IF on diabetic retinopathy (DR). Despite no change in glycated hemoglobin,
mice on the IF regimen displayed significantly longer survival and a reduction in DR end points, including acellular capillaries and leukocyte infiltration. We hypothesized that IF-mediated changes in the gut microbiota would produce beneficial metabolites and prevent the development of DR. Microbiome analysis revealed increased levels of Firmicutes and decreased Bacteroidetes and Verrucomicrobia. Compared with
mice on ad libitum feeding, changes in the microbiome of the
mice on IF were associated with increases in gut mucin, goblet cell number, villi length, and reductions in plasma peptidoglycan. Consistent with the known modulatory effects of Firmicutes on bile acid (BA) metabolism, measurement of BAs demonstrated a significant increase of tauroursodeoxycholate (TUDCA), a neuroprotective BA, in
on IF but not in
on AL feeding. TGR5, the TUDCA receptor, was found in the retinal primary ganglion cells. Expression of TGR5 did not change with IF or diabetes. However, IF reduced retinal TNF-α mRNA, which is a downstream target of TGR5 activation. Pharmacological activation of TGR5 using INT-767 prevented DR in a second diabetic mouse model. These findings support the concept that IF prevents DR by restructuring the microbiota toward species producing TUDCA and subsequent retinal protection by TGR5 activation.
In October 2016, the American Association for Cancer Research held a meeting of international childhood cancer predisposition syndrome experts to evaluate the current knowledge of these syndromes and ...to propose consensus surveillance recommendations. Herein, we summarize clinical and genetic aspects of RASopathies and Sotos, Weaver, Rubinstein-Taybi, Schinzel-Giedion, and NKX2-1 syndromes as well as specific metabolic disorders known to be associated with increased childhood cancer risk. In addition, the expert panel reviewed whether sufficient data exist to make a recommendation that all patients with these disorders be offered cancer surveillance. For all syndromes, the panel recommends increased awareness and prompt assessment of clinical symptoms. Patients with Costello syndrome have the highest cancer risk, and cancer surveillance should be considered. Regular physical examinations and complete blood counts can be performed in infants with Noonan syndrome if specific
or
mutations are present, and in patients with CBL syndrome. Also, the high brain tumor risk in patients with L-2 hydroxyglutaric aciduria may warrant regular screening with brain MRIs. For most syndromes, surveillance may be needed for nonmalignant health problems.
Cutaneous clear cell proliferations encompass a heterogenous group of several primary cutaneous neoplasms and metastatic tumors with different histogenesis. Many of these clear cell proliferations ...may seem strikingly similar under the microscope resulting in challenging diagnosis. In many of these clear cell lesions, the reason for the clear or pale appearance of proliferating cells is unknown, whereas in other ones, this clear cell appearance is due to intracytoplasmic accumulation of glycogen, mucin, or lipid. Artifacts of tissue processing and degenerative phenomenon may also be responsible for the clear cell appearance of proliferating cells. Awareness of the histopathologic findings as well as histochemical and immunohistochemical techniques are crucial to the accurate diagnosis. This review details the histopathologic features of clear cell cutaneous proliferations, classifying them according their type of differentiation and paying special attention to the histopathologic differential diagnosis among them.
The immune microenvironment of hepatocellular carcinoma (HCC) is poorly characterized. Combining two single-cell RNA sequencing technologies, we produced transcriptomes of CD45+ immune cells for HCC ...patients from five immune-relevant sites: tumor, adjacent liver, hepatic lymph node (LN), blood, and ascites. A cluster of LAMP3+ dendritic cells (DCs) appeared to be the mature form of conventional DCs and possessed the potential to migrate from tumors to LNs. LAMP3+ DCs also expressed diverse immune-relevant ligands and exhibited potential to regulate multiple subtypes of lymphocytes. Of the macrophages in tumors that exhibited distinct transcriptional states, tumor-associated macrophages (TAMs) were associated with poor prognosis, and we established the inflammatory role of SLC40A1 and GPNMB in these cells. Further, myeloid and lymphoid cells in ascites were predominantly linked to tumor and blood origins, respectively. The dynamic properties of diverse CD45+ cell types revealed by this study add new dimensions to the immune landscape of HCC.
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•Two scRNA-seq platforms reveal a high-resolution dynamic immune landscape in HCC•LAMP3+ DCs, arising from cDCs, can migrate from tumors to hepatic lymph nodes•Paired ligand-receptor analyses implicate the regulation of lymphocytes by LAMP3+ DCs•Macrophage subsets in tumors show distinct states and potentials to egress to ascites
Integrated single-cell RNA sequencing technologies and bioinformatics approaches reveal a high-resolution immune landscape of hepatocellular carcinoma, identifying inflammatory signatures and functional states of myeloid cells as well as predictions of complex cell-cell interactions.
: A retrospective study was carried out on 100 randomly selected medico‐legal autopsies of victims who had committed suicide by hanging. All cases had undergone full police and coronial ...investigation. Complete external and internal examinations had been carried out including routine histological examination of organs. The age range of victims was 15–94 years (average, 41.7 years) with a male‐to‐female ratio of 7:1. External and internal injuries were consistent with the reported events. Diagnoses based purely on histology included hepatic steatosis (n = 16), asthma (n = 3), lymphocytic thyroiditis (n = 2), and pulmonary and cardiac sarcoidosis (n = 1). A large cell carcinoma of the lung and a rectal adenocarcinoma were confirmed. Histological evaluation was, however, of limited usefulness in contributing to the medico‐legal evaluation of cases, with careful scene, external and internal examinations providing the most relevant information. The results of histological examination of tissues were all incidental to the cause, mechanism, and manner of death.
Following ischemia, the blood–brain barrier is compromised in the peri-infarct zone leading to secondary injury and dysfunction that can limit recovery. Currently, it is uncertain what structural ...changes could account for blood–brain barrier permeability, particularly with aging. Here we examined the ultrastructure of early and delayed changes (3 versus 72 h) to the blood–brain barrier in young adult and aged mice (3–4 versus 18 months) subjected to photothrombotic stroke. At both time points and ages, permeability was associated with a striking increase in endothelial caveolae and vacuoles. Tight junctions were generally intact although small spaces were detected in a few cases. In young mice, ischemia led to a significant increase in pericyte process area and vessel coverage whereas these changes were attenuated with aging. Stroke led to an expansion of the basement membrane region that peaked at 3 h and partially recovered by 72 h in both age groups. Astrocyte endfeet and their mitochondria were severely swollen at both times points and ages. Our results suggest that blood–brain barrier permeability in young and aged animals is mediated by transcellular pathways (caveolae/vacuoles), rather than tight junction loss. Further, our data indicate that the effects of ischemia on pericytes and basement membrane are affected by aging.
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