Biology subjects

Kralova, J.

Publications and source records attributed to Kralova, J..

4 recordsLinked to original sources

bioRxiv2023

Murine classical monocyte subsets display distinct functions and fates

Monocytes are short-lived myeloid immune cells that arise from adult hematopoiesis and circulate for a short time in the blood. They comprise two main subsets, in mice defined as classical Ly6Chigh and non-classical Ly6Clow monocytes (CM, NCM). Recent fate mapping and transcriptomic analyses revealed that CM themselves are heterogeneous. Here, we report surface markers that allow segregation of murine GMP- and MDP-derived CM in the BM and blood. Functional characterization, including fate definition following adoptive cell transfer, established that GMP-Mo and MDP-Mo could equal rise to homeostatic CM progeny, such as NCM in blood and gut macrophages, but differentially seeded selected other tissues. Specifically, GMP-Mo and MDP-Mo gave rise to distinct interstitial lung macrophages, thus linking CM dichotomy to previously reported pulmonary macrophage heterogeneity. Collectively, we provide comprehensive evidence for the existence of two functionally distinct CM subsets in the mouse, which differentially contribute to peripheral tissue macrophage populations in homeostasis and following challenge. Our findings are indicative of impact of monocyte ontogeny on in situ differentiation.

immunology↗

bioRxiv2023

p16-dependent upregulation of PD-L1 impairs immunosurveillance of senescent cells

The accumulation of senescent cells promotes aging, but a molecular mechanism that senescent cells use to evade immune clearance and accumulate remains to be elucidated. Here, we report that p16-positive senescent cells upregulate the immune checkpoint protein programmed death-ligand 1 (PD-L1) to accumulate in aging and chronic inflammation. p16-mediated inhibition of CDK4/6 promotes PD-L1 stability in senescent cells via the downregulation of ubiquitin-dependent degradation. p16 expression in infiltrating macrophages induces an immunosuppressive environment that can contribute to an increased burden of senescent cells. Treatment with immunostimulatory anti-PD-L1 antibody enhances the cytotoxic T cell activity and leads to the elimination of p16, PD-L1-positive cells. Our study uncovers a molecular mechanism of p16-dependent regulation of PD-L1 protein stability in senescent cells and reveals the potential of PD-L1 as a target for treating senescence-mediated age-associated diseases.

cell biology↗

bioRxiv2019

Regulation of neutrophil NADPH oxidase by PSTPIP2 affects bone damage in murine autoinflammatory osteomyelitis

Autoinflammatory diseases are characterized by dysregulation of the innate immune system leading to spontaneous inflammation. Pstpip2cmo mouse strain is a well-characterized model of this class of disorders. Due to the mutation leading to the lack of adaptor protein PSTPIP2, these animals suffer from autoinflammatory chronic multifocal osteomyelitis similar to several human syndromes. Current evidence suggests that it is driven by hyperproduction of IL-1{beta} by neutrophil granulocytes. Here we show that in addition to IL-1{beta}, PSTPIP2 also negatively regulates ROS generation by neutrophil NADPH oxidase. Pstpip2cmo neutrophils display highly elevated ROS production in response to a range of stimuli. Inactivation of NADPH oxidase in Pstpip2cmo mice did not affect IL-1{beta} levels and the autoinflammatory process was initiated with similar kinetics. However, the bone destruction was almost completely alleviated, suggesting that dysregulated NADPH oxidase activity is a key factor promoting autoinflammatory bone damage in Pstpip2cmo mice.

immunology↗

bioRxiv2018

Heterocyclic sterol probes for live monitoring of sterol trafficking and lysosomal storage disorders

The monitoring of intracellular cholesterol homeostasis and trafficking is of great importance because their imbalance leads to many pathologies. Reliable tools for cholesterol detection are in demand. This study presents the design and synthesis of fluorescent probes for cholesterol recognition and demonstrates their selectivity by a variety of methods. The construction of dedicated library of 14 probes was based on heterocyclic (pyridine)-sterol derivatives with various attached fluorophores. The most promising probe, a P1-BODIPY conjugate FP-5, was analyzed in detail and showed an intensive labeling of cellular membranes followed by intracellular redistribution into various cholesterol rich organelles and vesicles. FP-5 displayed a stronger signal, with faster kinetics, than the commercial TF-Chol probe. In addition, cells with pharmacologically disrupted cholesterol transport, or with a genetic mutation of cholesterol transporting protein NPC1, exhibited strong and fast FP-5 labeling in the endo/lysosomal compartment, co-localizing with filipin staining of cholesterol. Hence, FP-5 has high potential as a new probe for monitoring cholesterol trafficking and its disorders.\n\nSignificance statementCholesterol is a vital steroid molecule with many important functions in animal cells. Although its dysregulation is associated with an expanding list of clinically important pathologies, the study of its role is limited by a lack of reliable tools for live intracellular monitoring. This study demonstrates the applicability of a novel class of heterocyclic sterol probes. These probes exhibit fast cellular uptake with effective fluorescence labeling of sterol species in a variety of living cells, without a need for artificial carriers. When applied to Niemann-Pick disease type C1 cells, they identified massive accumulation of cholesterol in the endosome/lysosome compartment. Thus, several probes from the same series can also be used for visualizing lysosomal storage disorders and sterol transporting pathologies.

cell biology↗