Biology subjects

Kiselev, A.

Publications and source records attributed to Kiselev, A..

7 recordsLinked to original sources

bioRxiv2026

Dual lineages of Langerhans cells cooperate to restore the immune barrier after skin injury

Langerhans cells (LCs) are key immune sentinels of the epidermis. How this network reorganizes to safeguard epidermal immunity after injury has remained unclear. Here, we uncover a previously unrecognized two-lineage program of LC repopulation during wound repair. Classically, tissue-resident embryonically derived LCs (eLCs) migrate to lymph nodes in response to antigens. In contrast, we find that injury triggers nearby eLCs to migrate into wounds, providing immediate coverage. In parallel, circulating monocytes infiltrate the skin and differentiate into long-lived monocyte-derived LCs (mLCs) that integrate stably into the network. We identify the chemokine receptor CXCR2 as a novel regulator of eLC migration into wounds, distinct from the CXCR4/CCR7 pathways mediating LC egress to lymph nodes. Pharmacological inhibition of CXCR2 impairs directional eLC migration and is accompanied by increased mLC infiltration, preserving immune barrier density. These findings reveal a coordinated and flexible two-lineage repair program that ensures robust restoration of epidermal immunity.

cell biology↗

bioRxiv2025

An intermediate activation state primes Langerhans cell migration from the epidermis

Langerhans cells (LC) are antigen-presenting cells that form dense epidermal networks for immune surveillance. Upon antigen uptake, LCs are activated and subsequently orchestrate immune responses by migrating into the lymphatic system. However, the regulation of transcriptional programs during activation and the behavior of LCs in vivo during this transition remain poorly understood. Therefore, this study combines single-cell transcriptomic analysis with intravital imaging to reconstruct the activation trajectory of epidermal LCs. In particular, the study generates a high-resolution single-cell transcriptomic dataset comprising over 22,000 high-quality epidermal LCs under both homeostatic and injury conditions. Notably, a distinct intermediate activated state that precedes LC migration was identified and characterized at the level of signaling pathways and transcription factors. The integration of this dataset with external datasets from homeostatic and injured skin reveals wound-specific fibroblasts as the major source of C3, which is the central component of the complement cascade. Moreover, intravital imaging of C3-deficient mice and pegcetacoplan treatment demonstrates that C3 contributes to LC accumulation adjacent to wound sites. Collectively, the study findings identify an activated epidermal LC population and implicate complement signaling in the regulation of LC behavior during skin injury.

cell biology↗

bioRxiv2024

Self-organizing human heart assembloids with autologous and developmentally relevant cardiac neural crest-derived tissues

Neural crest cells (NCCs) are a multipotent embryonic cell population of ectodermal origin that extensively migrate during early development and contribute to the formation of multiple tissues. Cardiac NCCs play a critical role in heart development by orchestrating outflow tract septation, valve formation, aortic arch artery patterning, parasympathetic innervation, and maturation of the cardiac conduction system. Abnormal migration, proliferation, or differentiation of cardiac NCCs can lead to severe congenital cardiovascular malformations. However, the complexity and timing of early embryonic heart development pose significant challenges to studying the molecular mechanisms underlying NCC-related cardiac pathologies. Here, we present a sophisticated functional model of human heart assembloids derived from induced pluripotent stem cells, which, for the first time, recapitulates cardiac NCC integration into the human embryonic heart in vitro. NCCs successfully integrated at developmentally relevant stages into heart organoids, and followed developmental trajectories known to occur in the human heart. They demonstrated extensive migration, differentiated into cholinergic neurons capable of generating nerve impulses, and formed mature glial cells. Additionally, they contributed to the mesenchymal populations of the developing outflow tract. Through transcriptomic analysis, we revealed that NCCs acquire molecular features of their cardiac derivatives as heart assembloids develop. NCC-derived parasympathetic neurons formed functional connections with cardiomyocytes, promoting the maturation of the cardiac conduction system. Leveraging this models cellular complexity and functional maturity, we uncovered that early exposure of NCCs to antidepressants harms the development of NCC derivatives in the context of the developing heart. The commonly prescribed antidepressant Paroxetine disrupted the expression of a critical early neuronal transcription factor, resulting in impaired parasympathetic innervation and functional deficits in cardiac tissue. This advanced heart assembloid model holds great promise for high-throughput drug screening and unraveling the molecular mechanisms underlying NCC-related cardiac formation and congenital heart defects. IN BRIEFHuman neural crest heart assembloids resembling the major directions of neural crest differentiation in the human embryonic heart, including parasympathetic innervation and the mesenchymal component of the outflow tract, provide a human-relevant embryonic platform for studying congenital heart defects and drug safety.

bioengineering↗

bioRxiv2024

Human heart assembloids with autologous tissue-resident macrophages recreate physiological immuno-cardiac interactions

Interactions between the developing heart and the embryonic immune system are essential for proper cardiac development and maintaining homeostasis, with disruptions linked to various diseases. While human pluripotent stem cell (hPSC)-derived organoids are valuable models for studying human organ function, they often lack critical tissue-resident immune cells. Here, we introduce an advanced human heart assembloid model, termed hHMA (human heart-macrophage assembloid), which fully integrates autologous cardiac tissue- resident macrophages (MPs) with pre-existing human heart organoids (hHOs). Through multi-omic analyses, we confirmed that these MPs are phenotypically similar to embryonic cardiac tissue-resident MPs and remain viable in the assembloids over time. The inclusion of MPs significantly impacts hHMA development, influencing cardiac cellular composition, boosting cellular communication, remodeling the extracellular matrix, promoting ventricular morphogenesis, and enhancing sarcomeric maturation. Our findings indicate that MPs contribute to homeostasis via efferocytosis, integrate into the cardiomyocyte electrical system, and support catabolic metabolism. To demonstrate the versatility of this model, we developed a platform to study cardiac arrhythmias by chronic exposure to pro-inflammatory factors linked to arrhythmogenesis in clinical settings, successfully replicating key features of inflammasome-mediated atrial fibrillation. Overall, this work introduces a robust platform for examining the role of immune cells in cardiac development, disease mechanisms, and drug discovery, bridging the gap between in vitro models and human physiology. These findings offer insights into cardiogenesis and inflammation-driven heart disease, positioning the hHMA system as an invaluable tool for future cardiovascular research and therapeutic development.

bioengineering↗

bioRxiv2023

Immunometabolic cues recompose and reprogram the microenvironment around biomaterials

Circulating monocytes infiltrate and coordinate immune responses in various inflamed tissues, such as those surrounding implanted biomaterials, affecting therapeutic, diagnostic, tissue engineering and regenerative applications. Here, we show that immunometabolic cues in the biomaterial microenvironment govern CCR2- and CX3CR1-dependent trafficking of immune cells, including neutrophils and monocytes; ultimately, this affects the composition and activation states of macrophage and dendritic cell populations. Furthermore, immunometabolic cues around implants orchestrate the relative composition of proinflammatory, transitory and anti-inflammatory CCR2+, CX3CR1+ and CCR2+CX3CR1+ immune cell populations. Consequently, modifying immunometabolism by glycolytic inhibition drives a pro-regenerative microenvironment in part by myeloid cells around amorphous polylactide implants. In addition to, Arginase 1-expressing myeloid cells, T helper 2 cells and {gamma}{delta}+ T-cells producing IL-4 significantly contribute to shaping the metabolically reprogramed, pro-regenerative microenvironment around crystalline polylactide biomaterials. Taken together, we find that local metabolic states regulate inflammatory processes in the biomaterial microenvironment, with implications for translational medicine.

bioengineering↗

bioRxiv2022

A patterned human heart tube organoid model generated by pluripotent stem cell self-assembly

Human pluripotent stem cells can recapitulate significant features of mammalian organ development in vitro, including key aspects of heart development. We hypothesized that the organoids thus created can be made substantially more relevant by mimicking aspects of in utero gestation, leading to higher physiological and anatomical resemblance to their in vivo counterparts. Here, we report steps towards generating developmentally inspired maturation methodologies to differentiate early human heart organoids into patterned heart-tube-like structures in a reproducible and high-throughput fashion by complete self-organization. The maturation strategy consists of the controlled and stepwise exposure to metabolic (glucose, fatty acids) and hormonal signals (T3, IGF-1) as present during early heart development. These conditions elicit important transcriptomic, cellular, morphological, metabolomic, and functional changes over a 10-day period consistent with continuously increasing heart complexity, maturation, and patterning. Our data reveals the emergence of atrial and ventricular cardiomyocyte populations, valvular cells, epicardial cells, proepicardial-derived cells, endothelial cells, stromal cells, conductance cells, and cardiac progenitors, all of them cell types present in the primitive heart tube. Anatomically, the organoids elongate and develop well-differentiated atrial and ventricular chambers with compacted myocardial muscle walls and a proepicardial organ. For the first time in a completely self-organizing heart organoid, we show anterior-posterior patterning due to an endogenous retinoic acid gradient originating at the atrial pole, where proepicardial and atrial populations reside, mimicking the developmental process present within the primitive heart tube. Collectively, these findings highlight the ability of self-organization and developmental maturation strategies to recapitulate human heart development. Our patterned human heart tube model constitutes a powerful in vitro tool for dissecting the role of different cell types and genes in human heart development, as well as disease modeling congenital heart defects, and represents a step forward in creating fully synthetic human hearts.

bioengineering↗

bioRxiv2020

A DEAD BOX RNA helicase from Medicago truncatula is hijacked by an RNA-binding effector from the root pathogen Aphanomyces euteiches to facilitate host infection

Microbial effectors from plant pathogens are molecules that target host components to facilitate colonization. While eukaryotic pathogens are virtually able to produce hundreds of effectors, the molecular mechanisms allowing effectors to promote infection are still largely unexplored. Here we show that the effector AeSSP1256 from the soilborne oomycete pathogen Aphanomyces euteiches is able to interact with plant RNA. Heterologous expression of AeSSP1256 delays Medicago truncatula host roots development and facilitate pathogen colonization. Transcriptomic analyses of AeSSP1256-expressing roots show a downregulation of genes implicated in ribosome biogenesis pathway. A yeast-two hybrid approach reveals that AeSSP1256 associates with a nucleolar L7 ribosomal protein and a M. truncatula RNA helicase (MtRH10) orthologous to the Arabidopsis RNA helicase RH10. Association of AeSSP1256 with MtRH10 impaired the capacity of MtRH10 to bind nucleic acids. Promoter:GUS composite plants revealed that MtRH10 is expressed preferentially in the meristematic root cells. Missense MtRH10 plants displayed shorter roots with developmental delay and are more susceptible to A. euteiches infection. These results show that the effector AeSSP1256 facilitates pathogen infection by causing stress on plant ribosome biogenesis and by hijacking a host RNA helicase involved in root development and resistance to root pathogens.

plant biology↗