Key Cellular Players Research Articles

Utilising an in silico model to predict outcomes in senescence-driven acute liver injury

Currently liver transplantation is the only treatment option for liver disease, but organ availability cannot meet patient demand. Alternative regenerative therapies, including cell transplantation, aim to modulate the injured microenvironment from inflammation and scarring towards regeneration. The complexity of the liver injury response makes it challenging to identify suitable therapeutic targets when relying on experimental approaches alone. Therefore, we adopted a combined in vivo-in silico approach and developed an ordinary differential equation model of acute liver disease able to predict the host response to injury and potential interventions. The Mdm2fl/fl mouse model of senescence-driven liver injury was used to generate a quantitative dynamic characterisation of the key cellular players (macrophages, endothelial cells, myofibroblasts) and extra cellular matrix involved in liver injury. This was qualitatively captured by the mathematical model. The mathematical model was then used to predict injury outcomes in response to milder and more severe levels of senescence-induced liver injury and validated with experimental in vivo data. In silico experiments using the validated model were then performed to interrogate potential approaches to enhance regeneration. These predicted that increasing the rate of macrophage phenotypic switch or increasing the number of pro-regenerative macrophages in the system will accelerate the rate of senescent cell clearance and resolution. These results showcase the potential benefits of mechanistic mathematical modelling for capturing the dynamics of complex biological systems and identifying therapeutic interventions that may enhance our understanding of injury-repair mechanisms and reduce translational bottlenecks.

Dual nature of type I interferon responses and feedback regulations by SOCS1 dictate malaria mortality

IntroductionType I interferon (IFN-I, IFN-α/β), precisely controlled by multiple regulators, including suppressor of cytokine signaling 1 (SOCS1), is critical for host defense against pathogens. However, the impact of IFN-α/β on malaria parasite infections, beneficial or detrimental, remains controversial. ObjectivesThe contradictory results are suspected to arise from differences in parasite species and host genetic backgrounds. To date, no prior study has employed a comparative approach utilizing two parasite models to investigate the underlying mechanisms of IFN-I response. Moreover, whether and how SOCS1 involves in the distinct IFN-α/β dynamics is still unclear. MethodsHere we perform single-cell RNA sequencing analyses (scRNA-seq) to dissect the dynamics of IFN-α/β responses against P. yoelii 17XL (17XL) and P. berghei ANKA (PbANKA) infections; conduct flow cytometry analysis and functional depletion to identify key cellular players induced by IFN-I; and establish mathematical models to explore the mechanisms underlying the differential IFN-I dynamics regulated by SOCS1. Results17XL stimulates an early protective but insufficient toll-like receptor 7 (TLR7)-interferon regulatory factor 7 (IRF7)-dependent IFN-α/β response, resulting in CD11ahiCD49dhiCD4+ T cell activation to enhance anti-malarial immunity. On the contrary, a late IFN-α/β induction through toll-like receptor 9 (TLR9)-IRF7/ stimulator of interferon genes (STING)- interferon regulatory factor 3 (IRF3) dependent pathways expands programmed cell death protein 1 (PD-1)+CD8+ T cells and impairs host immunity during PbANKA infection. Furthermore, functional assay and mathematical modeling show that SOCS1 significantly suppresses IFN-α/β production via negative feedback and incoherent feed-forward loops (I1-FFL). Additionally, differential activation patterns of various transcriptional factors (TFs) synergistically regulate the distinct IFN-I responses. ConclusionThis study reveals the dual functions of IFN-I in anti-malarial immunity: Early IFN-α/β enhances immune responses against Plasmodium infection by promoting CD11ahiCD49dhiCD4+ T cell, while late IFN-α/β suppresses these response by expanding PD-1+CD8+ T cells. Moreover, both the SOCS1-related network motifs and TFs activation patterns contribute to determine distinct dynamics of IFN-I responses. Hence, our findings suggest therapies targeting SOCS1- or TFs-regulated IFN-I dynamics could be an efficacious approach for preventing malaria and enhancing vaccine efficacy.

Unraveling the Molecular Threads: A Comprehensive Review of the Pathogenesis and Therapeutic Insights Into Allergic Rhinitis.

Allergic rhinitis (AR) is a prevalent inflammatory disorder of the nasal mucosa, triggered by allergen exposure and characterized by symptoms such as sneezing, nasal congestion, itching, and rhinorrhea. This comprehensive review aims to unravel the molecular mechanisms underpinning AR, exploring the pathogenesis from allergen recognition to chronic inflammation and tissue remodelling. Central to the disease are immunoglobulin E (IgE)-mediated hypersensitivity reactions, involving key inflammatory mediators and cellular players such as mast cells, eosinophils, and T cells. Genetic predisposition and environmental factors also play significant roles in susceptibility and disease progression. Therapeutic strategies for AR are varied, ranging from symptomatic relief through antihistamines and nasal corticosteroids to more targeted approaches like allergen-specific immunotherapy. Emerging treatments focus on novel molecular pathways, with a growing emphasis on personalized medicine to optimize patient outcomes. Despite advancements, challenges remain in fully understanding the heterogeneity of AR and developing universally effective treatments. This review synthesizes current knowledge, highlighting critical insights into the molecular basis of AR and their implications for clinical practice. It underscores the need for integrated, multidisciplinary approaches to enhance therapeutic efficacy and calls for ongoing research to address unresolved questions and explore new frontiers in AR management. Through this comprehensive synthesis, the review aims to inform and inspire future research and clinical strategies, ultimately improving the quality of life for individuals affected by AR.

Ursodeoxycholic and chenodeoxycholic bile acids attenuate systemic and liver inflammation induced by lipopolysaccharide in rats.

Bacterial lipopolysaccharide (LPS) induces general inflammation, by activating pathways involving cytokine production, blood coagulation, complement system activation, and acute phase protein release. The key cellular players are leukocytes and endothelial cells, that lead to tissue injury and organ failure. The aim of this study was to explore the anti-inflammatory, antioxidant, and cytoprotective properties of two bile acids, ursodeoxycholic acid (UDCA) and chenodeoxycholic acid (CDCA) in LPS-induced endotoxemia in rats. The experiment involved six distinct groups of Wistar rats, each subjected to different pretreatment conditions: control and LPS groups were pretreated with propylene glycol, as a bile acid solvent, while the other groups were pretreated with UDCA or CDCA for 10 days followed by an LPS injection on day 10. The results showed that both UDCA and CDCA reduced the production of pro-inflammatory cytokines: TNF-α, GM-CSF, IL-2, IFNγ, IL-6, and IL-1β and expression of nuclear factor-κB (NF-κB) induced by LPS. In addition, pretreatment with these bile acids showed a positive impact on lipid profiles, a decrease in ICAM levels, an increase in antioxidant activity (SOD, |CAT, GSH), and a decrease in prooxidant markers (H2O2 and O2-). Furthermore, both bile acids alleviated LPS-induced liver injury. While UDCA and CDCA pretreatment attenuated homocysteine levels in LPS-treated rats, only UDCA pretreatment showed reductions in other serum biochemical markers, including creatine kinase, lactate dehydrogenase, and high-sensitivity troponin I. It can be concluded that both, UDCA and CDCA, although exerted slightly different effects, can prevent the inflammatory responses induced by LPS, improve oxidative stress status, and attenuate LPS-induced liver injury.

Abstract 3797: Unveiling the spatial dynamics of the tumor microenvironment: Integrated RNA and protein profiling on the same slide through automated spatial multiomics analysis

Abstract Spatial biology techniques have revolutionized our approach towards the study of the tumor microenvironment (TME) and its complex cellular interplay. On the one hand, multiplex immunofluorescence (mIF) methods have enabled a precise profiling of immune cells and other key cellular players of the TME while uncovering their spatial distribution and interactions. On the other hand, in situ hybridization (ISH) technologies have shown to provide complementary information to protein profiling such as the mapping of cytokine- and chemokine-expressing cells, essential for comprehending signaling networks and immune activation statuses. Here, we made use of a novel multiomics approach that combines these two biological inputs by integrating RNAscope™ and sequential immunofluorescence (seqIF™) protocols to achieve same-slide co-detection of RNA and protein targets. The combined workflow is automated on COMET™, an advanced tissue staining and imaging platform. Through precise control over temperature and reagent distribution, the instrument ensures maximum efficiency and reproducibility of the assays. The integrated multiomics protocol allows for up to three RNAscope™ detection cycles combined with twelve seqIF™ cycles, for a final 12-plex RNA + 24-plex protein panel. We first showed the capacity of COMET™ platform to fully automate the RNAscope™ protocol and demonstrated its sensitivity and specificity with the analysis of positive and negative control genes on HeLa cell pellets, highlighting the flexibility of sample selection. To illustrate the potential multiomics in unravelling the complexity of the TME, we designed a panel of 12-RNA-targeting probes for key biomarkers of tumor-infiltrating lymphocytes and their activation status, including multiple secreted molecules (e.g., cytokines and proteases). This was combined with a 24-antibody panel for the detection of protein biomarkers, selected to enable the single-cell profiling of different players within the TME. We applied this panel to characterize different human FFPE tumor tissues and showed that the co-detection of RNA and protein biomarkers on the same slide allows a better characterization of key cellular components involved in tumor progression and immune response. Our results highlight the potential of spatial multiomics technologies in enhancing the efficiency of investigations of immune cell behavior and generally the understanding of cellular interplay in the TME. Their full automation on a platform like COMET™ will accelerate analysis and increase robustness by minimizing user intervention, and ultimately helping in the development of prognostic and predictive biomarkers, in the refinement of cancer diagnoses, and in the selection of new personalized therapies. Citation Format: Paula Juricic, Arec Manoukian, Alice Comberlato, Pino Bordignon, Alix Failletaz, Anushka Dikshit, Emerald Doolittle, Rose Delvillar, Steve Zhou, Ching-wei Chang, Li-chong Wang, Saska Brajkovic, Maithreyan Srinivasan, Diego Dupouy. Unveiling the spatial dynamics of the tumor microenvironment: Integrated RNA and protein profiling on the same slide through automated spatial multiomics analysis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3797.

Macrophages: Key Cellular Players in HIV Infection and Pathogenesis.

Although cells of the myeloid lineages, including tissue macrophages and conventional dendritic cells, were rapidly recognized, in addition to CD4+ T lymphocytes, as target cells of HIV-1, their specific roles in the pathophysiology of infection were initially largely neglected. However, numerous studies performed over the past decade, both in vitro in cell culture systems and in vivo in monkey and humanized mouse animal models, led to growing evidence that macrophages play important direct and indirect roles as HIV-1 target cells and in pathogenesis. It has been recently proposed that macrophages are likely involved in all stages of HIV-1 pathogenesis, including virus transmission and dissemination, but above all, in viral persistence through the establishment, together with latently infected CD4+ T cells, of virus reservoirs in many host tissues, the major obstacle to virus eradication in people living with HIV. Infected macrophages are indeed found, very often as multinucleated giant cells expressing viral antigens, in almost all lymphoid and non-lymphoid tissues of HIV-1-infected patients, where they can probably persist for long period of time. In addition, macrophages also likely participate, directly as HIV-1 targets or indirectly as key regulators of innate immunity and inflammation, in the chronic inflammation and associated clinical disorders observed in people living with HIV, even in patients receiving effective antiretroviral therapy. The main objective of this review is therefore to summarize the recent findings, and also to revisit older data, regarding the critical functions of tissue macrophages in the pathophysiology of HIV-1 infection, both as major HIV-1-infected target cells likely found in almost all tissues, as well as regulators of innate immunity and inflammation during the different stages of HIV-1 pathogenesis.

Expansion of distinct peripheral blood myeloid cell subpopulations in patients with rheumatoid arthritis-associated interstitial lung disease

ObjectivesInterstitial lung disease (ILD) is associated with significant mortality in rheumatoid arthritis (RA) patients with key cellular players remaining largely unknown. This study aimed to characterize inflammatory and myeloid derived suppressor cell (MDSC) subpopulations in RA-ILD as compared to RA, idiopathic pulmonary fibrosis (IPF) without autoimmunity, and controls. MethodsPeripheral blood was collected from patients with RA, RA-ILD, IPF, and controls (N = 60, 15/cohort). Myeloid cell subpopulations were identified phenotypically by flow cytometry using the following markers:CD45,CD3,CD19,CD56,CD11b,HLA-DR,CD14,CD16, CD15,CD125,CD33. Functionality of subsets were identified with intracellular arginase-1 (Arg-1) and inducible nitric oxide synthase (iNOS) expression. ResultsThere was increased intermediate (CD14++CD16+) and nonclassical (CD14+/-CD16++) and decreased classical (CD14++CD16-) monocytes in RA, RA-ILD, and IPF vs. control. Intermediate monocytes were higher and classical monocytes were lower in RA-ILD vs. RA but not IPF. Monocytic (m)MDSCs were higher in RA-ILD vs. control and RA but not IPF. Granulocytic (g)MDSCs did not significantly differ. In contrast, neutrophils were increased in IPF and RA-ILD patients with elevated expression of Arg-1 sharing similar dimensional clustering pattern. Eosinophils were increased in RA-ILD vs. controls, RA and IPF. Across cohorts, iNOS was decreased in intermediate/nonclassical monocytes but increased in mMDSCs vs. classical monocytes. In RA-ILD, iNOS positive mMDSCs were increased versus classic monocytes. ConclusionsMyeloid cell subpopulations are significantly modulated in RA-ILD patients with expansion of CD16+ monocytes, mMDSCs, and neutrophils, a phenotypic profile more aligned with IPF than other RA patients. Eosinophil expansion was unique to RA-ILD, potentially facilitating disease pathogenesis and providing a future therapeutic target.

Choroidal Mast Cells and Pathophysiology of Age-Related Macular Degeneration.

Age-related macular degeneration (AMD) remains a leading cause of vision loss in elderly patients. Its etiology and progression are, however, deeply intertwined with various cellular and molecular interactions within the retina and choroid. Among the key cellular players least studied are choroidal mast cells, with important roles in immune and allergic responses. Here, we will review what is known regarding the pathophysiology of AMD and expand on the recently proposed intricate roles of choroidal mast cells and their activation in outer retinal degeneration and AMD pathogenesis. We will focus on choroidal mast cell activation, the release of their bioactive mediators, and potential impact on ocular oxidative stress, inflammation, and overall retinal and choroidal health. We propose an important role for thrombospondin-1 (TSP1), a major ocular angioinflammatory factor, in regulation of choroidal mast cell homeostasis and activation in AMD pathogenesis. Drawing from limited studies, this review underscores the need for further comprehensive studies aimed at understanding the precise roles changes in TSP1 levels and choroidal mast cell activity play in pathophysiology of AMD. We will also propose potential therapeutic strategies targeting these regulatory pathways, and highlighting the promise they hold for curbing AMD progression through modulation of mast cell activity. In conclusion, the evolving understanding of the role of choroidal mast cells in AMD pathogenesis will not only offer deeper insights into the underlying mechanisms but will also offer opportunities for development of novel preventive strategies.

Complex Spatio-Temporal Interplay of Distinct Immune and Bone Cell Subsets during Bone Fracture Healing.

The healing of a bone injury is a highly complex process involving a multitude of different tissue and cell types, including immune cells, which play a major role in the initiation and progression of bone regeneration. We histologically analyzed the spatio-temporal occurrence of cells of the innate immune system (macrophages), the adaptive immune system (B and T lymphocytes), and bone cells (osteoblasts and osteoclasts) in the fracture area of a femoral osteotomy over the healing time. This study was performed in a bone osteotomy gap mouse model. We also investigated two key challenges of successful bone regeneration: hypoxia and revascularization. Macrophages were present in and around the fracture gap throughout the entire healing period. The switch from initially pro-inflammatory M1 macrophages to the anti-inflammatory M2 phenotype coincided with the revascularization as well as the appearance of osteoblasts in the fracture area. This indicates that M2 macrophages are necessary for the restoration of vessels and that they also play an orchestrating role in osteoblastogenesis during bone healing. The presence of adaptive immune cells throughout the healing process emphasizes their essential role for regenerative processes that exceeds a mere pathogen defense. B and T cells co-localize consistently with bone cells throughout the healing process, consolidating their crucial role in guiding bone formation. These histological data provide, for the first time, comprehensive information about the complex interrelationships of the cellular network during the entire bone healing process in one standardized set up. With this, an overall picture of the spatio-temporal interplay of cellular key players in a bone healing scenario has been created. A spatio-temporal distribution of immune cells, bone cells, and factors driving bone healing at time points that are decisive for this process-especially during the initial steps of inflammation and revascularization, as well as the soft and hard callus phases-has been visualized. The results show that the bone healing cascade does not consist of five distinct, consecutive phases but is a rather complex interrelated and continuous process of events, especially at the onset of healing.

Bronchial Asthma, Airway Remodeling and Lung Fibrosis as Successive Steps of One Process.

Bronchial asthma is a heterogeneous disease characterized by persistent respiratory system inflammation, airway hyperreactivity, and airflow obstruction. Airway remodeling, defined as changes in airway wall structure such as extensive epithelial damage, airway smooth muscle hypertrophy, collagen deposition, and subepithelial fibrosis, is a key feature of asthma. Lung fibrosis is a common occurrence in the pathogenesis of fatal and long-term asthma, and it is associated with disease severity and resistance to therapy. It can thus be regarded as an irreversible consequence of asthma-induced airway inflammation and remodeling. Asthma heterogeneity presents several diagnostic challenges, particularly in distinguishing between chronic asthma and other pulmonary diseases characterized by disruption of normal lung architecture and functions, such as chronic obstructive pulmonary disease. The search for instruments that can predict the development of irreversible structural changes in the lungs, such as chronic components of airway remodeling and fibrosis, is particularly difficult. To overcome these challenges, significant efforts are being directed toward the discovery and investigation of molecular characteristics and biomarkers capable of distinguishing between different types of asthma as well as between asthma and other pulmonary disorders with similar structural characteristics. The main features of bronchial asthma etiology, pathogenesis, and morphological characteristics as well as asthma-associated airway remodeling and lung fibrosis as successive stages of one process will be discussed in this review. The most common murine models and biomarkers of asthma progression and post-asthmatic fibrosis will also be covered. The molecular mechanisms and key cellular players of the asthmatic process described and systematized in this review are intended to help in the search for new molecular markers and promising therapeutic targets for asthma prediction and therapy.

Molecular mechanisms of long bone growth and chondrocyte regulation: A narrative review

Long bone growth is a fundamental determinant of final height. Growth, metabolism, and differentiation of chondrocytes, which are the key cellular players in this process, are regulated by systemic hormones, local factors, and cellular signaling pathways. This review provides an overview of the structural aspects of the growth plate, factors influencing chondrocyte function, and their impact on longitudinal bone growth. Systemic factors, including growth hormone, sex hormones, thyroid hormone, glucocorticoids, leptin, and insulin significantly affect chondrocyte proliferation and hypertrophy. Local factors, including transcription factors such as SRY-box 9 protein (SOX9), Runt-related transcription factor 2 (RUNX2), and bone morphogenetic proteins (BMPs), along with signaling pathways such as the Wnt pathway, play critical roles in chondrocyte proliferation and differentiation. These factors regulate gene expression, cell differentiation, and extracellular matrix synthesis. Additionally, Indian hedgehog (Ihh) and C-type natriuretic peptide (CNP) are involved in the complex signaling network governing chondrocyte function. Understanding molecular mechanisms underlying normal growth plate function has provided valuable insights into the genetic defects that impact growth and foundation for the development of effective therapeutic strategies for individuals with growth disorders.

Deciphering pathogenic cellular module at single-cell resolution in checkpoint inhibitor-related pneumonitis

Checkpoint inhibitor pneumonitis (CIP) is the most common fatal immune-related adverse event; however, its pathophysiology remains largely unknown. Comprehensively dissecting the key cellular players and molecular pathways associated with CIP pathobiology is critical for precision diagnosis and develop novel therapy strategy of CIP. Herein, we performed a comprehensive single-cell transcriptome analysis to dissect the complexity of the immunological response in the bronchoalveolar lavage fluid (BALF) microenvironment. CIP was characterized by a dramatic accumulation of CXCL13+ T cells and hyperinflammatory CXCL9+ monocytes. T-cell receptor (TCR) analysis revealed that CXCL13+ T cells exhibited hyperexpanded- TCR clonotypes, and pseudotime analysis revealed a potential differentiation trajectory from naïve to cytotoxic effector status. Monocyte trajectories showed that LAMP3+ DCs derived from CXCL9+ monocytes possessed the potential to migrate from tumors to the BALF, whereas the differentiation trajectory to anti-inflammatory macrophages was blocked. Intercellular crosstalk analysis revealed the signaling pathways such as CXCL9/10/11-CXCR3, FASLG-FAS, and IFNGR1/2-IFNG were activated in CIP+ samples. We also proposed a novel immune signature with high diagnostic power to distinguish CIP+ from CIP− samples (AUC = 0.755). Our data highlighted key cellular players, signatures, and interactions involved in CIP pathogenesis.

Small Tweaks, Major Changes: Post-Translational Modifications That Occur within M2 Macrophages in the Tumor Microenvironment.

The majority of proteins are subjected to post-translational modifications (PTMs), regardless of whether they occur in or after biosynthesis of the protein. Capable of altering the physical and chemical properties and functions of proteins, PTMs are thus crucial. By fostering the proliferation, migration, and invasion of cancer cells with which they communicate in the tumor microenvironment (TME), M2 macrophages have emerged as key cellular players in the TME. Furthermore, growing evidence illustrates that PTMs can occur in M2 macrophages as well, possibly participating in molding the multifaceted characteristics and physiological behaviors in the TME. Hence, there is a need to review the PTMs that have been reported to occur within M2 macrophages. Although there are several reviews available regarding the roles of M2 macrophages, the majority of these reviews overlooked PTMs occurring within M2 macrophages. Considering this, in this review, we provide a review focusing on the advancement of PTMs that have been reported to take place within M2 macrophages, mainly in the TME, to better understand the performance of M2 macrophages in the tumor microenvironment. Incidentally, we also briefly cover the advances in developing inhibitors that target PTMs and the application of artificial intelligence (AI) in the prediction and analysis of PTMs at the end of the review.

Understanding fibrosis pathogenesis via modeling macrophage-fibroblast interplay in immune-metabolic context

Fibrosis is a progressive biological condition, leading to organ dysfunction in various clinical settings. Although fibroblasts and macrophages are known as key cellular players for fibrosis development, a comprehensive functional model that considers their interaction in the metabolic/immunologic context of fibrotic tissue has not been set up. Here we show, by transcriptome-based mathematical modeling in an in vitro system that represents macrophage-fibroblast interplay and reflects the functional effects of inflammation, hypoxia and the adaptive immune context, that irreversible fibrosis development is associated with specific combinations of metabolic and inflammatory cues. The in vitro signatures are in good alignment with transcriptomic profiles generated on laser captured glomeruli and cortical tubule-interstitial area, isolated from human transplanted kidneys with advanced stages of glomerulosclerosis and interstitial fibrosis/tubular atrophy, two clinically relevant conditions associated with organ failure in renal allografts. The model we describe here is validated on tissue based quantitative immune-phenotyping of biopsies from transplanted kidneys, demonstrating its feasibility. We conclude that the combination of in vitro and in silico modeling represents a powerful systems medicine approach to dissect fibrosis pathogenesis, applicable to specific pathological conditions, and develop coordinated targeted approaches.

Advances in Pigmentation Management: A Multipronged Approach.

Key cellular players regulating human skin pigmentation include melanocytes in the epidermis that synthesize melanin, neighboring keratinocytes that receive and distribute melanin in the upper layers, and fibroblasts in the dermis that affect overlying melanocytes and keratinocytes. In addition, endocrine factors from the blood supply (endothelial cells) and inflammation-related factors play a role. Thus, new strategies for affecting pigmentation need to consider these multiple cell lines to adequately cover various causes and disease processes associated with hyperpigmentation. Pathophysiologic mechanisms and cellular pathways involved in melanogenesis were thoroughly reviewed with particular emphasis on the cellular interplay involved in the process. A complex system of interlinking and independent pathways was defined and described demonstrating differing pathways for altered pigmentary disorders - melasma associated with endothelial cell interactions; post inflammatory hyperpigmentation associated with keratinocyte inflammatory mediators (PGE2 in particular); and photodamage involving all 4 cell types. In vitro validation studies were then undertaken to define differing cell group gene expression profiles with selected peptides and other active agents. Melanocytic production of pigment was then tested with these agents to identify key potential players capable of limiting pigmentation. Hexapeptide-12 and lactoferrin (melanocytes), Hexapeptide-11 (in keratinocytes), and phosphatidylserine (endothelial cells) were identified as major inhibitors of melanogenesis based on their gene expression profiles. This was confirmed by secondary melanin production tests performed on melanocytic lines. Additional active agents were also identified as inhibitors of melanocytic production of melanin, and together, these constituents formed the basis for a novel formulation for use in pigmentary disorders. A comprehensive scientific narrative of the various facets relating to pigmentation has been presented including differing pathways affecting varied cell lines that effect pigment production. Based on this concept, actives were tested using gene expression studies as well as in vitro melanogenic model testing in different cell lines. Using this novel multi-faceted approach, we have selected and validated a series of active agents to be used in a formulation targeting the complex problem of hyperpigmentation. J Drugs Dermatol. 2022;21(11):1206-1220. doi:10.36849/JDD.7013.

Current Concepts of Vitiligo Immunopathogenesis.

Vitiligo is an acquired immune-mediated disorder of pigmentation clinically characterized by well-defined depigmented or chalk-white macules and patches on the skin. The prevalence of vitiligo varies by geographical area, affecting 0.5% to 2% of the population. The disease imposes a significant psychological burden due to its major impact on patients’ social and emotional aspects of life. Given its autoimmune background, vitiligo is frequently associated with other autoimmune diseases or immune-mediated diseases. Vitiligo is a multifaceted disorder that involves both genetic predisposition and environmental triggers. In recent years, major predisposing genetic loci for the development of vitiligo have been discovered. The current findings emphasize the critical role of immune cells and their mediators in the immunopathogenesis of vitiligo. Oxidative-stress-mediated activation of innate immunity cells such as dendritic cells, natural killer, and ILC-1 cells is thought to be a key event in the early onset of vitiligo. Innate immunity cells serve as a bridge to adaptive immunity cells including T helper 1 cells, cytotoxic T cells and resident memory T cells. IFN-γ is the primary cytokine mediator that activates the JAK/STAT pathway, causing keratinocytes to produce the key chemokines CXCL9 and CXCL10. Complex interactions between immune and non-immune cells finally result in apoptosis of melanocytes. This paper summarizes current knowledge on the etiological and genetic factors that contribute to vitiligo, with a focus on immunopathogenesis and the key cellular and cytokine players in the disease’s inflammatory pathways.

Inflammation-induced arterial dysfunction in atherosclerosis; the modulating action of mesenchymal stem cell-derived extracellular vesicles

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – EU funding. Main funding source(s): CNCS-UEFISCDI Background Atherosclerosis is a progressive, chronic inflammatory disease of the large arteries caused by the constant accumulation of cholesterol, followed by endothelial dysfunction and vascular inflammation. We hypothesised that delivery of extracellular vesicles (EVs), recognized for their potential as therapeutic targets and tools, could restore vascular function in atherosclerosis. Purpose The goal was to evaluate vascular consequences of inflammation along with its key molecular and cellular players as intermediate endpoints for cardiovascular disease (CVD), and to explore ‘in vivo’ the potential beneficial effect of EVs from subcutaneous adipose tissue (EVs-ADSCs) or bone marrow mesenchymal stem cells (EVs-MSCs). Methods Our experimental animal model of atherosclerosis (hypertensive-hyperlipidemic hamster-HH) was treated with EVs-ADSCs or EVs-MSCs transfected or not with Smad2/3siRNA. For comparison, healthy animals (control group) or HH group transfected with Smad2/3siRNA alone were used. Results The results showed that compared with the control group, HH group displayed: (1) a marked increase of plasmatic parameter levels (cholesterol, LDL-cholesterol, triglycerides); (2) an amplification of expression of inflammatory markers with role in vascular dysfunction (COL1A, α-SMA, Cx43, VCAM-1, MMP-2); (3) a massive infiltration of total/M1 macrophages and T-cells into thoracic aorta and carotid artery; (4) an increased level of cytosolic ROS production; (5) a significant increase in plasma concentration of TGF-β1 and Ang II proteins; (6) significant structural (thickening of the arterial wall and reduction of the inner diameter) and functional changes (reduced distensibility, increased pulse wave velocity and velocity time integral, and diminished contractile responses to noradrenaline (NA) and reduced relaxation to acetylcholine (ACh)) in both thoracic aorta and carotid artery; (7) an altered protein expression profile (Smad2/3, ATF-2, NF-kBp50/p65) and a significant increase in the expression level of the miRNA panel (miR21, miR-29a, miR-192, miR-200b, miR-210, miR-146a) associated with inflammation-induced endothelial dysfunction. In addition, by comparison with the HH group, all treatment groups showed a significant decrease in the levels of plasma parameters, but also a noticeable improvement in the structure and function of the investigated blood vessels along with a decrease in the key molecules that modulate the inflammatory response through soluble mediators and cellular components. Conclusion We can conclude that the administration for 4 months of atherogenic diet activated key regulatory molecules in the atherosclerotic process, respectively TGF-β1, Ang II and ROS, modulating main orchestrators of inflammation-mediated atherosclerotic CVD progression. Also, EV-based treatment of inflammation, especially the EV-ADSC-based one, led to regression of arterial dysfunction and its key molecular players.

Selective cellular probes for mammalian thioredoxin reductase TrxR1: Rational design of RX1, a modular 1,2-thiaselenane redox probe

Quantifying the activity of key cellular redox players is crucial for understanding physiological homeostasis, and for targeting their perturbed states in pathologies including cancer and inflammatory diseases. However, cellularly-selective probes for oxidoreductase turnover are sorely lacking. We rationally developed the first probes that selectively target the mammalian selenoprotein thioredoxin reductase (TrxR), using a cyclic selenenylsulfide oriented to harness TrxR's unique selenolthiol chemistry while resisting the cellular monothiol background. Lead probe RX1 had excellent TrxR1-selective performance in cells, cross-validated by knockout, selenium starvation, knock-in, and chemical inhibitors. Its background-free fluorogenicity enabled us to perform the first quantitative high-throughput live cell screen for TrxR1 inhibitors, which indicated that tempered SNAr electrophiles may be more selective TrxR drugs than the classical electrophiles used hitherto. The RX1 design thus sets the stage for in vivo imaging of the activity of this key oxidoreductase in health and disease, and can also drive TrxR1-inhibitor drug design.

Preterm Birth in Women With HIV: The Role of the Placenta.

Maternal HIV infection is associated with an increased risk of preterm birth (PTB). However, the mechanisms underlying this increased risk in women with HIV remain poorly understood. In this regard, it is well-established that labor is an inflammatory process and premature activation of the pro-inflammatory signals (associated with labor) can result in preterm labor which can subsequently lead to PTB. HIV infection is known to cause severe immune dysregulation within its host characterized by altered immune profiles, chronic inflammation and eventually, the progressive failure of the immune system. The human placenta comprises different immune cell subsets, some of which play an important role during pregnancy including participating in the inflammatory processes that accompany labor. It is therefore plausible that HIV/antiretroviral therapy (ART)-associated immune dysregulation within the placental microenvironment may underlie the increased risk of PTB reported in women with HIV. Here, we review evidence from studies that point toward the placental origin of spontaneous PTB and discuss possible ways maternal HIV infection and/or ART could increase this risk. We focus on key cellular players in the maternal decidua including natural killer cells, CD4+ T cells including CD4+ regulatory T cells, CD8+ T cells as well as macrophages.

Pathogenesis, Diagnosis and Management of Obstetric Antiphospholipid Syndrome: A Comprehensive Review.

Antiphospholipid syndrome is an autoimmune disorder characterized by vascular thrombosis and/or pregnancy morbidity associated with persistent antiphospholipid antibody positivity. Cases fulfilling the Sydney criteria for obstetric morbidity with no previous thrombosis are known as obstetric antiphospholipid syndrome (OAPS). OAPS is the most identified cause of recurrent pregnancy loss and late-pregnancy morbidity related to placental injury. Cases with incomplete clinical or laboratory data are classified as obstetric morbidity APS (OMAPS) and non-criteria OAPS (NC-OAPS), respectively. Inflammatory and thrombotic mechanisms are involved in the pathophysiology of OAPS. Trophoblasts, endothelium, platelets and innate immune cells are key cellular players. Complement activation plays a crucial pathogenic role. Secondary placental thrombosis appears by clot formation in response to tissue factor activation. New risk assessment tools could improve the prediction of obstetric complication recurrences or thromboses. The standard-of-care treatment consists of low-dose aspirin and prophylactic low molecular weight heparin. In refractory cases, the addition of hydroxychloroquine, low-dose prednisone or IVIG improve pregnancy outcomes. Statins and eculizumab are currently being tested for treating selected OAPS women. Finally, we revisited recent insights and concerns about the pathophysiology, diagnosis and management of OAPS.