Influence of gene modification in biological behaviors and responses of mouse lung telocytes to inflammation

Exosomes enriched by miR-429-3p derived from ITGB1 modified Telocytes alleviates hypoxia-induced pulmonary arterial hypertension through regulating Rac1 expression

BACKGROUND

Recent studies have emphasized the critical role of Telocytes (TCs)-derived exosomes in organ tissue injury and repair. Our previous research showed a significant increase in ITGB1 within TCs. Pulmonary Arterial Hypertension (PAH) is marked by a loss of microvessel regeneration and progressive vascular remodeling. This study aims to investigate whether exosomes derived from ITGB1-modified TCs (ITGB1-Exo) could mitigate PAH.

METHODS

We analyzed differentially expressed microRNAs (DEmiRs) in TCs using Affymetrix Genechip miRNA 4.0 arrays. Exosomes isolated from TC culture supernatants were verified through transmission electron microscopy and Nanoparticle Tracking Analysis. The impact of miR-429-3p-enriched exosomes (Exo-ITGB1) on hypoxia-induced pulmonary arterial smooth muscle cells (PASMCs) was evaluated using CCK-8, transwell assay, and inflammatory factor analysis. A four-week hypoxia-induced mouse model of PAH was constructed, and H&E staining, along with Immunofluorescence staining, were employed to assess PAH progression.

RESULTS

Forty-five miRNAs exhibited significant differential expression in TCs following ITGB1 knockdown. Mus-miR-429-3p, significantly upregulated in ITGB1-overexpressing TCs and in ITGB1-modified TC-derived exosomes, was selected for further investigation. Exo-ITGB1 notably inhibited the migration, proliferation, and inflammation of PASMCs by targeting Rac1. Overexpressing Rac1 partly counteracted Exo-ITGB1's effects. In vivo administration of Exo-ITGB1 effectively reduced pulmonary vascular remodeling and inflammation.

CONCLUSIONS

Our findings reveal that ITGB1-modified TC-derived exosomes exert anti-inflammatory effects and reverse vascular remodeling through the miR-429-3p/Rac1 axis. This provides potential therapeutic strategies for PAH treatment.

Telocytes: current methods of research, challenges and future perspectives

Telocytes (TCs) are CD34-positive interstitial cells that have long cytoplasmic projections, called telopodes; they have been identified in several organs and in various species. These cells establish a complex communication network between different stromal and epithelial cell types, and there is growing evidence that they play a key role in physiology and pathology. In many tissues, TC network impairment has been implicated in the onset and progression of pathological conditions, which makes the study of TCs of great interest for the development of novel therapies. In this review, we summarise the main methods involved in the characterisation of these cells as well as their inherent difficulties and then discuss the functional assays that are used to uncover the role of TCs in normal and pathological conditions, from the most traditional to the most recent. Furthermore, we provide future perspectives in the study of TCs, especially regarding the establishment of more precise markers, commercial lineages and means for drug delivery and genetic editing that directly target TCs.

Integrin beta1 mediates the effect of telocytes on mesenchymal stem cell proliferation and migration in the treatment of acute lung injury

Co-transplantation of mesenchymal stem cells (MSCs) with telocytes (TCs) was found to have therapeutic effects, although the mechanism of intercellular communication is still unknown. Our current studies aim at exploring the potential molecular mechanisms of TCs interaction and communication with MSCs with a focus on integrin beta1 (ITGB1) in TCs. We found that the co-culture of MSCs with ITGB1-deleted TCs (TCITGB1-ko ) changed the proliferation, differentiation and growth dynamics ability of MSC in responses to LPS or PI3K inhibitor. Changes of MSC proliferation and apoptosis were accompanied with the dysregulation of cytokine mRNA expression in MSCs co-cultured with TCITGB1-ko during the exposure of PI3Kα/δ/β inhibitor, of which IL-1β, IL-6 and TNF-α increased, while IFN-γ, IL-4 and IL-10 decreased. The responses of PI3K p85, PI3K p110 and pAKT of MSCs co-cultured with TCITGB1-ko to LPS or PI3K inhibitor were opposite to those with ITGB1-presented TCs. The intraperitoneal injection of TCITGB1-ko , TCvector or MSCs alone, as well as the combination of MSCs with TCITGB1-ko or TCvector exhibited therapeutic effects on LPS-induced acute lung injury. Thus, our data indicate that telocyte ITGB1 contributes to the interaction and intercellular communication between MSCs and TCs, responsible for influencing other cell phenomes and functions.

Telocytes and inflammation: A review

Telocytes are a new type of interstitial cell with a diverse morphology and important functions, such as mechanical support, signal transduction, immune regulation, and tissue repair. In this paper, the origin and physiological and pathological functions of telocytes as well as their role in inflammation will be discussed, and the functions and targets of telocytes in inflammation will be fully reviewed, which may contribute to a new therapeutic strategy for inflammatory diseases in the future.

Telocytes reduce oxidative stress by downregulating DUOX2 expression in inflamed lungs of mice

Telocytes (TCs), a novel type of interstitial cells, have been found to participate in tissue protection and repair. In this study, we investigated the antioxidative effects of TCs in inflamed lungs of mice. Acute respiratory distress syndrome (ARDS) mice were used as models of inflamed lungs of mice. Gene sequencing was used to screen the differentially expressed miRNAs in TCs after lipopolysaccharide (LPS) stimulation. AntagomiR-146a-5p-pretreated TCs were first injected into mice, and antioxidant activity of TCs was estimated. TCs, RAW264.7 cells, and MLE-12 cells were collected for the detection of expressions of NOX1-4, DUOX1-2, SOD1-3, GPX1-2, CAT, Nrf2, miR-146a-5p, and miR-21a-3p after LPS stimulation. Silencing miRNAs were delivered to examine the involved signaling pathways. Oxidative stress was examined by measuring malondialdehyde (MDA) levels. We found that microRNA-146a-5p and microRNA-21a-3p were upregulated in TCs after LPS stimulation. ARDS mice that were preinfused with TCs had lower lung tissue injury scores, lung wet-dry ratios, white blood cell counts in alveolar lavage fluid and lower MDA concentrations in lung tissue. However, in antagomiR-146a-5p-pretreated ARDS mice, the infusion of TCs caused no corresponding changes. After LPS stimulation, DUOX2 and MDA concentrations were downregulated in TCs, while DUOX2 was restored by antagomiR-146a-5p in TCs. Dual-luciferase reporter assay confirmed that CREB1 was downregulated by miR-146a-5p, while DUOX2 was downregulated by CREB1, which was confirmed by treating TCs with a specific CREB1 inhibitor. This study demonstrates that LPS stimulation upregulates miR-146a-5p in TCs, which downregulates the CREB1/DUOX2 pathway, resulting in a decrease in oxidative stress in cultured TCs. TCs reduce LPS-induced oxidative stress by decreasing DUOX2 in inflamed lungs of mice.

Roles of pulmonary telocytes in airway epithelia to benefit experimental acute lung injury through production of telocyte-driven mediators and exosomes

Background

Telocytes (TCs) are experimentally evidenced as an alternative of cell therapies for organ tissue injury and repair. The aims of the present studies are to explore direct roles of TCs and the roles of TC-derived exosomes in support of experimental acute lung injury (ALI) in vivo or in vitro.

Materials and methods

The roles of TCs in experimental ALI were firstly estimated. Phosphoinositide 3-kinase (PI3K) p110δ and α/δ/β isoform inhibitors were used in study dynamic alterations of bio-behaviors, and in expression of functional factors of TCs per se and TC-co-cultured airway epithelial cells during the activation with lipopolysaccharide (LPS). TC-driven exosomes were furthermore characterized for intercellular communication by which activated or non-activated TCs interacted with epithelia.

Results

Our results showed that TCs mainly prevented from lung tissue edema and hemorrhage and decreased the levels of VEGF-A and MMP9 induced by LPS. Treatment with CAL101 (PI3K p110δ inhibitor) and LY294002 (PI3Kα/δ/β inhibitor) could inhibit TC movement and differentiation and increase the number of dead TCs. The expression of Mtor, Hif1α, Vegf-a, or Mmp9 mRNA increased in TCs challenged with LPS, while Mtor, Hif1α, and Vegf-a even more increased after adding CAL101 or Mtor after adding LY. The rate of epithelial cell proliferation was higher in co-culture of human bronchial epithelial (HBE) and TCs than that in HBE alone under conditions with or without LPS challenge or when cells were treated with LPS and CAL101 or LY294002. The levels of mTOR, HIF1α, or VEGF-A significantly increased in mono-cultured or co-cultured cells, challenged with LPS as compared with those with vehicle. LPS-pretreated TC-derived exosomes upregulated the expression of AKT, p-AKT, HIF1α, and VEGF-A protein of HBE.

Conclusion

The present study demonstrated that intraperitoneal administration of TCs ameliorated the severity of lung tissue edema accompanied by elevated expression of VEGF-A. TCs could nourish airway epithelial cells through nutrients produced from TCs, increasing epithelial cell proliferation, and differentiation as well as cell sensitivity to LPS challenge and PI3K p110δ and α/δ/β inhibitors, partially through exosomes released from TCs.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s10565-021-09670-5.

A cellular census of human peripheral immune cells identifies novel cell states in lung diseases

Increasing evidence supports a central role of the immune system in lung diseases. Understanding how immunological alterations between lung diseases provide opportunities for immunotherapy. Exhausted T cells play a key role of immune suppression in lung cancer and chronic obstructive pulmonary disease was proved in our previous study. The present study aims to furthermore define molecular landscapes and heterogeneity of systemic immune cell target proteomic and transcriptomic profiles and interactions between circulating immune cells and lung residential cells in various lung diseases. We firstly measured target proteomic profiles of circulating immune cells from healthy volunteers and patients with stable pneumonia, stable asthma, acute asthma, acute exacerbation of chronic obstructive pulmonary disease, chronic obstructive pulmonary disease and lung cancer, using single-cell analysis by cytometry by time-of-flight with 42 antibodies. The nine immune cells landscape was mapped among those respiratory system diseases, including CD4+ T cells, CD8+ T cells, dendritic cells, B cells, eosinophil, γδT cells, monocytes, neutrophil and natural killer cells. The double-negative T cells and exhausted CD4+ central memory T cells subset were identified in patients with acute pneumonia. This T subset expressed higher levels of T-cell immunoglobulin and mucin domain-containing protein 3 (Tim3) and T-cell immunoreceptor with Ig and ITIM domains (TIGIT) in patients with acute pneumonia and stable pneumonia. Biological processes and pathways of immune cells including immune response activation, regulation of cell cycle and pathways in cancer in peripheral blood immune cells were defined by bulk RNA sequencing (RNA-seq). The heterogeneity among immune cells including CD4+ , CD8+ T cells and NK T cells by single immune cell RNA-seq with significant difference was found by single-cell sequencing. The effect of interstitial telocytes on the immune cell types and immune function was finally studied and the expressions of CD8a and chemokine C-C motif receptor 7 (CCR7) were increased significantly in co-cultured groups. Our data indicate that proteomic and transcriptomic profiles and heterogeneity of circulating immune cells provides new insights for understanding new molecular mechanisms of immune cell function, interaction and modulation as a source to identify and develop biomarkers and targets for lung diseases.

Identification of the Molecular Basis of Nanocurcumin-Induced Telocyte Preservation within the Colon of Ulcerative Colitis Rat Model

Background

Telocytes (TCs) are a distinct type of interstitial cells that play a vital role in the pathogenesis of ulcerative colitis and colonic tissue hemostasis. The aim of this study was to examine the effect of nanocurcumin (NC) on the morphometric and immunohistochemical characterization of TCs in the ulcerative colitis (UC) rat model.

Methods

Forty rats were randomly divided into control, NC, UC, and UC+NC groups. At the end of the experiment, the colon was dissected and prepared for histopathological and immunohistochemical assessment. Tissue homogenates were prepared for real-time PCR assessment of interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), and transforming growth factor-beta (TGF-β) gene expression. Our results revealed extensive mucosal damage with inflammatory cell infiltration, significant reduction of CD34, and vimentin immunostained TCs in the colon of the UC group with significant elevation of expression of IL-6, TNF-α, and TGF-β. The UC+NC-treated group revealed significant elevation of TC count compared to the UC group besides, a significant reduction of the three gene expression.

Conclusion

NC successfully targeted the colonic tissue, improved the mucosal lesion, preserve TCs distribution, and count through its anti-inflammatory and fibrinolytic properties.

Mechanisms of interactions between lung-origin telocytes and mesenchymal stem cells to treat experimental acute lung injury

Acute lung injury is a serious form and major cause of patient death and still needs efficient therapies. The present study evidenced that co-transplantation of mesenchymal stem cells (MSCs) and telocytes (TCs) improved the severity of experimental lung tissue inflammation, edema, and injury, where TCs increased MSCs migration into the lung and the capacity of MSCs proliferation and movement. Of molecular mechanisms, Osteopontin-dominant networks were active in MSCs and TCs, and might play supportive and nutrimental roles in the interaction between MSCs and TCs, especially activated TCs by lipopolysaccharide. The interaction between epidermal growth factor and its receptor from MSCs and TCs could play critical roles in communications between MSCs and TCs, responsible for MSCs proliferation and movement, especially after inflammatory activation. Our studies provide the evidence that TCs possess nutrimental and supportive roles in implanted MSCs, and co-transplantation of MSCs and TCs can be a new alternative in the therapy of acute lung injury.

A Two-Step Immunomagnetic Microbead-Based Method for the Isolation of Human Primary Skin Telocytes/CD34+ Stromal Cells

Telocytes (TCs), commonly referred to as TCs/CD34+ stromal cells, are a peculiar type of interstitial cells with distinctive morphologic traits that are supposed to exert several biological functions, including tissue homeostasis regulation, cell-to-cell signaling, immune surveillance, and reparative/regenerative effects. At present, the majority of studies investigating these cells are mainly descriptive and focus only on their morphology, with a consequent paucity of functional data. To gain relevant insight into the possible functions of TCs, in vitro analyses are clearly required, but currently, the protocols for TC isolation are only at the early stages and not fully standardized. In the present in vitro study, we describe a novel methodology for the purification of human primary skin TCs through a two-step immunomagnetic microbead-based cell separation (i.e., negative selection for CD31 followed by positive selection for CD34) capable of discriminating these cells from other connective tissue-resident cells on the basis of their different immunophenotypic features. Our experiments clearly demonstrated that the proposed method allows a selective purification of cells exhibiting the peculiar TC morphology. Isolated TCs displayed very long cytoplasmic extensions with a moniliform silhouette (telopodes) and presented an immunophenotypic profile (CD31−/CD34+/PDGFRα+/vimentin+) that unequivocally differentiates them from endothelial cells (CD31+/CD34+/PDGFRα−/vimentin+) and fibroblasts (CD31−/CD34−/PDGFRα+/vimentin+). This novel methodology for the isolation of TCs lays the groundwork for further research aimed at elucidating their functional properties and possible translational applications, especially in the field of regenerative medicine.

Inferring Gene Networks in Bone Marrow Hematopoietic Stem Cell-Supporting Stromal Niche Populations

The cardinal property of bone marrow (BM) stromal cells is their capacity to contribute to hematopoietic stem cell (HSC) niches by providing mediators assisting HSC functions. In this study we first contrasted transcriptomes of stromal cells at different developmental stages and then included large number of HSC-supportive and non-supportive samples. Application of a combination of algorithms, comprising one identifying reliable paths and potential causative relationships in complex systems, revealed gene networks characteristic of the BM stromal HSC-supportive capacity and of defined niche populations of perivascular cells, osteoblasts, and mesenchymal stromal cells. Inclusion of single-cell transcriptomes enabled establishing for the perivascular cell subset a partially oriented graph of direct gene-to-gene interactions. As proof of concept we showed that R-spondin-2, expressed by the perivascular subset, synergized with Kit ligand to amplify ex vivo hematopoietic precursors. This study by identifying classifiers and hubs constitutes a resource to unravel candidate BM stromal mediators.

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A correlation network with predictor genes for the BM HSPC-supportive stromal niche

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An information theoretic network for the supportive perivascular stromal niche

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Wnt facilitator Rspo2 together with SCF to amplify ex vivo hematopoietic precursors

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Resource combining bioinformatics algorithms to search for novel stromal mediators

Telocytes inhibited inflammatory factor expression and enhanced cell migration in LPS-induced skin wound healing models in vitro and in vivo

Background

Cell proliferation and death are key components of wound healing and tissue repair. Telocytes (TCs) represent a newly discovered cell type that can protect tissue from acute injury via cell–cell communication with adjacent cells. The aim of this study was to use a mouse model of skin wound healing and lipopolysaccharide (LPS)-induced cell injury to evaluate the effects of TCs on skin wound healing in vivo and in vitro.

Material/methods

Immunohistochemical staining was performed to evaluate the alteration of TCs in tissues from normal and chronic wound patients. Then, a male C57BL/6 mouse wound model of the back was established. The mice were divided randomly into three groups, and wound healing was estimated according to the wound healing rate and histology. An LPS-induced co-culture model of a mouse lung telocyte cell line (TCs) with human keratinocyte (HaCaT), human dermal microvascular endothelial cell (HDMEC) or murine fibroblast (L929) cell lines was established to analyse the effects of TCs on constitutive cell types of the skin. Cell proliferation, migration and apoptosis were examined, and reactive oxygen species (ROS) and inflammatory factors in HaCaT cells, HDMECs, and L929 cells were detected to study the mechanisms involved in TC protection in skin wounds.

Results

TCs were significantly increased in tissues from chronic wound patients compared with healthy controls. Wound healing was significantly improved in wound mouse models treated with exogenous TCs compared with LPS-induced models. TCs reversed the LPS-induced inhibition of HaCaT cells and HDMECs and reduced the LPS-induced apoptosis of HaCaT cells and the death ratios of HDMECs and L929 cells. TCs reversed LPS-induced ROS in HDMECs and L929 cells and decreased inflammatory factor mRNA levels in HaCaT cells, HDMECs and L929 cells.

Conclusions

TCs reduce wound healing delay, and inflammatory responses caused by LPS might be mediated by inflammatory inhibition, thus restricting apoptosis and promoting migration of the main component cell types in the skin.

Roles of transforming growth factor-β and phosphatidylinositol 3-kinase isoforms in integrin β1-mediated bio-behaviors of mouse lung telocytes

Background

Telocytes (TCs) have the capacity of cell–cell communication with adjacent cells within the tissue, contributing to tissue repair and recovery from injury. The present study aims at investigating the molecular mechanisms by which the TGFβ1-ITGB1-PI3K signal pathways regulate TC cycle and proliferation.

Methods

Gene expression of integrin (ITG) family were measured in mouse primary TCs to compare with other cells. TC proliferation, movement, cell cycle, and PI3K isoform protein genes were assayed in ITGB1-negative or positive mouse lung TCs treated with the inhibition of PI3Kp110α, PI3Kα/δ, PKCβ, or GSK3, followed by TGFβ1 treatment.

Results

We found the characters and interactions of ITG or PKC family member networks in primary mouse lung TCs, different from other cells in the lung tissue. The deletion of ITGB1 changed TCs sensitivity to treatment with multifunctional cytokines or signal pathway inhibitors. The compensatory mechanisms occur among TGFβ1-induced PI3Kp110α, PI3Kα/δ, PKCβ, or GSK3 when ITGB1 gene was deleted, leading to alterations of TC cell cycle and proliferation. Of those PI3K isoform protein genes, mRNA expression of PIK3CG altered with ITGB1-negative TC cycle and proliferation.

Conclusion

TCs have strong capacity of proliferation through the compensatory signaling mechanisms and contribute to the development of drug resistance due to alterations of TC sensitivity.

The regulatory effect of microRNA-21a-3p on the promotion of telocyte angiogenesis mediated by PI3K (p110α)/AKT/mTOR in LPS induced mice ARDS

Background

Telocytes (TCs) are newly identified interstitial cells that participate in tissue protection and repair. The present study investigated the mechanisms underlying the protective effect of TCs in a mouse model of respiratory distress.

Methods

The mouse model of acute respiratory distress syndrome (ARDS) was established by intratracheal instillation of lipopolysaccharide (LPS). After instillation of TCs culture medium, lung injury was assessed, and angiogenesis markers, including CD31 and endothelial nitric oxide synthase (eNOS), were detected by immunofluorescence. Bioinformatics analysis was used to screen significantly differentially expressed microRNAs (miRNAs) in cultured TCs stimulated with LPS, and the regulation of downstream angiogenesis genes by these miRNAs was analysed and verified. PI3K subunits and pathways were evaluated by using a PI3K p110α inhibitor to study the involved mechanisms.

Results

In ARDS mice, instillation of TCs culture medium ameliorated LPS-induced inflammation and lung injury and increased the protein levels of CD31 and eNOS in the injured lungs. A total of 7 miRNAs and 1899 mRNAs were differentially regulated in TCs stimulated with LPS. Functional prediction analysis showed that the differentially expressed mRNAs were enriched in angiogenesis-related processes, which were highly correlated with miR-21a-3p. Culture medium from TCs with miR-21a-3p inhibition failed to promote angiogenesis in mouse models of LPS-induced ARDS. In cultured TCs, LPS stimulation upregulated the expression of miR-21a-3p, which further targeted the transcription factor E2F8 and decreased Notch2 protein expression. TCs culture medium enhanced hemangioendothelioma endothelial cells (EOMA cells) proliferation, which was blocked by the miR-21a-3p inhibitor. The PI3K p110α inhibitor decreased vascular endothelial growth factor levels in LPS-stimulated TCs and reversed the enhancing effect of TCs culture medium on EOMA cells proliferation.

Conclusions

TCs exerted protective effects under inflammatory conditions by promoting angiogenesis via miR-21a-3p. The PI3K p110α subunit and transcriptional factor E2F8 could be involved in this process.

Roles of TGFβ1 in the expression of phosphoinositide 3-kinase isoform genes and sensitivity and response of lung telocytes to PI3K inhibitors

BACKGROUND

The mouse lung telocyte cell line (TC^SV40) recently established provides further opportunities to learn TC biology and functions. The present study aims at investigating regulatory roles of phosphoinositide 3-kinase (PI3K) isoforms in TC proliferation and movement and in TGFβ1-induced sensitivity and response of lung TCs to PI3K inhibitors.

MATERIALS AND METHODS

Network and molecular interactions of genes coding PI3K family or TGFβ family proteins in mouse primary TCs were defined. Mouse lung TC^SV40 proliferation, apoptosis, cell cycle, and dynamical bio-behaviors were measured with or without TGFβ1 stimulation or PI3K catalytic isoform protein (PI3K/mTOR, PI3Kα/δ/β, PI3K p110δ, or pan-PI3K) inhibitions.

RESULTS

The present study showed the difference of network characteristics and interactions of genes coding PI3K isoform proteins or TGFβ family proteins in primary lung telocytes from mouse lungs compared to those of other cells residing in the lung. TGFβ1 had diverse effects on TC proliferation with altered TC number in G2 or S phase, independent upon the administered dose of TGFβ1. PI3Kα/δ/β, PI3K/mTOR, and PI3K p110δ were involved in TC proliferation, of which PI3Kα/δ/β was more sensitive. The effects of pan-PI3K inhibitor indicate that more PI3K isoforms were stimulated by the administering of external TGFβ1 and contributed to TGFβ1-induced TC proliferation. PI3K p110δ upregulated TC proliferation and movement dynamically without TGFβ1, and downregulated TC proliferation with TGFβ1 stimulation, but not TC movement. PI3Kα/δ/β and PI3K/mTOR were more active in TGFβ1-induced S phase accumulation and had similar dynamic effects to PI3K p110δ. Gene expression of PI3K isoforms in TCs was upregulated after TGFβ1 stimulation. The expression of PIK3CA coding p110-α or PIK3CG coding p110-γ were up- or downregulated in TCs without TGFβ1, respectively, when PI3K/mTOR, PI3Kα/δ/β, PI3K p110δ, or pan-PI3K were inhibited. TGFβ1 upregulated the expression of PIK3CA and PIK3CB, while downregulated the expression of PIK3CD and PIK3CG.

CONCLUSION

Our data imply that TGFβ1 plays divergent roles in the expression of PI3K isoform genes in lung TCs and can alter the sensitivity and response of lung TCs to PI3K inhibitors.