Exosomes rewire the cartilage microenvironment in osteoarthritis:from intercellular communication to therapeutic strategies

Osteoarthritis(OA)is a prevalent degenerative joint disease characterized by cartilage loss and accounts for a major source of pain and disability worldwide.However,effective strategies for cartilage repair are lacking,and patients with advanced OA usually need joint replacement.Better comprehending OA pathogenesis may lead to transformative therapeutics.Recently studies have reported that exosomes act as a new means of cell-to-cell communication by delivering multiple bioactive molecules to create a particular microenvironment that tunes cartilage behavior.Specifically,exosome cargos,such as noncoding RNAs(ncRNAs)and proteins,play a crucial role in OA progression by regulating the proliferation,apoptosis,autophagy,and inflammatory response of joint cells,rendering them promising candidates for OA monitoring and treatment.This review systematically summarizes the current insight regarding the biogenesis and function of exosomes and their potential as therapeutic tools targeting cell-to-cell communication in OA,suggesting new realms to improve OA management.

Connexin 43-modified bone marrow stromal cells reverse the imatinib resistance of K562 cells via Ca^(2+)-dependent gap junction intercellular communication

Background: Imatinib mesylate (IM) resistance is an emerging problem for chronic myeloid leukemia (CML). Previous studies found that connexin 43 (Cx43) deficiency in the hematopoietic microenvironment (HM) protects minimal residual disease (MRD), but the mechanism remains unknown. Methods: Immunohistochemistry assays were employed to compare the expression of Cx43 and hypoxia-inducible factor 1α (HIF-1α) in bone marrow (BM) biopsies of CML patients and healthy donors. A coculture system of K562 cells and several Cx43-modified bone marrow stromal cells (BMSCs) was established under IM treatment. Proliferation, cell cycle, apoptosis, and other indicators of K562 cells in different groups were detected to investigate the function and possible mechanism of Cx43. We assessed the Ca^(2+)-related pathway by Western blotting. Tumor-bearing models were also established to validate the causal role of Cx43 in reversing IM resistance. Results: Low levels of Cx43 in BMs were observed in CML patients, and Cx43 expression was negatively correlated with HIF-1α. We also observed that K562 cells cocultured with BMSCs transfected with adenovirus-short hairpin RNA of Cx43 (BMSCs-shCx43) had a lower apoptosis rate and that their cell cycle was blocked in G0/G1 phase, while the result was the opposite in the Cx43-overexpression setting. Cx43 mediates gap junction intercellular communication (GJIC) through direct contact, and Ca ^(2+ )is the key factor mediating the downstream apoptotic pathway. In animal experiments, mice bearing K562, and BMSCs-Cx43 had the smallest tumor volume and spleen, which was consistent with the in vitro experiments. Conclusions: Cx43 deficiency exists in CML patients, promoting the generation of MRD and inducing drug resistance. Enhancing Cx43 expression and GJIC function in the HM may be a novel strategy to reverse drug resistance and promote IM efficacy.

Single-cell profiling reveals Müller glia coordinate retinal intercellular communication during light/dark adaptation via thyroid hormone signaling

Light adaptation enables the vertebrate visual system to operate over a wide range of ambient illumination.Regulation of phototransduction in photoreceptors is considered a major mechanism underlying light adaptation.However,various types of neurons and glial cells exist in the retina,and whether and how all retinal cells interact to adapt to light/dark conditions at the cellular and molecular levels requires systematic investigation.Therefore,we utilized single-cell RNA sequencing to dissect retinal cell-type-specific transcriptomes during light/dark adaptation in mice.The results demonstrated that,in addition to photoreceptors,other retinal cell types also showed dynamic molecular changes and specifically enriched signaling pathways under light/dark adaptation.Importantly,Müller glial cells(MGs)were identified as hub cells for intercellular interactions,displaying complex cell‒cell communication with other retinal cells.Furthermore,light increased the transcription of the deiodinase Dio2 in MGs,which converted thyroxine(T4)to active triiodothyronine(T3).Subsequently,light increased T3 levels and regulated mitochondrial respiration in retinal cells in response to light conditions.As cones specifically express the thyroid hormone receptor Thrb,they responded to the increase in T3 by adjusting light responsiveness.Loss of the expression of Dio2 specifically in MGs decreased the light responsive ability of cones.These results suggest that retinal cells display global transcriptional changes under light/dark adaptation and that MGs coordinate intercellular communication during light/dark adaptation via thyroid hormone signaling.

Single-cell manipulation by two-dimensional micropatterning

Cells are highly sensitive to their geometrical and mechanical microenvironment that directly regulate cell shape,cytoskeleton and organelle,as well as the nucleus morphology and genetic expression.The emerging two-dimensional micropatterning techniques offer powerful tools to construct controllable and well-organized microenvironment for single-cell level investigations with qualitative analysis,cellular standardization,and in vivo environment mimicking.Here,we provide an overview of the basic principle and characteristics of the two most widely-used micropatterning techniques,including photolithographic micropatterning and soft lithography micropatterning.Moreover,we summarize the application of micropatterning technique in controlling cytoskeleton,cell migration,nucleus and gene expression,as well as intercellular communication.

Single-cell analysis of cellular heterogeneity and interactions in the ischemia-reperfusion injured mouse intestine

Nine major cell populations among 46,716 cells were identified in mouse intestinal ischemia‒reperfusion(II/R)injury by single-cell RNA sequencing.For enterocyte cells,11 subclusters were found,in which enterocyte cluster 1(EC1),enterocyte cluster 3(EC3),and enterocyte cluster 8(EC8)were newly discovered cells in ischemia 45 min/reperfusion 720 min(I 45 min/R 720 min)group.EC1 and EC3 played roles in digestion and absorption,and EC8 played a role in cell junctions.For TA cells,after ischemia 45 min/reperfusion 90 min(I 45 min/R 90 min),many TA cells at the stage of proliferation were identified.For Paneth cells,Paneth cluster 3 was observed in the resting state of normal jejunum.After I 45 min/R 90 min,three new subsets were found,in which Paneth cluster 1 had good antigen presentation activity.The main functions of goblet cells were to synthesize and secrete mucus,and a novel subcluster(goblet cluster 5)with highly proliferative ability was discovered in I 45 min/R 90 min group.As a major part of immune system,the changes in T cells with important roles were clarified.Notably,enterocyte cells secreted Guca2b to interact with Gucy2c receptor on the membranes of stem cells,TA cells,Paneth cells,and goblet cells to elicit intercellular communication.One marker known as glutathione S-transferase mu 3(GSTM3)affected intestinal mucosal barrier function by adjusting mitogen-activated protein kinases(MAPK)signaling during II/R injury.The data on the heterogeneity of intestinal cells,cellular communication and the mechanism of GSTM3 provide a cellular basis for treating II/R injury.

Connexin 40-formed GJIC increases the phototoxicity of photodynamic therapy through ROS-and calcium-mediated pathways

OBJECTIVE To explore the effect of connexin(Cx)40-formed gap junctional intercellular communication(GJIC)on Photofrin-photodynamic therapy(PDT)phototoxicity in Cx40-transfected He La cells and its potential mechanisms.METHODS He La cell line stably transfected to express Cx40 was seeded at high and low cell density,respectively,to assess in vitro photosensitivity using CCK8 assay.Western blot assay was performed to detect the expression of Cx40.The intracellular ROS and Ca^(2+) concentrations were determined using flow cytometer.4-HNE and ceramide were measured using ELISA assay.RESULTS Cx40-composed GJ formation at high density enhances the phototoxicity of PhotofrinPDT.When the Cx40 is not expressed or Cx40 channels are blocked,the phototoxicity in high-density cultures substantially reduces,indicating that the enhanced PDT phototoxicity at high density is mediated by Cx40-composed GJIC.The GJIC-mediated increase in PDT phototoxicity was associated with ROS and calcium-mediated stress signaling pathways.CONCLUSION The work uniquely presents the ability of Cx40-composed GJIC to enhance the sensitivity of malignant cells to PDT,and indicates that maintenance or increase of Cx40-formed GJIC may be a profitable strategy towards the enhancement of PDT therapeutic efficiency.

The effect of exosomes in transferring TET signaling alterations

Ten eleven translocation(TET)enzymes are composed of three representatives:TET1/2/3 which are involved in the hydroxymethylation of methylated cytosines.Because of the wide array of processes that are governed by these epigenetic marks,there have been a wide range of clinical effects associated with TET alterations.Even though many research groups have focused on analyzing the effect of TET alterations within certain cells,few have taken into consideration the effect of TET in the context of intercellular communication.One important entity through which intercellular communication occurs is represented by exosomes.Thus,in the current viewpoint we discussed the direct transfer of TET by exosomes,its alterations in the cell targeted by exosomes and the effect of TET alterations on exosome secretion.

Energy intake,metabolic homeostasis,and human health

The energy substances(mainly carbohydrates and fats)are the basis and guarantee of life activity,especially the oxidative phosphorylation for energy supply.However,excessive absorption and accumulation of these substances can lead to metabolic diseases such as obesity,hyperlipidemia,diabetes,and cancers.A large amount of studies demonstrate that G protein-coupled receptors(GPCRs)play a key role in identification and absorption of energy substances,and the signaling network of nerves,immune,and endocrine regulates their storage and utilization.The gastrointestinal mucus layer not only identifies these substances through identification in diet components but also transfers immune,metabolic,and endocrine signals of hormones,cytokines,and chemokines by promoting interactions between receptors and ligands.These signaling molecules are transferred to corresponding organs,tissues,and cells by the circulatory system,and cell activity is regulated by amplifying of cell signals that constitute the wireless communication network among cells in the body.Absorption,accumulation,and utilization of energy substances in the body obey the law of energy conservation.Energy is stored in the form of fat,and meets the demand of body via two coupled mechanisms:catabolism and oxidative phosphorylation.Under normal physiological conditions,fat consumption involves ketone body metabolism through the circulatory system and glucose consumption requires blood lactic acid cycle.Accumulation of excessive energy leads to the abnormal activation of mammalian target of rapamycin(mTOR),thus promoting the excretion of glucose or glycogen in the form of blood glucose and urine glucose.Alternatively,the body cancels the intercellular contact inhibition and promotes cell proliferation to induce carcinogenesis,which can induce the consumption of large amounts of glucose.Intercellular communication is performed by signaling molecules via sensing,absorption,accumulation,and utilization of energy substances,and anabolism and catabolism are controlled by the central metabolic pathway.Therefore,slower catabolism will result in longer life expectancy,whereas faster catabolism results in shorter life expectancy.Energy substances in diet influence the balance between energy and metabolism in the body through the sensing function of the gastrointestinal system at two levels:cellular communication network and metabolic network.The present review of studies aims to strengthen our knowledge on cellular communication and metabolic networks to offer a dietary guidance on the metabolism and communication role of various foods.

Exosomes Derived from Hydroquinone-transformed Human Bronchial Epithelial Cells Inhibited Recipient Cell Apoptosis by transferring miR-221

Objective Although benzene is a confirmed environmental carcinogen,the mechanism of its carcinogenicity remains largely unclear.The suggested oncogene,miR-221,is elevated and plays important roles in various tumors,but its role in benzene-induced carcinogenesis remains unknown.Methods In the present study,we constructed hydroquinone(HQ,a representative metabolite of benzene with biological activity)-transformed malignant cell line(16 HBE-t)and analyzed the level of miR-221 in it with qRT-PCR.Exosomes from 16 HBE-t cells incubated with or without an miR-221 inhibitor were isolated by ultracentrifugation,characterized by transmission electron microscopy and laser scanning confocal microscope,and then transfected into 16 HBE cells.The effects of exosomal miR-221 on apoptosis induced by HQ in recipient cells were determined using flow cytometry.Results The amount of miR-221 in 16 HBE-t was significantly increased compared with controls.When recipient cells ingested exosomes derived from 16 HBE-t,miR-221 was increased,and apoptosis induced by HQ was inhibited.Blocking miR-221 in 16 HBE-t using an inhibitor did not significantly alter miR-221 or apoptosis in recipient cells.Conclusion Exosomal miR-221 secreted by 16 HBE-t inhibits apoptosis induced by HQ in normal recipient cells.

Trends in the biological functions and medical applications of extracellular vesicles and analogues

Natural extracellular vesicles(EVs)play important roles in many life processes such as in the intermolecular transfer of substances and genetic information exchanges.Investigating the origins and working mechanisms of natural EVs may provide an understanding of life activities,especially regarding the occurrence and development of diseases.Additionally,due to their vesicular structure,EVs(in small molecules,nucleic acids,proteins,etc.)could act as efficient drug-delivery carriers.Herein,we describe the sources and biological functions of various EVs,summarize the roles of EVs in disease diagnosis and treatment,and review the application of EVs as drug-delivery carriers.We also assess the challenges and perspectives of EVs in biomedical applications.