Perivascular Mesenchymal Stem/Stromal Cells, an Immune Privileged Niche for Viruses?

Surface modification of decellularized kidney scaffold with chemokine and AKI-CKD cytokine juice to increase the recellularization efficiency of bio-engineered kidney

Chronic kidney disease (CKD) is a prevalent global health issue, primarily caused by glomerular dysfunction, diabetes, endovascular disorders, hypertensive nephrosclerosis, and other vascular diseases. Despite the increase in available organ sources, significant challenges remain in securing organ compatibility, prompting extensive research into creating a bio-artificial kidney free from immune rejection. In this study, a bio-engineered kidney was established using a stem cell chemoattractant within a bioreactor system; rBMSCs were used to recellularize the decellularized kidney scaffold coated with SDF-1α/AKI-CKD cytokine juice under mimic-hypoxic conditions as these chemokines and cytokines are crucial for the cell migration. LC-MS/MS proteomic analysis of the scaffold suggested that it contains various important proteins related to angiogenesis, cell migration, differentiation, etc. The in-silico binding simulation and Immunohistochemical (IHC) staining were utilized to detect the coated chemokines and cytokines. Cells were administered through both ureter and arterial routes of the kidney scaffold to differentiate into epithelial and endothelial cells. After 14 days of the recellularization process utilizing a mimic-hypoxia-induced bioreactor, the SDF-1α/AKI-CKD CJ-coated kidney scaffold exhibited high levels of cell attachment, migration, and proliferation in both the cortex and medulla. Additionally, the coating of the cytokines remarkably enhanced the expression of specific renal cell markers within the complex microfilter-like tubular structures. This study underscores a recellularization strategy that addresses the challenges associated with constructing bio-artificial kidneys and contributes to the growing field of bio-artificial organ research.

Eosinophilic esophagitis drives tissue fibroblast regenerative programs toward pathologic dysfunction

BACKGROUND

Pathologic tissue remodeling with scarring and tissue rigidity has been demonstrated in inflammatory, autoimmune, and allergic diseases. Eosinophilic esophagitis (EoE) is an allergic disease that is diagnosed and managed by repeated biopsy procurement, allowing an understanding of tissue fibroblast dysfunction. While EoE-associated tissue remodeling causes clinical dysphagia, food impactions, esophageal rigidity, and strictures, molecular mechanisms driving these complications remain under investigation.

OBJECTIVE

We hypothesized that chronic EoE inflammation induces pathogenic fibroblasts with dysfunctional tissue regeneration and motility.

METHODS

We used single-cell RNA sequencing, fluorescence-activated cell sorting analysis, and fibroblast differentiation and migration assays to decipher the induced and retained pathogenic dysfunctions in EoE versus healthy esophageal fibroblasts.

RESULTS

Differentiation assays demonstrated that active EoE fibroblasts retain regenerative programs for rigid cells such as chondrocytes (P < .05) but lose healthy fibroblast capacity for soft cells such as adipocytes (P < .01), which was reflected in biopsy sample immunostaining (P < .01). EoE, but not healthy, fibroblasts show proinflammatory and prorigidity transcriptional programs on single-cell RNA sequencing. In vivo, regenerative fibroblasts reside in perivascular regions and near the epithelial junction, and during EoE, they have significantly increased migration (P < .01). Flow analysis and functional assays demonstrated that regenerative EoE fibroblasts have decreased surface CD73 expression and activity (both P < .05) compared to healthy controls, indicating aberrant adenosine triphosphate handling. EoE fibroblast dysfunctions were induced in healthy fibroblasts by reducing CD73 activity and rescued in EoE using adenosine repletion.

CONCLUSION

A normalization of perturbed extracellular adenosine triphosphate handling and CD73 could improve pathogenic fibroblast dysfunction and tissue regeneration in type 2 inflammatory diseases.

Exosome-Mediated Antigen Delivery: Unveiling Novel Strategies in Viral Infection Control and Vaccine Design

Exosomes are small subtypes of extracellular vesicles (EVs) naturally released by different types of cells into their environment. Their physiological roles appear to be multiple, yet many aspects of their biological activities remain to be understood. These vesicles can transport and deliver a variety of cargoes and may serve as unconventional secretory vesicles. Thus, they play a crucial role as important vectors for intercellular communication and the maintenance of homeostasis. Exosome production and content can vary under several stresses or modifications in the cell microenvironment, influencing cellular responses and stimulating immunity. During infectious processes, exosomes are described as double-edged swords, displaying both beneficial and detrimental effects. Owing to their tractability, the analysis of EVs from multiple biofluids has become a booming tool for monitoring various pathologies, from infectious to cancerous origins. In this review, we present an overview of exosome features and discuss their particular and ambiguous functions in infectious contexts. We then focus on their properties as diagnostic or therapeutic tools. In this regard, we explore the capacity of exosomes to vectorize immunogenic viral antigens and their function in mounting adaptive immune responses. As exosomes provide interesting platforms for antigen presentation, we further review the available data on exosome engineering, which enables peptides of interest to be exposed at their surface. In the light of all these data, exosomes are emerging as promising avenues for vaccine strategies.

Immune Privileges as a Result of Mutual Regulation of Immune and Stem Systems

Immune privileges of cancer stem cells is a well-known and widely studied problem, as presence of such cells in tumors is associated with refractoriness, recurrence, and metastasis. Accumulating evidence also suggests presence of immune privileges in non-pathological stem cells in addition to their other defense mechanisms against damaging factors. This similarity between pathological and normal stem cells raises the question of why stem cells have such a potentially dangerous property. Regulation of vital processes of autoimmunity control and regeneration realized through interactions between immune cells, stem cells, and their microenvironment are reviewed in this work as causes of formation of the stem cell immune privilege. Deep mutual integration between regulations of stem and immune cells is noted. Considering diversity and complexity of mutual regulation of stem cells, their microenvironment, and immune system, I suggest the term "stem system".

The Dual Role of Mesenchymal Stem Cells in Cancer Pathophysiology: Pro-Tumorigenic Effects versus Therapeutic Potential

Mesenchymal stem/stromal cells (MSCs) are multipotent cells involved in numerous physiological events, including organogenesis, the maintenance of tissue homeostasis, regeneration, or tissue repair. MSCs are increasingly recognized as playing a major, dual, and complex role in cancer pathophysiology through their ability to limit or promote tumor progression. Indeed, these cells are known to interact with the tumor microenvironment, modulate the behavior of tumor cells, influence their functions, and promote distant metastasis formation through the secretion of mediators, the regulation of cell-cell interactions, and the modulation of the immune response. This dynamic network can lead to the establishment of immunoprivileged tissue niches or the formation of new tumors through the proliferation/differentiation of MSCs into cancer-associated fibroblasts as well as cancer stem cells. However, MSCs exhibit also therapeutic effects including anti-tumor, anti-proliferative, anti-inflammatory, or anti-oxidative effects. The therapeutic interest in MSCs is currently growing, mainly due to their ability to selectively migrate and penetrate tumor sites, which would make them relevant as vectors for advanced therapies. Therefore, this review aims to provide an overview of the double-edged sword implications of MSCs in tumor processes. The therapeutic potential of MSCs will be reviewed in melanoma and lung cancers.

Herpes Simplex Virus Infection Alters the Immunological Properties of Adipose-Tissue-Derived Mesenchymal-Stem Cells

The proper functioning of mesenchymal stem cells (MSCs) is of paramount importance for the homeostasis of the body. Inflammation and infection can alter the function of MSCs, which can also affect the regenerative potential and immunological status of tissues. It is not known whether human herpes simplex viruses 1 and 2 (HSV1 and HSV2), well-known human pathogens that can cause lifelong infections, can induce changes in MSCs. In non-healing ulcers, HSV infection is known to affect deeper tissue layers. In addition, HSV infection can recur after initially successful cell therapies. Our aim was to study the response of adipose-derived MSCs (ADMSCs) to HSV infection in vitro. After confirming the phenotype and differentiation capacity of the isolated cells, we infected the cells in vitro with HSV1-KOS, HSV1-532 and HSV2 virus strains. Twenty-four hours after infection, we examined the gene expression of the cells via RNA-seq and RT-PCR; detected secreted cytokines via protein array; and determined autophagy via Western blot, transmission electron microscopy (TEM) and fluorescence microscopy. Infection with different HSV strains resulted in different gene-expression patterns. In addition to the activation of pathways characteristic of viral infections, distinct non-immunological pathways (autophagy, tissue regeneration and differentiation) were also activated according to analyses with QIAGEN Ingenuity Pathway Analysis, Kyoto Encyclopedia of Genes and Genome and Genome Ontology Enrichment. Viral infections increased autophagy, as confirmed via TEM image analysis, and also increased levels of the microtubule-associated protein light chain 3 (LC3B) II protein. We identified significantly altered accumulation for 16 cytokines involved in tissue regeneration and inflammation. Our studies demonstrated that HSV infection can alter the viability and immunological status of ADMSCs, which may have implications for ADMSC-based cell therapies. Alterations in autophagy can affect numerous processes in MSCs, including the inhibition of tissue regeneration as well as pathological differentiation.

On the origin and development of glioblastoma: multifaceted role of perivascular mesenchymal stromal cells

Glioblastoma, IDH wild-type is the most common and aggressive form of glial tumors. The exact mechanisms of glioblastoma oncogenesis, including the identification of the glioma-initiating cell, are yet to be discovered. Recent studies have led to the hypothesis that glioblastoma arises from neural stem cells and glial precursor cells and that cell lineage constitutes a key determinant of the glioblastoma molecular subtype. These findings brought significant advancement to the comprehension of gliomagenesis. However, the cellular origin of glioblastoma with mesenchymal molecular features remains elusive. Mesenchymal stromal cells emerge as potential glioblastoma-initiating cells, especially with regard to the mesenchymal molecular subtype. These fibroblast-like cells, which derive from the neural crest and reside in the perivascular niche, may underlie gliomagenesis and exert pro-tumoral effects within the tumor microenvironment. This review synthesizes the potential roles of mesenchymal stromal cells in the context of glioblastoma and provides novel research avenues to better understand this lethal disease.

Exosomes from Hair Follicle Epidermal Neural Crest Stem Cells Promote Acellular Nerve Allografts to Bridge Rat Facial Nerve Defects

Previous studies showed that acellular nerve allografts (ANAs) have been successfully utilized in repairing peripheral nerve defects, and exosomes produced by stem cells are useful in supporting axon regrowth after peripheral nerve injury. In this study, exosomes from hair follicle epidermal neural crest stem cells (EPI-NCSCs-Exos) combined with ANAs were used to bridge facial nerve defects. EPI-NCSCs-Exos were isolated by ultracentrifuge, and were identified. After coculture, EPI-NCSCs-Exos were internalized into dorsal root ganglions (DRGs) and schwann cells (SCs) in vitro, respectively. EPI-NCSCs-Exos elongate the length of axons and dendrites of DRGs, and accelerated the proliferation and migration of SCs, and increased neurotrophic factor expression of SCs as well. The next step was to assign 24 Sprague Dawley male rats randomly and equally into three groups: the autograft group, the ANA group, and the ANA + EPI-NCSCs-Exos group. Each rat manufactured a 5-mm gap of facial nerve defect and immediately bridged by the corresponding transplants, respectively. After surgery, behavioral changes and electrophysiological testing of each rat were observed and assessed. At 90 days postoperatively, the retrogradely fluorescent tracer-labeled neurons were successfully observed on the injured side in the three groups. Morphological changes of facial nerve regeneration were evaluated by transmission electron microscopy and semithin toluidine blue staining. The results showed that nerve fiber density, nerve fiber diameter, and myelin sheath thickness in the ANA group were significantly worse than those in the other two groups (P < 0.05). No significant difference in nerve fiber density and myelin sheath thickness was observed between the autograft group and the ANA + EPI-NCSCs-Exos group (P = 0.14; P = 0.23). Our data indicated that EPI-NCSCs-Exos facilitate ANAs to bridge facial nerve defects and have the potential to replace autograft therapy in clinic.