Stem Cell-Derived Exosomes as a Therapeutic Option for Spinal Cord Injuries; a Systematic Review and Meta-Analysis.

Introduction: Exosomes function as cell signaling carriers and have drawn much attention to the cell-free treatments of regenerative medicine. This meta-analysis aimed to investigate the efficacy of mesenchymal stem cell-derived (MSC-derived) exosomes in animal models of spinal cord injuries (SCI). Method: A comprehensive search was conducted in Medline, Embase, Scopus, and Web of Science to attain related articles published by January 31, 2023. The eligible keywords were correlated with the spinal cord injury and MSC-derived exosomes. The evaluated outcomes were locomotion, cavity size, cell apoptosis, inflammation, neuro-regeneration, and microglia activation. A standardized mean difference was calculated for each sample and a pooled effect size was reported. Results: 65 papers fully met the inclusion criteria. Treatment with MSC-derived exosomes ultimately improved locomotion and shrunk cavity size (p<0.0001). The administration of MSC-derived exosomes enhanced the expression of beta-tubulin III, NF200, and GAP-43, and increased the number of NeuN-positive and Nissl-positive cells, while reducing the expression of glial fibrillary acidic protein (p<0.0001). The number of apoptotic cells in the treatment group decreased significantly (p<0.0001). Regarding the markers of microglia activation, MSC-derived exosomes increased the number of CD206- and CD68-positive cells (p=0.032 and p<0.0001, respectively). Additionally, MSC-derived exosome administration significantly increased the expression of the anti-inflammatory interleukin (IL)-10 and IL-4 (p<0.001 and p=0.001, respectively) and decreased the expression of the inflammatory IL-1b, IL-6, and TNF-a (p<0.0001). Conclusion: MSC-derived exosome treatment resulted in a significantly improved locomotion of SCI animals through ameliorating neuroinflammation, reducing apoptosis, and inducing neuronal regrowth by facilitating a desirable microenvironment.

Wenshen Xiaozheng Tang alleviates fibrosis in endometriosis by regulating differentiation and paracrine signaling of endometrium-derived mesenchymal stem cells.

ETHNOPHARMACOLOGICAL RELEVANCE: Wenshen Xiaozheng Tang (WXT), a traditional Chinese medicine (TCM) decoction, is effective for treating endometriosis. However, the effect of WXT on endometrium-derived mesenchymal stem cells (eMSCs) which play a key role in the fibrogenesis of endometriosis requires further elucidation. AIMS OF THE STUDY: The aim of this study was to clarify the potential mechanism of WXT in improving fibrosis in endometriosis by investigating the regulation of WXT on differentiation and paracrine of eMSCs. MATERIALS AND METHODS: The nude mice with endometriosis were randomly divided into model group, WXT group and mifepristone group. After 21 days of treatment, the lesion volume was calculated. Fibrosis in the lesions was evaluated by Masson staining and expression of fibrotic proteins. The differentiation of eMSCs in vivo was explored using a fate-tracking experiment. To further clarify the regulation of WXT on eMSCs, primary eMSCs from the ectopic lesions of endometriosis patients were isolated and characterized. The effect of WXT on the proliferation and differentiation of ectopic eMSCs was examined. To evaluate the role of WXT on the paracrine activity of ectopic eMSCs, the conditioned medium (CM) from ectopic eMSCs pretreated with WXT was collected and applied to treat ectopic endometrial stromal cells (ESCs), after which the expression of fibrotic proteins in ectopic ESCs was assessed. In addition, transcriptome sequencing was used to investigate the regulatory mechanism of WXT on ectopic eMSCs, and western blot and ELISA were employed to determine the key mediator. RESULTS: WXT impeded the growth of ectopic lesions in nude mice with endometriosis and reduced collagen deposition and the expression of fibrotic proteins fibronectin, collagen I, α-SMA and CTGF in the endometriotic lesions. The fate-tracking experiment showed that WXT prevented human eMSCs from differentiating into myofibroblasts in the nude mice. We successfully isolated eMSCs from the lesions of patients with endometriosis and demonstrated that WXT suppressed proliferation and myofibroblast differentiation of ectopic eMSCs. Moreover, the expression of α-SMA, collagen I, fibronectin and CTGF in ectopic ESCs was significantly down-regulated by the CM of ectopic MSCs pretreated with WXT. Combining the results of RNA sequencing, western blot and ELISA, we found that WXT not only reduced thrombospondin 4 expression in ectopic eMSCs, but also decreased thrombospondin 4 secretion from ectopic eMSCs. Thrombospondin 4 concentration-dependently upregulated the expression of collagen I, fibronectin, α-SMA and CTGF in ectopic ESCs, indicating that thrombospondin 4 was a key mediator of WXT in inhibiting the fibrotic process in endometriosis. CONCLUSION: WXT improved fibrosis in endometriosis by regulating differentiation and paracrine signaling of eMSCs. Thrombospondin 4, whose release from ectopic eMSCs is inhibited by WXT, may be a potential target for the treatment of endometriosis.

Gradient conducting polymer surfaces with netrin-1-conjugation promote axon guidance and neuron transmission of human iPSC-derived retinal ganglion cells.

Major advances have been made in utilizing human-induced pluripotent stem cells (hiPSCs) for regenerative medicine. Nevertheless, the delivery and integration of hiPSCs into target tissues remain significant challenges, particularly in the context of retinal ganglion cell (RGC) restoration. In this study, we introduce a promising avenue for providing directional guidance to regenerated cells in the retina. First, we developed a technique for construction of gradient interfaces based on functionalized conductive polymers, which could be applied with various functionalized ehthylenedioxythiophene (EDOT) monomers. Using a tree-shaped channel encapsulated with a thin PDMS and a specially designed electrochemical chamber, gradient flow generation could be converted into a functionalized-PEDOT gradient film by cyclic voltammetry. The characteristics of the successfully fabricated gradient flow and surface were analyzed using fluorescent labels, time of flight secondary ion mass spectrometry (TOF-SIMS), and X-ray photoelectron spectroscopy (XPS). Remarkably, hiPSC-RGCs seeded on PEDOT exhibited improvements in neurite outgrowth, axon guidance and neuronal electrophysiology measurements. These results suggest that our novel gradient PEDOT may be used with hiPSC-based technologies as a potential biomedical engineering scaffold for functional restoration of RGCs in retinal degenerative diseases and optic neuropathies.

MSCs biomimetic ultrasonic phase change nanoparticles promotes cardiac functional recovery after acute myocardial infarction.

Acute Myocardial Infarction (AMI) has seen rising cases, particularly in younger people, leading to public health concerns. Standard treatments, like coronary artery recanalization, often don't fully repair the heart's microvasculature, risking heart failure. Advances show that Mesenchymal Stromal Cells (MSCs) transplantation improves cardiac function after AMI, but the harsh microenvironment post-AMI impacts cell survival and therapeutic results. MSCs aid heart repair via their membrane proteins and paracrine extracellular vesicles that carry microRNA-125b, which regulates multiple targets, preventing cardiomyocyte death, limiting fibroblast growth, and combating myocardial remodeling after AMI. This study introduces ultrasound-responsive phase-change bionic nanoparticles, leveraging MSCs' natural properties. These particles contain MSC membrane and microRNA-125b, with added macrophage membrane for stability. Using Ultrasound Targeted Microbubble Destruction (UTMD), this method targets the delivery of MSC membrane proteins and microRNA-125b to AMI's inflamed areas. This aims to enhance cardiac function recovery and provide precise, targeted AMI therapy.

Generating ESC-Derived RGCs for Cell Replacement Therapy.

In several ocular diseases, degeneration of retinal neurons can lead to permanent blindness. Transplantation of stem cell (SC)-derived RGCs has been proposed as a potential therapy for RGC loss. Although there are reports of successful cases of SC-derived RGC transplantation, achieving long-distance regeneration and functional connectivity remains a challenge. To address these hurdles, retinal organoids are being used to study the regulatory mechanism of stem cell transplantation. Here we present a modified protocol for differentiating human embryonic stem cells (ESCs) into retinal organoids and transplanting organoid-derived RGCs into the murine eyes.

Isolation, Culture, and Quality Assessment of Clinical-Grade Corneal Stromal Stem Cells.

The challenge of treating corneal scarring through keratoplasties lies in the limited availability of donor tissue. Various studies have shown the therapeutic use of cultivated corneal stromal stem cells (CSSCs) to mitigate tissue inflammation and suppress fibrosis and scar tissue formation in preclinical corneal wound models. To develop CSSC therapy for clinical trials on patients with corneal scarring, it is necessary to generate clinical-grade CSSCs in compliant to Good Manufacturing Practice (GMP) regulations. This chapter elucidates human CSSC isolation, culture, and cryopreservation under GMP-compliant conditions. It underscores quality assessment encompassing morphological traits, expression of stemness markers, anti-inflammatory activity, and keratocyte differentiation potency.

Trabecular Meshwork Regeneration for Glaucoma Treatment Using Stem Cell-Derived Trophic Factors.

Glaucoma is one of the leading causes of irreversible blindness. Stem cell therapy has shown promise in the treatment of primary open-angle glaucoma in animal models. Stem cell-free therapy using stem cell-derived trophic factors might be in demand in patients with high-risk conditions or religious restrictions. In this chapter, we describe methods for trabecular meshwork stem cell (TMSC) cultivation, secretome harvesting, and protein isolation, as well as assays to ensure the health of TMSC post-secretome harvesting and for secretome periocular injection into mice for therapeutic purposes.

Generation of Induced-Primary Retinal Pigment Epithelium from Human Retinal Organoids.

Retinal pigment epithelium (RPE) cells derived from induced pluripotent stem cells (iPSCs) serve multiple roles, including among others, modeling RPE development in normal and pathological conditions, investigating mechanisms of RPE physiology, modeling retinal diseases involving the RPE, and developing strategies for regenerative therapies. We have developed a simple and efficient protocol to generate RPE tissue from human iPSCs-derived retinal organoids. The RPE tissue present in the retinal organoids is analogous to the native human RPE in differentiation timeline, histological organization, and key features of functional maturation. Building upon this system, we established a method to generate functionally mature, polarized RPE monolayers comparable to human primary RPE. This comprehensive protocol outlines the steps for isolating and culturing RPE tissue using retinal organoids. The outcome is a pure population of cells expressing mature RPE signatures and organized in a characteristic cobblestone monolayer featuring robust ultrastructural polarization. These RPE monolayers also exhibit the functional hallmarks of bona fide mature RPE cells, providing a suitable system to mimic the biology and function of the native human RPE.

Material-driven immunomodulation and ECM remodeling reverse pulmonary fibrosis by local delivery of stem cell-laden microcapsules.

Recent progress in stem cell therapy has demonstrated the therapeutic potential of intravenous stem cell infusions for treating the life-threatening lung disease of pulmonary fibrosis (PF). However, it is confronted with limitations, such as a lack of control over cellular function and rapid clearance by the host after implantation. In this study, we developed an innovative PF therapy through tracheal administration of microfluidic-templated stem cell-laden microcapsules, which effectively reversed the progression of inflammation and fibrotic injury. Our findings highlight that hydrogel microencapsulation can enhance the persistence of donor mesenchymal stem cells (MSCs) in the host while driving MSCs to substantially augment their therapeutic functions, including immunoregulation and matrix metalloproteinase (MMP)-mediated extracellular matrix (ECM) remodeling. We revealed that microencapsulation activates the MAPK signaling pathway in MSCs to increase MMP expression, thereby degrading overexpressed collagen accumulated in fibrotic lungs. Our research demonstrates the potential of hydrogel microcapsules to enhance the therapeutic efficacy of MSCs through cell-material interactions, presenting a promising yet straightforward strategy for designing advanced stem cell therapies for fibrotic diseases.

A cuproptosis-based nanomedicine suppresses triple negative breast cancers by regulating tumor microenvironment and eliminating cancer stem cells.

Cuproptosis is a new kind of cell death that depends on delivering copper ions into mitochondria to trigger the aggradation of tricarboxylic acid (TCA) cycle proteins and has been observed in various cancer cells. However, whether cuproptosis occurs in cancer stem cells (CSCs) is unexplored thus far, and CSCs often reside in a hypoxic tumor microenvironment (TME) of triple negative breast cancers (TNBC), which suppresses the expression of the cuproptosis protein FDX1, thereby diminishing anticancer efficacy of cuproptosis. Herein, a ROS-responsive active targeting cuproptosis-based nanomedicine CuET@PHF is developed by stabilizing copper ionophores CuET nanocrystals with polydopamine and hydroxyethyl starch to eradicate CSCs. By taking advantage of the photothermal effects of CuET@PHF, tumor hypoxia is overcome via tumor mechanics normalization, thereby leading to enhanced cuproptosis and immunogenic cell death in 4T1 CSCs. As a result, the integration of CuET@PHF and mild photothermal therapy not only significantly suppresses tumor growth but also effectively inhibits tumor recurrence and distant metastasis by eliminating CSCs and augmenting antitumor immune responses. This study presents the first evidence of cuproptosis in CSCs, reveals that disrupting hypoxia augments cuproptosis cancer therapy, and establishes a paradigm for potent cancer therapy by simultaneously eliminating CSCs and boosting antitumor immunity.

Transcriptomic profiling of human mesenchymal stem cells using a pulsed electromagnetic-wave motion bioreactor system for enhanced osteogenic commitment and therapeutic potentials.

Traditional bioreactor systems involve the use of three-dimensional (3D) scaffolds or stem cell aggregates, limiting the accessibility to the production of cell-secreted biomolecules. Herein, we present the use a pulse electromagnetic fields (pEMFs)-assisted wave-motion bioreactor system for the dynamic and scalable culture of human bone marrow-derived mesenchymal stem cells (hBMSCs) with enhanced the secretion of various soluble factors with massive therapeutic potential. The present study investigated the influence of dynamic pEMF (D-pEMF) on the kinetic of hBMSCs. A 30-min exposure of pEMF (10V-1Hz, 5.82 G) with 35 oscillations per minute (OPM) rocking speed can induce the proliferation (1 × 105 â†’ 4.5 × 105) of hBMSCs than static culture. Furthermore, the culture of hBMSCs in osteo-induction media revealed a greater enhancement of osteogenic transcription factors under the D-pEMF condition, suggesting that D-pEMF addition significantly boosted hBMSCs osteogenesis. Additionally, the RNA sequencing data revealed a significant shift in various osteogenic and signaling genes in the D-pEMF group, further suggesting their osteogenic capabilities. In this research, we demonstrated that the combined effect of wave and pEMF stimulation on hBMSCs allows rapid proliferation and induces osteogenic properties in the cells. Moreover, our study revealed that D-pEMF stimuli also induce ROS-scavenging properties in the cultured cells. This study also revealed a bioactive and cost-effective approach that enables the use of cells without using any expensive materials and avoids the possible risks associated with them post-implantation.

Efficiently directing differentiation and homing of mesenchymal stem cells to boost cartilage repair in osteoarthritis via a nanoparticle and peptide dual-engineering strategy.

Mesenchymal stem cells (MSCs) are expected to be useful therapeutics in osteoarthritis (OA), the most common joint disorder characterized by cartilage degradation. However, evidence is limited with regard to cartilage repair in clinical trials because of the uncontrolled differentiation and weak cartilage-targeting ability of MSCs after injection. To overcome these drawbacks, here we synthesized CuO@MSN nanoparticles (NPs) to deliver Sox9 plasmid DNA (favoring chondrogenesis) and recombinant protein Bmp7 (inhibiting hypertrophy). After taking up CuO@MSN/Sox9/Bmp7 (CSB NPs), the expressions of chondrogenic markers were enhanced while hypertrophic markers were decreased in response to these CSB-engineered MSCs. Moreover, a cartilage-targeted peptide (designated as peptide W) was conjugated onto the surface of MSCs via a click chemistry reaction, thereby prolonging the residence time of MSCs in both the knee joint cavity of mice and human-derived cartilage. In a surgery-induced OA mouse model, the NP and peptide dual-modified W-CSB-MSCs showed an enhancing therapeutic effect on cartilage repair in knee joints compared with other engineered MSCs after intra-articular injection. Most importantly, W-CSB-MSCs accelerated cartilage regeneration in damaged cartilage explants derived from OA patients. Thus, this new peptide and NPs dual engineering strategy shows potential for clinical applications to boost cartilage repair in OA using MSC therapy.

Multilayered hydrogel scaffold construct with native tissue matched elastic modulus: A regenerative microenvironment for urethral scar-free healing.

The unsuitable deformation stimulus, harsh urine environment, and lack of a regenerative microenvironment (RME) prevent scaffold-based urethral repair and ultimately lead to irreversible urethral scarring. The researchers clarify the optimal elastic modulus of the urethral scaffolds for urethral repair and design a multilayered PVA hydrogel scaffold for urethral scar-free healing. The inner layer of the scaffold has self-healing properties, which ensures that the wound effectively resists harsh urine erosion, even when subjected to sutures. In addition, the scaffold's outer layer has an extracellular matrix-like structure that synergizes with adipose-derived stem cells to create a favorable RME. In vivo experiments confirm successful urethral scar-free healing using the PVA multilayered hydrogel scaffold. Further mechanistic study shows that the PVA multilayer hydrogel effectively resists the urine-induced inflammatory response and accelerates the transition of urethral wound healing to the proliferative phase by regulating macrophage polarization, thus providing favorable conditions for urethral scar-free healing. This study provides mechanical criteria for the fabrication of urethral tissue-engineered scaffolds, as well as important insights into their design.

Stiff extracellular matrix drives the differentiation of mesenchymal stem cells toward osteogenesis by the multiscale 3D genome reorganization.

Extracellular matrix (ECM) stiffness is a major driver of stem cell fate. However, the involvement of the three-dimensional (3D) genomic reorganization in response to ECM stiffness remains unclear. Here, we generated comprehensive 3D chromatin landscapes of mesenchymal stem cells (MSCs) exposed to various ECM stiffness. We found that there were more long-range chromatin interactions, but less compartment A in MSCs cultured on stiff ECM than those cultured on soft ECM. However, the switch from compartment B in MSCs cultured on soft ECM to compartment A in MSCs cultured on stiff ECM included genes encoding proteins primarily enriched in cytoskeleton organization. At the topologically associating domains (TADs) level, stiff ECM tends to have merged TADs on soft ECM. These merged TADs on stiff ECM include upregulated genes encoding proteins enriched in osteogenesis, such as SP1, ETS1, and DCHS1, which were validated by quantitative real-time polymerase chain reaction and found to be consistent with the increase of alkaline phosphatase staining. Knockdown of SP1 or ETS1 led to the downregulation of osteogenic marker genes, including COL1A1, RUNX2, ALP, and OCN in MSCs cultured on stiff ECM. Our study provides an important insight into the stiff ECM-mediated promotion of MSC differentiation towards osteogenesis, emphasizing the influence of mechanical cues on the reorganization of 3D genome architecture and stem cell fate.

Advances in meniscus tissue engineering: Towards bridging the gaps from bench to bedside.

Meniscus is vital for maintaining the anatomical and functional integrity of knee. Injuries to meniscus, commonly caused by trauma or degenerative processes, can result in knee joint dysfunction and secondary osteoarthritis, while current conservative and surgical interventions for meniscus injuries bear suboptimal outcomes. In the past decade, there has been a significant focus on advancing meniscus tissue engineering, encompassing isolated scaffold strategies, biological augmentation, physical stimulus, and meniscus organoids, to improve the prognosis of meniscus injuries. Despite noteworthy promising preclinical results, translational gaps and inconsistencies in the therapeutic efficiency between preclinical and clinical studies exist. This review comprehensively outlines the developments in meniscus tissue engineering over the past decade (Scheme 1). Reasons for the discordant results between preclinical and clinical trials, as well as potential strategies to expedite the translation of bench-to-bedside approaches are analyzed and discussed.

The impact of endocrine-disrupting chemicals on stem cells: Mechanisms and implications for human health.

Endocrine-disrupting chemicals (EDCs) are compounds, either natural or man-made, that interfere with the normal functioning of the endocrine system. There is increasing evidence that exposure to EDCs can have profound adverse effects on reproduction, metabolic disorders, neurological alterations, and increased risk of hormone-dependent cancer. Stem cells (SCs) are integral to these pathological processes, and it is therefore crucial to understand how EDCs may influence SC functionality. This review examines the literature on different types of EDCs and their effects on various types of SCs, including embryonic, adult, and cancer SCs. Possible molecular mechanisms through which EDCs may influence the phenotype of SCs are also evaluated. Finally, the possible implications of these effects on human health are discussed. The available literature demonstrates that EDCs can influence the biology of SCs in a variety of ways, including by altering hormonal pathways, DNA damage, epigenetic changes, reactive oxygen species production and alterations in the gene expression patterns. These disruptions may lead to a variety of cell fates and diseases later in adulthood including increased risk of endocrine disorders, obesity, infertility, reproductive abnormalities, and cancer. Therefore, the review emphasizes the importance of raising broader awareness regarding the intricate impact of EDCs on human health.

Industry updates from the field of stem cell research and regenerative medicine in March 2024.

Latest developments in the field of stem cell research and regenerative medicine compiled from publicly available information and press releases from non-academic institutions in March 2024.

Regenerative medicine industry news digest, March 2024.

[Analysis of the therapeutic effect of avatinib bridged allogeneic hematopoietic stem cell transplantation on 7 cases of recurrent/refractory RUNX1-RUNX1T1 positive acute myeloid leukemia with KIT mutations].

Objective: To evaluate the efficacy of avatinib plus allogeneic hematopoietic stem cell transplantation (allo-HSCT) for the treatment of recurrent/refractory RUNX1-RUNX1T1 positive acute myeloid leukemia (AML) with KIT mutations. Method: A retrospective study was conducted on the clinical data of seven relapsed/refractory AML patients containing the RUNX1-RUNX1T1 fusion gene and KIT mutation who received afatinib plus allo-HSCT treatment at the First Affiliated Hospital of Soochow University from June 2019 to June 2023. Results: The seven AML patients included one male and six females with a median age of 37 (18-56) years. All seven patients had KIT mutations (five positive for D816V and two positive for D816Y) . There were two refractory patients and five relapsed patients (all of whom had bone marrow recurrence) . All patients had to complete at least one course of treatment with afatinib before transplantation. Four patients achieved complete remission (CR) after treatment with afatinib, six patients had negative KIT gene mutations, and one had a decreased KIT gene mutational burden. There were three cases of unrelated identical transplantation and four cases of haploidentical transplantation. All patients received the modified Bu/Cy pretreatment regimen. After transplantation, all patients were successfully implanted and a bone marrow examination showed CR and minimal residual disease turned negative. Five patients exhibited negative fusion genes. Two patients died from infection following transplantation. Conclusion: Afatinib plus allo-HSCT may be an effective and safe new treatment strategy for RUNX1-RUNX1T1 positive AML patients with KIT-D816 mutation.

[The efficacy and safety of avapritinib in the treatment of molecular biologically positive core binding factor-acute myeloid leukemia with KIT mutation after allogeneic hematopoietic stem cell transplantation].

Objective: To investigate the efficacy and safety of avapritinib in the treatment of molecular biologically positive core binding factor-acute myeloid leukemia (CBF-AML) with KIT mutation after allogeneic hematopoietic stem cell transplantation (allo-HSCT) . Methods: We retrospectively analyzed the clinical data of six patients with molecular biologically positive CBF-AML with KIT mutation after allo-HSCT, who were treated with avapritinib at Henan Cancer Hospital from December 2021 to March 2023, and evaluated the efficacy and safety of avapritinib. Results: After 1 month of treatment with avapritinib, the transcription level of the fusion gene decreased in six patients, and the transcription level decreased by ≥1 log in five patients. In four patients who received avapritinib for ≥3 months, the fusion gene turned negative, and the median time to turn negative was 2.0 (range: 1.0-3.0) months. Up to the end of follow-up, four patients had no recurrence. The most common adverse reaction of avapritinib was myelosuppression, including neutropenia in two cases, thrombocytopenia in two cases, and anemia in one case. The non-hematological adverse reactions were nausea in two cases, edema in one case, and memory loss in one case, all of which were grades 1-2. Conclusion: Avapritinib was effective for molecular biologically positive CBF-AML patients with KIT mutation after allo-HSCT. The main adverse reaction was myelosuppression, which could generally be tolerated.

PD-1+ and TIM-3+ T cells widely express common γ-chain cytokine receptors in multiple myeloma patients, and IL-2, IL-7, IL-15 stimulation up-regulates PD-1 and TIM-3 on T cells.

Background: Immune checkpoint ligand-receptor interactions appear to be associated with multiple myeloma (MM) progression. Simultaneously, previous studies showed the possibility of PD-1 and TIM-3 expression on T cells upon stimulation with common γ-chain family cytokines in vitro and during homeostatic proliferation. The aim of the present work was to study the impact of homeostatic proliferation on the expansion of certain T cell subsets up-regulating PD-1 and TIM-3 checkpoint molecules. Methods: The expression of CD25, CD122, CD127 common γ-chain cytokine receptors, phosphorylated signal transducer and activator of transcription-5 (pSTAT5) and eomesodermin (EOMES) was comparatively assessed with flow cytometry in PD-1- and TIM-3-negative and positive T cells before the conditioning and during the first post-transplant month in peripheral blood samples of MM patients. Results: Substantial proportions of PD-1- and TIM-3-positive T lymphocytes expressed common γ-chain cytokine receptors and pSTAT5. Frequencies of cytokine receptor expressing cells were significantly higher within TIM-3+ T cells compared to PD-1+TIM-3- subsets. Considerable proportions of both PD-1-/TIM-3-negative and positive CD8+ T cells express EOMES, while only moderate frequencies of CD4+ PD-1+/TIM-3+ T cells up-regulate this transcription factor. Besides, the surface presence of CD25 and intranuclear expression of EOMES in CD4+ T cells were mutually exclusive regardless of PD-1 and TIM-3 expression. The stimulation with common γ-chain cytokines up-regulates PD-1 and TIM-3 during the proliferation of initially PD-1/TIM-3-negative T cells but fails to expand initially PD-1+ and TIM-3+ T cell subsets in vitro. Conclusions: Both PD-1 and TIM-3 expressing T cells appear to be able to respond to homeostatic cytokine stimulation. Differences in common γ-chain cytokine receptor expression between PD-1+ and TIM-3+ T cells may reflect functional dissimilarity of these cell subsets. Checkpoint blockade appears to alleviate lymphopenia-induced proliferation of PD-1+ T cells but may raise the possibility of immune-mediated adverse events.