Supportive Microenvironment Research Articles

Elevated hematopoietic stem cell frequency in mouse alveolar bone marrow.

Hematopoietic stem cells (HSCs) are crucial for maintaining hematopoietic homeostasis and are localized within distinct bone marrow (BM) niches. While BM niches are often considered similar across different skeletal sites, we discovered that the alveolar BM (al-BM) in the mandible harbors the highest frequency of immunophenotypic HSCs in nine different skeletal sites. Transplantation assays revealed significantly increased engraftment from al-BM compared to femur, tibia, or pelvis BM, likely due to a higher proportion of alveolar HSCs. Moreover, hematopoietic progenitor cells (c-Kit+ Sca-1+ Lin-) in al-BM exhibited increased quiescence and reduced apoptosis, indicating superior maintenance and survival characteristics. We also observed an enrichment of mesenchymal stromal cells and skeletal stem cells in al-BM, suggesting a more supportive microenvironment. These findings indicate that al-BM provides a unique microenvironment conducive to higher frequency of HSCs, offering new insights into site-specific hematopoiesis.

The impact of mechanical tuning on the printability of decellularized amniotic membrane bioinks for cell-laden bioprinting of soft tissue constructs

Decellularized extracellular matrix (dECM) bioinks hold significant potential in the 3D bioprinting of tissue-engineered constructs (TECs). While 3D bioprinting allows for the creation of custom-designed TECs, the development of bioinks based solely on dAM, without the inclusion of supporting agents or chemical modifications, remains underexplored. In this study, we present the concentration-dependent printability and rheological properties of dAM bioinks, along with an analysis of their in vitro cellular responses. Our findings demonstrate that increasing dAM concentrations, within the range of 1 to 3% w/v, enhances the mechanical moduli of the bioinks, enabling the 3D printing of flat structures with superior shape fidelity. In vitro assays reveal high cell viability across all dAM bioink formulations; however, at 3% w/v, the bioink tends to impede fibroblast proliferation, resulting in round cell morphology. We propose that bioinks containing 2% w/v dAM strike an optimal balance, providing fine-resolved features and a supportive microenvironment for fibroblasts, promoting elongated spindle-like morphology and enhanced proliferation. These results underscore the importance of dAM concentration in regulating the properties and performance of bioinks, particularly regarding cell viability and morphology, for the successful 3D bioprinting of soft tissues.

Effect of hyaluronic acid on the formation of acellular dermal matrix-based interpenetrating network sponge scaffolds for accelerating diabetic wound healing through photothermal warm bath

Adequate vascularization essential for delivering nutrients critical to wound healing, yet impaired angiogenesis is a major barrier in diabetic wound repair. This study investigates the impact of hyaluronic acid on interpenetrating network sponge scaffolds derived from an acellular dermal matrix, with the aim of enhancing vascularization and healing of diabetic wounds via photothermal warm bath therapy. We prepared three-dimensional porous sponges (H1P4D2@DFO) using molecular interpenetration and ion crosslinking of porcine acellular dermal matrix (PADM), hyaluronic acid, and polydopamine nanoparticles loaded with deferoxamine mesylate (PDA@DFO). This resulting extracellular matrix-based sponge demonstrated properties suitable for wound repair, including high cell adhesion, biocompatibility, bioactivity, porosity (85 %), and water absorption (4500 %). The near-infrared (NIR) photothermal effect of PDA@DFO and the sustained release of deferoxamine mesylate (DFO) enhanced wound vascularization within the wound site. These findings suggest that our sponge scaffold can simulate skin-like structures and establish a supportive microenvironment conducive to microvascular reconstruction. By combining the photothermal warm bath approach with the scaffold's tailored 3D structure, we observed enhanced angiogenesis and accelerated diabetic wound healing, indicating potential clinical applications of these scaffolds in chronic wound management.

A 3D Nerve Guidance Conduit Surface With a Wrinkled Protein Coating Toward Peripheral Nerve Injury Repair

ABSTRACTPeripheral nerve injuries (PNIs) resulting in myelin breakdown and axonal degeneration at both the proximal and distal nerve stumps are major clinical concerns that can induce functional loss and diminished quality of life. In biomaterials science, considerable attention has been given to artificial nerve guidance conduits (NGCs), since the engineered tubular structures have the potential to supply a supportive nerve microenvironment to longitudinally align the regenerating axons for bridging the injured nerve sites. Although NGCs may become promising alternatives to nerve autografts, the fabrication approaches available to incorporate directional cues for dictating neuronal behavior and nerve reconnection have been limited to conventional micro/nano‐fabrication techniques that are complex and time‐consuming due to manual processing steps. Thus, our goal here was to develop a simple manufacturing approach for introducing topographical cues onto NGCs. To achieve this goal, we used an established mechanically actuated silk wrinkling approach to create topographically functionalized surfaces as a potential NGC material platform for guided directional alignment of neurons. We 3D‐printed thermo‐responsive shape‐memory polymer (SMP)‐based NGCs that can produce silk fibroin (SF)‐wrinkled topographies on the micro and nano‐meter length scale. Since SF is a commonly used biomaterial surface coating with excellent neuro‐compatibility, we studied the ability to develop NGCs that can autonomously actuate silk wrinkles upon heat‐induced contraction of the SMP and evaluated the effects of the topographically functionalized construct on neuronal behavior. Using an immortalized dorsal root ganglion neuronal cell line, we found that the silk‐wrinkled conduits displayed high neuronal viability and adhesion compared to uncoated conduits and tissue‐culture polystyrene controls. We also found that the wrinkled conduits enabled the neurons to elongate and align parallel to the direction of the wrinkled topography. Longer neurite extension was also observed on the wrinkled conduits compared to their respective controls. These findings demonstrate the potential for functional wrinkled protein coatings to provide directional cues in the fabrication of artificial NGCs for peripheral nerve repair.

Dynamic evolution of fibroblasts revealed by single cell RNA sequencing of human pancreatic cancer.

Cancer progression and response to therapy are inextricably reliant on the co-evolution of a supportive tissue microenvironment. This is particularly evident in pancreatic ductal adenocarcinoma (PDAC), a tumor type characterized by expansive and heterogeneous stroma. Herein, we employed single cell RNAseq and spatial transcriptomics of normal, inflamed, and malignant pancreatic tissues to contextualize stromal dynamics associated with disease and treatment status, identifying temporal and spatial trajectories of fibroblast differentiation. Using analytical tools to infer cellular communication, together with a newly developed assay to annotate genomic alterations in cancer cells, we additionally explored the complex intercellular networks underlying tissue circuitry, highlighting a fibroblast-centric interactome that grows in strength and complexity in the context of malignant transformation. Our study yields new insights on the stromal remodeling events favoring the development of a tumor-supportive microenvironment and provides a powerful resource for the exploration of novel points of therapeutic intervention in PDAC.

The Application of Biomaterial-Based Spinal Cord Tissue Engineering.

Advancements in biomaterial-based spinal cord tissue engineering technology have profoundly influenced regenerative medicine, providing innovative solutions for both spinal cord organoid development and engineered spinal cord injury (SCI) repair. In spinal cord organoids, biomaterials offer a supportive microenvironment that mimics the natural extracellular matrix, facilitating cell differentiation and organization and advancing the understanding of spinal cord development and pathophysiology. Furthermore, biomaterials are essential in constructing engineered spinal cords for SCI repair. The incorporation of biomaterials with growth factors, fabrication of ordered scaffold structures, and artificial spinal cord assemblies are critical insights for SCI to ensure structural integrity, enhance cell viability, and promote neural regeneration in transplantation. In summary, this review summarizes the contribution of biomaterials to the spinal cord organoids progression and discusses strategies for biomaterial-based spinal cord engineering in SCI therapy. These achievements underscore the transformative potential of biomaterials to improve treatment options for SCI and accelerate future clinical applications.

Fish collagen sponge with human umbilical cord mesenchymal stem cells for diabetic wound repair in rats.

Stem cell therapy offers a novel approach to treating difbetic foot ulcers. Fish skin decellularized matrix, a type I collagen, provides a promising carrier for stem cells, creating a supportive microenvironment that enhances cell survival and therapeutic potential. This study aims to investigate the effects and mechanisms of human umbilical cord mesenchymal stem cells (HUCMSCs) loaded onto a fish collagen sponge for wound healing in diabetic rats. The study evaluates stem cell-loading efficiency with fish collagen sponge in vitro, assesses material distribution on diabetic rat wounds, and establishes a wound model. Rats are divided into the Self-healing group, Fish collagen sponge group, and Sponge loaded with HUCMSCs group. Therapeutic effects are evaluated through various analyses, including histopathology and reverse transcription polymerase chain reaction for collagen-related gene expression levels. Compared to the self-healing group, both the fish collagen group and the composite group show faster wound repair and improved healing outcomes. The composite group exhibits superior wound healing quality, with fish collagen contributing to enhanced tissue regeneration through collagen regulation at the wound site. Loading HUCMSCs onto a fish collagen sponge shows promise for treating diabetic wounds by addressing nutrient deficiency and cell supply issues, offering potential benefits for patients undergoing treatment.

Targeting the bone marrow niche, moving towards leukemia eradication

Hematopoiesis is a complex and tightly regulated process that drives the formation of mature blood cells from a single hematopoietic stem cell. This complex process occurs within the bone marrow, which, once disrupted or deregulated, subverts normal hematopoietic development, allowing leukemic cells to emerge, proliferate, and thrive. Notably, several cellular populations and paracrine factors within the bone marrow fuel leukemia expansion and progression. This review presents an overview of the main microenvironmental components that promote myeloid leukemia progression, discussing the emerging therapeutical strategies that target both leukemic cells and the supportive bone marrow microenvironment – targeting both the seed and the soil.

Influence of Gelatin on Adhesion, Proliferation, and Adipogenic Differentiation of Adipose Tissue-Derived Stem Cells Cultured on Soy Protein-Agarose Scaffolds.

Scaffolds play a key role in cultured meat production by providing an optimal environment for efficient cell attachment, growth, and development. This study investigated the effects of gelatin coating on the adhesion, proliferation, and adipogenic differentiation of adipose tissue-derived stem cells (ADSCs) cultured on soy protein-agarose scaffolds. Gelatin-coated scaffolds were prepared using 0.5% and 1.0% (w/v) gelatin solutions. The microstructure, water absorption rate, mechanical strength, cytotoxicity, cell adhesion, proliferation, and differentiation capabilities of the scaffolds were analyzed. Field emission scanning electron microscopy revealed the porous microstructure of the scaffolds, which was suitable for cell growth. Gelatin-coated scaffolds exhibited a significantly higher water absorption rate than that of non-coated scaffolds, indicating increased hydrophilicity. In addition, gelatin coating increased the mechanical strength of the scaffolds. Gelatin coating did not show cytotoxicity but significantly enhanced cell adhesion and proliferation. The gene expression levels of peroxisome proliferator-activated receptor gamma, CCAT/enhancer-binding protein alpha, and fatty acid-binding protein 4 were upregulated, and lipid accumulation was increased by gelatin coating. These findings suggest that gelatin-coated scaffolds provide a supportive microenvironment for ADSC growth and differentiation, highlighting their potential as a strategy for the improvement of cultured meat production and adipose tissue engineering.

Core-Shell Gel Nanofiber Scaffolds Constructed by Microfluidic Spinning toward Wound Repair and Tissue Regeneration.

Growing demand for wound care resulting from the increasing chronic diseases and trauma brings intense pressure to global medical health service system. Artificial skin provides mechanical and microenvironmental support for wound, which is crucial in wound healing and tissue regeneration. However, challenges still remain in the clinical application of artificial skin since the lack of the synergy effect of necessary performance. In this study, a multi-functional artificial skin is fabricated through microfluidic spinning technology by using core-shell gel nanofiber scaffolds (NFSs). This strategy can precisely manipulate the microstructure of artificial skin under microscale. The as-prepared artificial skin demonstrates superior characteristics including surface wettability, breathability, high mechanical strength, strain sensitivity, biocompatibility and biodegradability. Notably, this artificial skin has the capability to deliver medications in a controlled and sustained manner, thereby accelerating the wound healing process. This innovative approach paves the way for the development of a new generation of artificial skin and introduces a novel concept for the structural design of the unique core-shell gel NFSs.

Hydrogels for Neural Regeneration: Exploring New Horizons.

Nerve injury can significantly impair motor, sensory, and autonomic functions. Understanding nerve degeneration, particularly Wallerian degeneration, and the mechanisms of nerve regeneration is crucial for developing effective treatments. This manuscript reviews the use of advanced hydrogels that have been researched to enhance nerve regeneration. Hydrogels, due to their biocompatibility, tunable properties, and ability to create a supportive microenvironment, are being explored for their effectiveness in nerve repair. Various types of hydrogels, such as chitosan-, alginate-, collagen-, hyaluronic acid-, and peptide-based hydrogels, are discussed for their roles in promoting axonal growth, functional recovery, and myelination. Advanced formulations incorporating growth factors, bioactive molecules, and stem cells show significant promise in overcoming the limitations of traditional therapies. Despite these advancements, challenges in achieving robust and reliable nerve regeneration remain, necessitating ongoing research to optimize hydrogel-based interventions for neural regeneration.

CD163+ macrophages in mantle cell lymphoma induce activation of prosurvival pathways and immune suppression

AbstractMantle cell lymphoma (MCL) is dependent on a supportive tumor immune microenvironment (TIME) in which infiltration of CD163+ macrophages has a negative prognostic impact. This study explores how abundance and spatial localization of CD163+ cells are associated with the biology of MCL, using spatial multiomic investigations of tumor and infiltrating CD163+ and CD3+ cells. A total of 63 proteins were measured using GeoMx digital spatial profiling in tissue microarrays from 100 diagnostic MCL tissues. Regions of interest were selected in tumor-rich and tumor-sparse tissue regions. Molecular profiling of CD163+ macrophages, CD20+ MCL cells, and CD3+ T-cells was performed. To validate protein profiles, 1811 messenger RNAs were measured in CD20+ cells and 2 subsets of T cells. Image analysis was used to extract the phenotype and position of each targeted cell, thereby allowing the exploration of cell frequencies and cellular neighborhoods. Proteomic investigations revealed that CD163+ cells modulate their immune profile depending on their localization and that the immune inhibitory molecules, V-domain immunoglobulin suppressor of T-cell activation and B7 homolog 3, have higher expression in tumor-sparse than in tumor-rich tissue regions and that targeting should be explored. We showed that MCL tissues with more abundant infiltration of CD163+ cells have a higher proteomic and transcriptional expression of key components of the MAPK pathway. Thus, the MAPK pathway may be a feasible therapeutic target in patients with MCL with CD163+ cell infiltration. We further showed the independent and combined prognostic values of CD11c and CD163 beyond established risk factors.

Hyperbaric Oxygen Therapy as a Novel Approach to Modulating Macrophage Polarization for the Treatment of Glioblastoma.

Glioblastoma multiforme (GBM) is a highly aggressive brain cancer with a poor prognosis despite current treatments. This is partially attributed to the immunosuppressive environment facilitated by tumor-associated macrophages, which predominantly underlie the tumor-promoting M2 phenotype. This study investigated the potential of hyperbaric oxygen (HBO) therapy, traditionally used to treat conditions such as decompression sickness, in modulating the macrophage phenotype toward the tumoricidal M1 state and disrupting the supportive tumor microenvironment. HBO has direct antiproliferative effects on tumor cells and reduces hypoxia, which may impair angiogenesis and tumor growth. This offers a novel approach to GBM treatment by targeting the role of the immune system within the tumor microenvironment. The effects of HBO on macrophage polarization and GBM cell viability and apoptosis were evaluated in this study. We detected that HBO promoted M1 macrophage cytokine expression while decreasing GBM cell viability and increasing apoptosis using GBM cell lines and THP-1-derived macrophage-conditioned media. These findings suggest that HBO therapy can shift macrophage polarization toward a tumoricidal M1 state. This can improve GBM cell survival and offers a potential therapeutic strategy. In conclusion, HBO can shift macrophages from a tumor-promoting M2 phenotype to a tumoricidal M1 phenotype in GBM. This can facilitate apoptosis and, in turn, improve treatment outcomes.

3D bioprinted mesenchymal stem cell laden scaffold enhances subcutaneous vascularization for delivery of cell therapy

Subcutaneous delivery of cell therapy is an appealing minimally-invasive strategy for the treatment of various diseases. However, the subdermal site is poorly vascularized making it inadequate for supporting engraftment, viability, and function of exogenous cells. In this study, we developed a 3D bioprinted scaffold composed of alginate/gelatin (Alg/Gel) embedded with mesenchymal stem cells (MSCs) to enhance vascularization and tissue ingrowth in a subcutaneous microenvironment. We identified bio-ink crosslinking conditions that optimally recapitulated the mechanical properties of subcutaneous tissue. We achieved controlled degradation of the Alg/Gel scaffold synchronous with host tissue ingrowth and remodeling. Further, in a rat model, the Alg/Gel scaffold was superior to MSC-embedded Pluronic hydrogel in supporting tissue development and vascularization of a subcutaneous site. While the scaffold alone promoted vascular tissue formation, the inclusion of MSCs in the bio-ink further enhanced angiogenesis. Our findings highlight the use of simple cell-laden degradable bioprinted structures to generate a supportive microenvironment for cell delivery.Graphical

The Role of Macrophages in Nerve Regeneration: Polarization and Combination with Tissue Engineering.

Peripheral nerve regeneration after trauma poses a substantial clinical challenge that has already been investigated for many years. Infiltration of immune cells is a critical step in the response to nerve damage that creates a supportive microenvironment for regeneration. In this work, we focus on a special type of immune cell, macrophage, in addressing the problem of neuronal regeneration. We discuss the complex endogenous mechanisms of peripheral nerve injury and regrowth vis-à-vis macrophages, including their recruitment, polarization, and interplay with Schwann cells post-trauma. Furthermore, we elucidate the underlying mechanisms by which exogenous stimuli govern the above events. Finally, we summarize the necessary roles of macrophages in peripheral nerve lesions and reconstruction. There are many challenges in controlling macrophage functions to achieve complete neuronal regeneration, even though considerable progress has been made in understanding the connection between these cells and peripheral nerve damage.

The generation of islet-like insulin-producing cells from Wharton's jelly-derived mesenchymal stem cells on the PES/fish gelatin scaffold

Diabetes Mellitus (DM) disrupts the body's capability to control blood glucose statuses. Type 1 diabetes mellitus (T1DM) arises from inadequate insulin production and is treated with insulin replacement therapy. Stem cell therapy is a hopeful treatment for T1DM that involves using adult stem cells to generate insulin-producing cells (IPCs). Mesenchymal stem cells (MSCs) are particularly advantageous for generating IPCs. The islet cells require interactions with the extracellular matrix for survival, which is lacking in conventional 2D culture systems. Natural or synthetic polymers create a supportive 3D microenvironment in tissue engineering. We aim to construct superior differentiation conditions employing polyethersulfone (PES)/Fish gelatin scaffolds to differentiate Wharton's jelly-derived mesenchymal stem cells (WJ-MSCs) to IPCs. In this study, the PES/fish gelatin scaffold (3D) was manufactured by electrospinning, and then its biocompatibility and non-toxicity were investigated by MTT assay. After that, scaffold-supportive effects on WJ-MSCs differentiation to IPCs were studied at the gene and protein levels. After exposure to the differentiation media, 2D and 3D (PES/Fish gelatin) cultured cells were slowly aggregated and developed spherical-shaped clusters. The viability of cells was found to be comparable in both 2D and 3D cultures. The gene expression analysis showed that efficiency of differentiation was more elevated in 3D culture. Additionally, ELISA results indicated that C-peptide and insulin release were more significant in 3D than in 2D culture. In conclusion, the PES/fish gelatin scaffold is highly promising for pancreatic tissue engineering because it supports the viability, growth, and differentiation of WJ-MSCs into IPCs.

Macrophages Orchestrate the Liver Tumor Microenvironment.

Liver cancer is one of the leading causes of cancer-related mortality. Hepatocellular carcinoma and cholangiocarcinoma are the most common types, and despite numerous advances, therapeutic options still remain poor for these cancer patients. Tumor development and progression strictly depend on a supportive tumor microenvironment (TME). Tumor-associated macrophages (TAMs) are the most abundant immune cells population within a tumorigenic liver; they sustain cancer cells' growth and invasiveness, and their presence is correlated with a poor prognosis. Furthermore, TAM cross-talk with cells and components of the TME promotes immunosuppression, a desmoplastic response, and angiogenesis. In this review, we summarize the latest advances in understanding TAM heterogeneity and function, with a particular focus on TAM modulation of the TME. We also discuss the potential of targeting macrophage subpopulations and how this is now being exploited in current clinical trials for the treatment of liver cancer.

LEAP-014: first-line lenvatinib+ pembrolizumab+chemotherapy in advanced/metastatic esophageal squamous cell carcinoma.

Treatment options for patients with advanced or metastatic esophageal squamous cell carcinoma (ESCC) are improving. Current guidelines recommend first-line pembrolizumab plus chemotherapy for patients with unresectable or metastatic ESCC, which has led to improvements in survival outcomes. Antiangiogenic therapy combined with immune checkpoint inhibitors can act synergistically to convert the immunosuppressive tumor microenvironment to an immune supportive microenvironment, thus enhancing antitumor immune responses. In preclinical models, the antiangiogenic agent lenvatinib combined with an anti-PD-1 agent showed synergistic antitumor activity. We describe the design and rationale for the randomized, open-label, phase III LEAP-014 study of lenvatinib in combination with pembrolizumab plus chemotherapy in patients with advanced or metastatic ESCC. Overall survival and progression-free survival are the dual primary end points.Clinical Trial Registration: NCT04949256 (ClinicalTrials.gov).

A vascularized breast cancer spheroid platform for the ranked evaluation of tumor microenvironment-targeted drugs by light sheet fluorescence microscopy

Targeting the supportive tumor microenvironment (TME) is an approach of high interest in cancer drug development. However, assessing TME-targeted drug candidates presents a unique set of challenges. We develop a comprehensive screening platform that allows monitoring, quantifying, and ranking drug-induced effects in self-organizing, vascularized tumor spheroids (VTSs). The confrontation of four human-derived cell populations makes it possible to recreate and study complex changes in TME composition and cell-cell interaction. The platform is modular and adaptable for tumor entity or genetic manipulation. Treatment effects are recorded by light sheet fluorescence microscopy and translated by an advanced image analysis routine in processable multi-parametric datasets. The system proved to be robust, with strong interassay reliability. We demonstrate the platform’s utility for evaluating TME-targeted antifibrotic and antiangiogenic drugs side-by-side. The platform’s output enabled the differential evaluation of even closely related drug candidates according to projected therapeutic needs.

A multistep computational approach reveals a neuro-mesenchymal cell population in the embryonic hematopoietic stem cell niche.

The first hematopoietic stem and progenitor cells (HSPCs) emerge in the Aorta-Gonad-Mesonephros (AGM) region of the mid-gestation mouse embryo. However, the precise nature of their supportive mesenchymal microenvironment remains largely unexplored. Here, we profiled transcriptomes of laser micro-dissected aortic tissues at three developmental stages and individual AGM cells. Computational analyses allowed the identification of several cell subpopulations within the E11.5 AGM mesenchyme, with the presence of a yet unidentified subpopulation characterized by the dual expression of genes implicated in adhesive or neuronal functions. We confirmed the identity of this cell subset as a neuro-mesenchymal population, through morphological and lineage tracing assays. Loss of function in the zebrafish confirmed that Decorin, a characteristic extracellular matrix component of the neuro-mesenchyme, is essential for HSPC development. We further demonstrated that this cell population is not merely derived from the neural crest, and hence, is a bona fide novel subpopulation of the AGM mesenchyme.