Properties of porcine adipose-derived stem cells and their applications in preclinical models

Effect of metabolically divergent pig breeds and tissues on mesenchymal stem cell expression patterns during adipogenesis

BACKGROUND

Unraveling the intricate and tightly regulated process of adipogenesis, involving coordinated activation of transcription factors and signaling pathways, is essential for addressing obesity and related metabolic disorders. The molecular pathways recruited by mesenchymal stem cells (MSCs) during adipogenesis are also dependent on the different sources of the cells and genetic backgrounds of donors, which contribute to the functional heterogeneity of the stem cells and consequently affect the developmental features and fate of the cells.

METHODS

In this study, the alteration of transcripts during differentiation of synovial mesenchymal stem cells (SMSCs) derived from fibrous synovium (FS) and adipose synovial tissue (FP) of two pig breeds differing in growth performance (German Landrace (DL)) and fat deposition (Angeln Saddleback (AS)) was investigated. SMSCs from both tissues and breeds were stimulated to differentiate into adipocytes in vitro and sampled at four time points (day 1, day 4, day 7 and day 14) to obtain transcriptomic data.

RESULTS

We observed numerous signaling pathways related to the cell cycle, cell division, cell migration, or cell proliferation during early stages of adipogenesis. As the differentiation process progresses, cells begin to accumulate intracellular lipid droplets and changes in gene expression patterns in particular of adipocyte-specific markers occur. PI3K-Akt signaling and metabolic pathways changed most during adipogenesis, while p53 signaling and ferroptosis were affected late in adipogenesis. When comparing MSCs from FS and FP, only a limited number of differentially expressed genes (DEGs) and enriched signaling pathways were identified. Metabolic pathways, including fat, energy or amino acid metabolism, were highly enriched in the AS breed SMSCs compared to those of the DL breed, especially at day 7 of adipogenesis, suggesting retention of the characteristic metabolic features of their original source, demonstrating donor memory in culture. In contrast, the DL SMSCs were more enriched in immune signaling pathways.

CONCLUSIONS

Our study has provided important insights into the dynamics of adipogenesis and revealed metabolic shifts in SMSCs associated with different cell sources and genetic backgrounds of donors. This emphasises the critical role of metabolic and genetic factors as important indications and criteria for donor stem cell selection.

Trends of regenerative tissue engineering for oral and maxillofacial reconstruction in veterinary medicine

Oral and maxillofacial (OMF) defects are not limited to humans and are often encountered in other species. Reconstructing significant tissue defects requires an excellent strategy for efficient and cost-effective treatment. In this regard, tissue engineering comprising stem cells, scaffolds, and signaling molecules is emerging as an innovative approach to treating OMF defects in veterinary patients. This review presents a comprehensive overview of OMF defects and tissue engineering principles to establish proper treatment and achieve both hard and soft tissue regeneration in veterinary practice. Moreover, bench-to-bedside future opportunities and challenges of tissue engineering usage are also addressed in this literature review.

Mesenchymal stem cells of Oravka chicken breed: promising path to biodiversity conservation

Mesenchymal stem cells (MSCs) are multilineage cells able to differentiate into other cell types. MSCs derived from bone marrow or compact bones are the most accessible stem cells used in tissue engineering. Therefore, the aim of this study was to isolate, characterize and cryopreserve MSCs of endangered Oravka chicken breed. MSCs were obtained from compact bones of the femur and tibiotarsus. MSCs were spindle-shaped and were able to differentiate into osteo-, adipo-, and chondrocytes under the specific differentiation conditions. Furthermore, MSCs were positive for surface markers such as CD29, CD44, CD73, CD90, CD105, CD146 and negative for CD34CD45 by flow cytometry. Moreover, MSCs demonstrated high positivity of "stemness" markers aldehyde dehydrogenase, alkaline phosphatase as well as for intracellular markers vimentin, desmin, α-SMA. Subsequently, MSCs were cryopreserved using 10% dimethyl sulfoxide in liquid nitrogen. Based on the results from the viability, phenotype, and ultrastructure assessment we can concluded that the MSCs were not negatively affected by the cryopreservation. Finally, MSCs of endangered Oravka chicken breed were successfully stored in animal gene bank, thus making them a valuable genetic resource.

Reassessment of adipocyte technology for cellular agriculture of alternative fat

Alternative proteins, such as cultivated meat, have recently attracted significant attention as novel and sustainable food. Fat tissue/cell is an important component of meat that makes organoleptic and nutritional contributions. Although adipocyte biology is relatively well investigated, there is limited focus on the specific techniques and strategies to produce cultivated fat from agricultural animals. In the assumed standard workflow, stem/progenitor cell lines are derived from tissues of animals, cultured for expansion, and differentiated into mature adipocytes. Here, we compile information from literature related to cell isolation, growth, differentiation, and analysis from bovine, porcine, chicken, other livestock, and seafood species. A diverse range of tissue sources, cell isolation methods, cell types, growth media, differentiation cocktails, and analytical methods for measuring adipogenic levels were used across species. Based on our analysis, we identify opportunities and challenges in advancing new technology era toward producing "alternative fat" that is suitable for human consumption.

Stem cells and common biomaterials in dentistry: a review study

Stem cells exist as normal cells in embryonic and adult tissues. In recent years, scientists have spared efforts to determine the role of stem cells in treating many diseases. Stem cells can self-regenerate and transform into some somatic cells. They would also have a special position in the future in various clinical fields, drug discovery, and other scientific research. Accordingly, the detection of safe and low-cost methods to obtain such cells is one of the main objectives of research. Jaw, face, and mouth tissues are the rich sources of stem cells, which more accessible than other stem cells, so stem cell and tissue engineering treatments in dentistry have received much clinical attention in recent years. This review study examines three essential elements of tissue engineering in dentistry and clinical practice, including stem cells derived from the intra- and extra-oral sources, growth factors, and scaffolds.

A Porcine Model Using Adipose Stem Cell-Loaded Scaffolds for Alveolar Ridge Augmentation

Tooth loss greatly affects a person's quality of life and many turn to dental implants to replace lost teeth. The success of a dental implant depends on the amount of alveolar bone supporting the implant, and thus, bone augmentation is often necessary to preserve or build up bone volume in the alveolar ridge. Bone can be augmented with autogenous bone, allografts, or xenografts, but the limitations of such natural bone grafts prompt researchers to develop synthetic scaffolds supplemented with cells and/or bioactive agents as alternative bone grafts. The translation of these combination scaffolds from the laboratory to the clinic requires reliable experimental models that can simulate the clinical conditions in human patients. In this article, we describe the use of a porcine alveolar defect model as a platform to evaluate the efficacy of a novel combination of a three-dimensional-printed polycaprolactone-tricalcium phosphate (PCL-TCP) scaffold and adipose-derived mesenchymal stem cells (AD-MSCs) in lateral alveolar augmentation. The surgical protocol for the defect creation and regenerative surgery, as well as analytical methods to determine the extent of tissue regeneration, are described and discussed.

A New lncRNA, lnc-LLMA, Regulates Lipid Metabolism in Pig Hepatocytes

A large variety of long noncoding RNAs (lncRNAs) have been discovered through high-throughput sequencing technology and some have been demonstrated to play important roles in lipid metabolism regulation. In our study, we found a highly expressed lncRNA (lnc-LLMA, liver lipid metabolism-associated lncRNA) in the liver of Duroc pigs, which was enriched in the nucleus. It displays potent tissue specificity among different pig breeds. Overexpression of lnc-LLMA can cause a decline in intracellular triglyceride (TG) levels and increases in ATP and mitochondrial DNA levels in pig primary hepatocytes and HepG2 cells. In addition, the expression levels of MTTP, APOB, CPT1α, and other genes were increased by overexpression of lnc-LLMA. It downregulated expression of G6Pase and SREBP1 genes. Chromatin isolation by RNA purification (ChRIP) experiments demonstrated that microsomal triglyceride transfer protein (MTTP) and glycogen synthase 2 (GYS2) were the potential interacting proteins of lnc-LLMA. The overexpression of the GYS2 gene rescued the decreasing intracellular TG levels caused by the increase of lnc-LLMA. Similarly, overexpression of MTTP was also able to save the lnc-LLMA-induced decrease in intracellular TG. Our study demonstrated that this novel lncRNA was closely related to lipid metabolism and affected lipid transport and mitochondrial function through MTTP and GYS2. Our results provided a new direction for further studying the effect of lncRNA on lipid metabolism regulation.

The Potential Role of Human NME1 in Neuronal Differentiation of Porcine Mesenchymal Stem Cells: Application of NB-hNME1 as a Human NME1 Suppressor

This study aimed to investigate the effects of the human macrophage (MP) secretome in cellular xenograft rejection. The role of human nucleoside diphosphate kinase A (hNME1), from the secretome of MPs involved in the neuronal differentiation of miniature pig adipose tissue-derived mesenchymal stem cells (mp AD-MSCs), was evaluated by proteomic analysis. Herein, we first demonstrate that hNME1 strongly binds to porcine ST8 alpha-N-acetyl-neuraminide alpha-2,8-sialyltransferase 1 (pST8SIA1), which is a ganglioside GD3 synthase. When hNME1 binds with pST8SIA1, it induces degradation of pST8SIA1 in mp AD-MSCs, thereby inhibiting the expression of ganglioside GD3 followed by decreased neuronal differentiation of mp AD-MSCs. Therefore, we produced nanobodies (NBs) named NB-hNME1 that bind to hNME1 specifically, and the inhibitory effect of NB-hNME1 was evaluated for blocking the binding between hNME1 and pST8SIA1. Consequently, NB-hNME1 effectively blocked the binding of hNME1 to pST8SIA1, thereby recovering the expression of ganglioside GD3 and neuronal differentiation of mp AD-MSCs. Our findings suggest that mp AD-MSCs could be a potential candidate for use as an additive, such as an immunosuppressant, in stem cell transplantation.

Phenotypical Characterization and Neurogenic Differentiation of Rabbit Adipose Tissue-Derived Mesenchymal Stem Cells

Although the rabbit is a frequently used biological model, the phenotype of rabbit adipose-derived mesenchymal stem cells (rAT-MSCs) is not well characterized. One of the reasons is the absence of specific anti-rabbit antibodies. The study aimed to characterize rAT-MSCs using flow cytometry and PCR methods, especially digital droplet PCR, which confirmed the expression of selected markers at the mRNA level. A combination of these methods validated the expression of MSCs markers (CD29, CD44, CD73, CD90 and CD105). In addition, cells were also positive for CD49f, vimentin, desmin, α-SMA, ALDH and also for the pluripotent markers: NANOG, OCT4 and SOX2. Moreover, the present study proved the ability of rAT-MSCs to differentiate into a neurogenic lineage based on the confirmed expression of neuronal markers ENO2 and MAP2. Obtained results suggest that rAT-MSCs have, despite the slight differences in marker expression, the similar phenotype as human AT-MSCs and possess the neurodifferentiation ability. Accordingly, rAT-MSCs should be subjected to further studies with potential application in veterinary medicine but also, in case of their cryopreservation, as a source of genetic information of endangered species stored in the gene bank.

Morphological and Molecular Features of Porcine Mesenchymal Stem Cells Derived From Different Types of Synovial Membrane, and Genetic Background of Cell Donors

Synovial mesenchymal stem cells (SMSCs) have become a great cell source for musculoskeletal stem cell research, especially related to cartilage and bone tissue regeneration, due to their superior cell proliferation properties and multidifferentiation potential into various cell lineages. This study revealed isolation methods, culture conditions, and morphological and molecular characterization of SMSCs derived fibrous synovium (FS) and adipose synovium (FP) of two pig breeds differing in growth performance [German Landrace (DL), and fat deposition (Angeln Saddleback (AS)]. Herein, FS possessed nucleated cell numbers nearly twice as high as those of FP at Passage 0. SMSCs derived from different types of synovial membrane and genetic background show similar cell morphologies and immunophenotypes, which were assessed by cell surface epitopes and multilineage differentiation potential, but differ significantly in their molecular characteristics. In addition, transcripts of SMSCs from AS were more enriched in IGF-1 signaling and VEGF ligand receptor, while SMSCs from DL were more enriched in growth hormone signaling and bone metabolism. The results indicate that genetics and tissues play significant roles for SMSC characteristics so that SMSCs can be traced back to the original cell donor and be used for fine turning in applications of medical research and therapies.

Riboflavin-UVA crosslinking of amniotic membranes and its influence on the culture of adipose-derived stem cells

The human amniotic membrane (hAM) is a collagen-based extracellular matrix whose applications are restricted by its moderate mechanical properties and rapid biodegradation. In this work, we investigate the use of riboflavin, a water-soluble vitamin, to crosslink and strengthen the human amniotic membrane under UVA light. The effect of riboflavin-UVA crosslinking on hAM properties were determined via infrared spectroscopy, uniaxial tensile testing, proteolytic degradation, permeability testing, SEM, and quantification of free (un-crosslinked) amine groups. Samples crosslinked with glutaraldehyde, a common and effective yet cytotoxic crosslinking agent, were used as controls. Improved hAM mechanical properties must not come at the expense of reduced cellular proliferation and induction capabilities. In this study, we assessed the viability, proliferation, immunophenotype, and multilineage differentiation ability of human adipose-derived stem cells seeded on riboflavin-UVA crosslinked membranes. Overall, hAM crosslinked with riboflavin-UVA benefited from a stable three-fold increase in mechanical properties (comparable to the increase seen with glutaraldehyde crosslinked membranes) and improved biodegradation, all while retaining their biocompatibility and abilities to support the cultivation and differentiation of adipose-derived stem cells. Together, these results suggest that riboflavin-UVA crosslinking is an effective strategy to enhance the hAM for tissue engineering and regenerative medicine applications establishing it as an attractive and tuneable biomaterial.

Physioxia: a more effective approach for culturing human adipose-derived stem cells for cell transplantation

Background

Although typically cultured at an atmospheric oxygen concentration (20–21%), adipose-derived stem cells (ASCs) reside under considerable low oxygen tension (physioxia) in vivo. In the present study, we explored whether and how physioxia could be a more effective strategy for culturing ASCs for transplantation.

Methods

After isolation, human ASCs were cultured under physioxia (2% O₂) and hyperoxia (20% O₂) until assayed. WST-8, Transwell, tube formation, β-galactosidase staining, and annexin V-FITC/PI assays were used to evaluate cell proliferation, migration, angiogenesis, senescence, and apoptosis, respectively. Survivability was determined by an ischemia model in vitro and nude mouse model in vivo, and the underlying metabolic alterations were investigated by fluorescence staining, flow cytometry, and real-time polymerase chain reaction.

Results

Compared with those in the hyperoxia group, cells in the physioxia group exhibited increased proliferation, migration, and angiogenesis, and decreased senescence and apoptosis. The increased survival rate of ASCs cultured in physioxia was found both in ischemia model in vitro and in vivo. The underlying metabolic reprogramming was also monitored and showed decreased mitochondrial mass, alkalized intracellular pH, and increased glucose uptake and glycogen synthesis.

Conclusions

These results suggest that physioxia is a more effective environment in which to culture ASCs for transplantation owing to the maintenance of native bioactivities without injury by hyperoxia.

Urine-Derived Stem Cells: The Present and the Future

Stem cell research provides promising strategies in improving healthcare for human beings. As a noninvasively obtained and easy-to-culture cell resource with relatively low expense, urine-derived stem cells have special advantages. They have been extensively studied on its proliferation ability and differentiation potential and were being reprogrammed to model diseases during the last decade. In this review, we intend to summarize the latest progress on the research of urine-derived stem cells for its broad application mainly in regenerative medicine and disease modeling, as well as in what is challenging currently. This minireview will highlight the potential application of urine-derived stem cells and provides possible direction of further research in the future.