Orco-dependent survival of odorant receptor neurons in ants

Olfaction is essential for complex social behavior in insects. To discriminate complex social cues, ants evolved an expanded number of odorant receptor (Or) genes. Mutations in the obligate odorant co-receptor gene orco lead to the loss of ~80% of the antennal lobe glomeruli in the jumping ant Harpegnathos saltator. However, the cellular mechanism remains unclear. Here, we demonstrate massive apoptosis of odorant receptor neurons (ORNs) in the mid to late stages of pupal development, possibly due to ER stress in the absence of Orco. Further bulk and single-nucleus transcriptome analysis shows that, although most orco-expressing ORNs die in orco mutants, a small proportion of them survive: They express ionotropic receptor (Ir) genes that form IR complexes. In addition, we found that some Or genes are expressed in mechanosensory neurons and nonneuronal cells, possibly due to leaky regulation from nearby non-Or genes. Our findings provide a comprehensive overview of ORN development and Or expression in H. saltator.

Comparative cell viability of dentin-bonding adhesive systems on human dental pulp stem cells: time-dependent analysis

BACKGROUND

Restorative materials are in prolonged contact with living tissues such as oral mucosa, dentin, pulp, periodontal, and periapical tissues. Therefore, the potentially harmful effects of these materials and their components on oral tissues should be evaluated before clinical use. This study aimed to compare the cell viability of different adhesive systems (ASs) on human dental pulp stem cells (hDPSCs).

METHODS

Three ASs that combining methacryloyloxydecyl dihydrogen phosphate (MDP) monomer with new hydrophilic amide monomers [Clearfil Universal Bond Quick(CUBQ), Kuraray Noritake], self-reinforcing 3D monomer [Bond Force II(BFII), Tokuyama)], and dual-cure property [Futurabond DC(FBDC), VOCO] were used. Three (n = 3) samples were prepared for each group. Dental pulp stem cells were isolated from ten patients' extracted third molar teeth. Samples were incubated in Dulbecco's modified Eagle's medium (DMEM) for 24 h (h), 72 h, and 7 days (d) to obtain extracts. For the control group, cells were cultured without DBA samples. Cell viability of ASs extracts was measured using a cell proliferation detection kit (WST-1, Roche). Statistical analysis was performed using two-way ANOVA and post-hoc (Duncan) tests (p < 0.05).

RESULTS

At 24 and 72 h statistically significant differences were determined between control and BFII, control and FBDC groups (p < 0.05), while no differences between control and CUBQ groups (p > 0.05). On the 7th d, statistically significant differences were found between the control and experimental groups (p < 0.05), while no differences between experimental groups (p > 0.05). A statistically significant difference was detected for the BFII group over the three-time interval (p < 0.05). The lowest cell viability was observed for the FBDC group at 24 h, and the difference was statistically significant when compared with 72 h and 7th d (p < 0.05).

CONCLUSION

All ASs showed different cell viability values at various exposure times. It should be taken into consideration that pH values, as well as the contents of ASs, have a significant effect on the cell viability.

PRDX1 exerts a photoprotection effect by inhibiting oxidative stress and regulating MAPK signaling on retinal pigment epithelium

BACKGROUND

The purpose of this study was to investigate the photoprotection effect of peroxiredoxin 1 (PRDX1) protein in ultraviolet B (UVB) irradiation-induced damage of retinal pigment epithelium (RPE) and its possible molecular mechanism.

METHODS

ARPE-19 cell viability and apoptosis were assessed by MTT assay and flow cytometry, respectively. Real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to detect the PRDX1 expression. The corresponding kits were employed to measure the levels or activities of lactate dehydrogenase (LDH), 8-hydroxy-2-deoxyguanosine (8-OHdG), reactive oxygen species (ROS), malondialdehyde (MDA), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD). Western blotting was applied to examine PRDX1 expression and mitogen-activated protein kinase (MAPK) signaling pathway-related proteins.

RESULTS

After exposure to 20 mJ/cm2 intensity of UVB irradiation for 24 h, ARPE-19 cells viability was decreased, the leakage degree of LDH and 8-OHdG were increased, and cell apoptosis was elevated. The expression of PRDX1 was significantly down-regulated in UVB-induced ARPE-19 cells. The low expression of PRDX1 was involved in high irradiation intensity. Overexpression of PRDX1 increased cell activity, decreased cell apoptosis, and LDH as well as 8-OHdG leakage in UVB-induced ARPE-19 cells. In addition to alleviating UVB-induced cell damage, PRDX1 overexpression also inhibited UVB-induced oxidative stress (down-regulation of ROS and MDA levels, up-regulation of GSH-Px and SOD activities) and the activation of MAPK signaling pathway in ARPE-19 cells.

CONCLUSION

PRDX1 exerts a photoprotection effect on RPE by attenuating UVB-induced cell damage and inhibiting oxidative stress, which can be attributed to the inhibition of MAPK signaling pathway activation.

Transplantation of dorsal root ganglia overexpressing the NaChBac sodium channel improves locomotion after complete SCI

Spinal cord injury (SCI) is a debilitating condition currently lacking treatment. Severe SCI causes the loss of most supraspinal inputs and neuronal activity caudal to the injury, which, coupled with the limited endogenous capacity for spontaneous regeneration, can lead to complete functional loss even in anatomically incomplete lesions. We hypothesized that transplantation of mature dorsal root ganglia (DRGs) genetically modified to express the NaChBac sodium channel could serve as a therapeutic option for functionally complete SCI. We found that NaChBac expression increased the intrinsic excitability of DRG neurons and promoted cell survival and neurotrophic factor secretion in vitro. Transplantation of NaChBac-expressing dissociated DRGs improved voluntary locomotion 7 weeks after injury compared to control groups. Animals transplanted with NaChBac-expressing DRGs also possessed higher tubulin-positive neuronal fiber and myelin preservation, although serotonergic descending fibers remained unaffected. We observed early preservation of the corticospinal tract 14 days after injury and transplantation, which was lost 7 weeks after injury. Nevertheless, transplantation of NaChBac-expressing DRGs increased the neuronal excitatory input by an increased number of VGLUT2 contacts immediately caudal to the injury. Our work suggests that the transplantation of NaChBac-expressing dissociated DRGs can rescue significant motor function, retaining an excitatory neuronal relay activity immediately caudal to injury.

Effect of storage media on chondrocyte viability during cold storage of osteochondral dowels

Osteochondral allograft transplantation is a successfully proven method to repair articular cartilage defects and prevent the degenerative effects of osteoarthritis. The number of osteochondral transplantations that can be performed each year is limited by availability of donor cartilage tissue and storage time constraints. Osteochondral transplantation success has been linked to high chondrocyte viability of the donor cartilage tissue at the time of implantation. Determining optimal storage conditions for donor cartilage is essential for tissue banks to safely provide quality cartilage tissue. In this study, we compared three tissue/cell media (DMEM/F12, RPMI-1640 and X-VIVO 10) for their ability to maintain chondrocyte viability during hypothermic storage for 28 days. Porcine osteochondral dowels were stored in each media for 28 days and cell viability was assessed every 7 days. Over the 28 day storage period, the chondrocyte viability of dowels stored in DMEM/F12, RPMI-1640, and X-VIVO 10 media all declined in a similar fashion. Our results show that all three media were equivalent in their ability to maintain cell viability of the cartilage tissue and provides rationale for the use of lower cost cell media (DMEM/F12 and RPMI-1640) for hypothermic storage of articular cartilage tissue.

The effects of repeated freezing and thawing on bovine sperm morphometry and function

Refreezing the remaining genetic resources after in vitro fertilization (IVF) can conserve genetic materials. However, the precise damage inflicted by repeated freezing and thawing on bovine sperm and its underlying mechanism remain largely unexplored. Thus, this study investigates the impact of repeated freeze-thaw cycles on sperm. Our findings indicate that such cycles significantly reduce sperm viability and motility. Furthermore, the integrity of the sperm plasma membrane and acrosome is compromised during this process, exacerbating the advanced apoptosis triggered by oxidative stress. Additionally, transmission electron microscopy exposed severe damage to the plasma membranes of both the sperm head and tail. Notably, the "9 + 2" structure of the tail was disrupted, along with a significant decrease in the level of the axonemal protein DNAH10, leading to reduced sperm motility. IVF outcomes revealed that repeated freeze-thaw cycles considerably impair sperm fertilization capability, ultimately reducing the blastocyst rate. In summary, our research demonstrates that repeated freeze-thaw cycles lead to a decline in sperm viability and motility, attributed to oxidative stress-induced apoptosis and DNAH10-related dynamic deficiency. As a result, the utility of semen is compromised after repeated freezing.

Tailoring transfection for cardiomyocyte cell lines: balancing efficiency and toxicity in lipid versus polymer-based transfection methods in H9c2 and HL-1 cells

Cardiovascular research relies heavily on the veracity of in vitro cardiomyocyte models, with H9c2 and HL-1 cell lines at the forefront due to their cardiomyocyte-like properties. However, the variability stemming from nonstandardized culturing and transfection methods poses a significant challenge to data uniformity and reliability. In this study, we introduce meticulously crafted protocols to enhance the culture and transfection of H9c2 and HL-1 cells, emphasizing the reduction of cytotoxic effects while improving transfection efficiency. Through the examination of polymer-based and lipid-based transfection methods, we offer a comparative analysis that underscores the heightened efficiency and reduced toxicity of these approaches. Our research provides an extensive array of step-by-step procedures designed to foster robust cell cultures and outlines troubleshooting practices to rectify issues of low transfection rates. We discuss the merits and drawbacks of both transfection techniques, equipping researchers with the knowledge to choose the most fitting method for their experimental goals. By offering a definitive guide to these cell lines' culturing and transfection, our work seeks to set a new standard in procedural consistency, ensuring that the cardiovascular research community can achieve more dependable and reproducible results, thereby pushing the boundaries of current methodologies toward impactful clinical applications.NEW & NOTEWORTHY We have developed standardized protocols that significantly reduce cytotoxicity and enhance transfection efficiency in H9c2 and HL-1 cardiomyocyte cell lines. Our detailed comparative analysis of polymer-based and lipid-based transfection methods has identified optimized approaches with superior performance. Accompanying these protocols are comprehensive troubleshooting strategies to address common issues related to low transfection rates. Implementing these protocols is expected to yield more consistent and reproducible results, driving the field of cardiovascular research toward impactful clinical breakthroughs.

Mesenchymal stromal cells derived from various tissues: Biological, clinical and cryopreservation aspects: Update from 2015 review

Mesenchymal stromal cells (MSCs) have become one of the most investigated and applied cells for cellular therapy and regenerative medicine. In this update of our review published in 2015, we show that studies continue to abound regarding the characterization of MSCs to distinguish them from other similar cell types, the discovery of new tissue sources of MSCs, and the confirmation of their properties and functions that render them suitable as a therapeutic. Because cryopreservation is widely recognized as the only technology that would enable the on-demand availability of MSCs, here we show that although the traditional method of cryopreserving cells by slow cooling in the presence of 10% dimethyl sulfoxide (Me2SO) continues to be used by many, several novel MSC cryopreservation approaches have emerged. As in our previous review, we conclude from these recent reports that viable and functional MSCs from diverse tissues can be recovered after cryopreservation using a variety of cryoprotectants, freezing protocols, storage temperatures, and periods of storage. We also show that for logistical reasons there are now more studies devoted to the cryopreservation of tissues from which MSCs are derived. A new topic included in this review covers the application in COVID-19 of MSCs arising from their immunomodulatory and antiviral properties. Due to the inherent heterogeneity in MSC populations from different sources there is still no standardized procedure for their isolation, identification, functional characterization, cryopreservation, and route of administration, and not likely to be a "one-size-fits-all" approach in their applications in cell-based therapy and regenerative medicine.

Redifferentiation of genetically modified dedifferentiated chondrocytes in a microcavitary hydrogel

OBJECTIVES

We genetically modified dedifferentiated chondrocytes (DCs) using lentiviral vectors and adenoviral vectors encoding TGF-β3 (referred to as transgenic groups below) and encapsulated these DCs in the microcavitary hydrogel and investigated the combinational effect on redifferentiation of the genetically manipulated DCs.

RESULTS

The Cell Counting Kit-8 data indicated that both transgenic groups exhibited significantly higher cell viability in the first week but inferior cell viability in the subsequent timepoints compared with those of the control group. Real-time polymerase chain reaction and western blot analysis results demonstrated that both transgenic groups had a better effect on redifferentiation to some extent, as evidenced by higher expression levels of chondrogenic genes, suggesting the validity of combination with transgenic DCs and the microcavitary hydrogel on redifferentiation. Although transgenic DCs with adenoviral vectors presented a superior extent of redifferentiation, they also expressed greater levels of the hypertrophic gene type X collagen. It is still worth further exploring how to deliver TGF-β3 more efficiently and optimizing the appropriate parameters, including concentration and duration.

CONCLUSIONS

The results demonstrated the better redifferentiation effect of DCs with the combinational use of transgenic TGF-β3 and a microcavitary alginate hydrogel and implied that DCs would be alternative seed cells for cartilage tissue engineering due to their easily achieved sufficient cell amounts through multiple passages and great potential to redifferentiate to produce cartilaginous extracellular matrix.

Exploring the relationship between pollen viability and inclusion in Paeonia lactiflora after cryopreservation

Pollen, as the male gametophyte, carries half of plant genetic information and is an important source of germplasm. The cryopreservation of pollen can not only preserve germplasm, but also solve the problem of time and space barrier in crossbreeding. So it is of great significance to explore the mechanism of pollen viability maintenance after cryopreservation. In this paper, 10 cultivars of Paeonia lactiflora with different fresh pollen viability that did not change after cryopreservation were taken as objects and the effects of pollen inclusions such as soluble sugar, starch, soluble protein, free amino acids, and proline were explored. The results showed that: (1) The contents of pollen inclusions in the fresh pollen of 10 cultivars were different. After cryopreservation, the contents of starch and free amino acids significantly decreased in 10 cultivars, and the soluble sugar, soluble protein, and proline varied with cultivars. (2) Correlation analysis showed that fresh pollen viability was significantly positively correlated with the soluble sugar (R-values of 0.630) and starch content (R-values of 0.694) in fresh pollen. But after cryopreservation pollen viability was only significantly positively correlated with the starch content (R-values of 0.725). These results suggest that the effects of pollen inclusions on pollen vitality are different before and after cryopreservation. The fresh pollen with higher soluble sugar and starch is more vital. But after cryopreservation, the pollen with high starch content has higher viability. The maintenance of stable pollen viability after cryopreservation appears to be related to starch content or starch metabolism, which requires further to study for a final determination.

Delayed hearing loss after cochlear implantation: Re-evaluating the role of hair cell degeneration

Delayed loss of residual acoustic hearing after cochlear implantation is a common but poorly understood phenomenon due to the scarcity of relevant temporal bone tissues. Prior histopathological analysis of one case of post-implantation hearing loss suggested there were no interaural differences in hair cell or neural degeneration to explain the profound loss of low-frequency hearing on the implanted side (Quesnel et al., 2016) and attributed the threshold elevation to neo-ossification and fibrosis around the implant. Here we re-evaluated the histopathology in this case, applying immunostaining and improved microscopic techniques for differentiating surviving hair cells from supporting cells. The new analysis revealed dramatic interaural differences, with a > 80 % loss of inner hair cells in the cochlear apex on the implanted side, which can account for the post-implantation loss of residual hearing. Apical degeneration of the stria further contributed to threshold elevation on the implanted side. In contrast, spiral ganglion cell survival was reduced in the region of the electrode on the implanted side, but apical counts in the two ears were similar to that seen in age-matched unimplanted control ears. Almost none of the surviving auditory neurons retained peripheral axons throughout the basal half of the cochlea. Relevance to cochlear implant performance is discussed.

Computer-aided exploration of multiobjective optimal temperature profiles in slow freezing for human induced pluripotent stem cells

Human induced pluripotent stem (hiPS) cells have demonstrated promising potential in regenerative medical therapeutics. After successful clinical trials, the demand for hiPS cells has steadily increased. Therefore, the optimization of hiPS cell freezing processes for storage and transportation is essential. Here, we presented a computer-aided exploration of multiobjective optimal temperature profiles in slow freezing for hiPS cells. This study was based on a model that calculates cell survival rates after thawing, and the model was extended to evaluate cell potentials until 24 h after seeding. To estimate parameter values for this extension, freezing experiments were performed using constant cooling rates. Using quality and productivity indicators, we evaluated 16,206 temperature profiles using our model, and a promising profile was obtained. Finally, an experimental investigation of the profile was undertaken, and the contribution of the temperature profile to both quality and productivity was confirmed.

Electroacoustic Responsive Cochlea-on-a-Chip

Organ-on-chips can highly simulate the complex physiological functions of organs, exhibiting broad application prospects in developmental research, disease simulation, as well as new drug research and development. However, there is still less concern about effectively constructing cochlea-on-chips. Here, a novel cochlear organoids-integrated conductive hydrogel biohybrid system with cochlear implant electroacoustic stimulation (EAS) for cochlea-on-a-chip construction and high-throughput drug screening, is presented. Benefiting from the superior biocompatibility and electrical property of conductive hydrogel, together with cochlear implant EAS, the inner ear progenitor cells can proliferate and spontaneously shape into spheres, finally forming cochlear organoids with good cell viability and structurally mature hair cells. By incorporating these progenitor cells-encapsulated hydrogels into a microfluidic-based cochlea-on-a-chip with culture chambers and a concentration gradient generator, a dynamic and high-throughput evaluation of inner ear disease-related drugs is demonstrated. These results indicate that the proposed cochlea-on-a-chip platform has great application potential in organoid cultivation and deafness drug evaluation.

Effect of Oxygen-Glucose Deprivation of Microglia-Derived Exosomes on Hippocampal Neurons: A Study on miR-124 and Inflammatory Cytokines

Stroke is a cerebrovascular disease that threatens human health. Developing safe and effective drugs and finding therapeutic targets has become an urgent scientific problem. The aim of this study was to investigate the effect of oxygen-glucose deprivation of the microglia-derived exosome on hippocampal neurons and its relationship to miR-124 in the exosome. We incubated hippocampal neurons with exosomes secreted by oxygen-glucose deprivation/ reoxygenation (OGD/R) microglia. The levels of glutamic acid (GLU) and gamma-aminobutyric acid (GABA) in the culture supernatant were detected by ELISA. CCK-8 was used to measure neuronal survival rates. The mRNA levels of TNF-α and IL-6 were detected by RT-qPCR to evaluate the effect of exosomes on neurons. RT-qPCR was then used to detect miR-124 in microglia and their secreted exosomes. Finally, potential targets of miR-124 were analyzed through database retrieval, gene detection with dual luciferase reporters, and western blotting experiments. The results showed that the contents of GLU, TNF-α and IL-6 mRNA increased in the supernatant of cultured hippocampal neurons, the content of GABA decreased, and the survival rate of neurons decreased. Oxygen-glucose deprivation increases miR-124 levels in microglia and their released exosomes. miR-124 acts as a target gene on cytokine signaling suppressor molecule 1(SOCS1), while miR-124 inhibitors reduce the expression of TNF-α and IL-6 mRNA in neurons. These results suggest that oxygen- and glucose-deprived microglia regulate inflammatory cytokines leading to reduced neuronal survival, which may be achieved by miR-124 using SOCS1 as a potential target.

Lymphocyte antigen 96: A new potential biomarker and immune target in Parkinson's disease

BACKGROUND

Lymphocyte antigen 96 (LY96) plays an important role in innate immunity and has been reported to be associated with various neurological diseases. However, its role in Parkinson's disease (PD) remains unclear.

METHODS

Transcriptome data from a total of 49 patients with PD and 34 healthy controls were downloaded from the Gene Expression Omnibus (GEO) database to analyse the expression pattern of LY96 and its relationship with gene function and immune-related markers. In addition, peripheral blood samples were collected from clinical patients to validate LY96 mRNA expression levels. Finally, an in vitro cell model of PD based on highly differentiated SH-SY5Y cells was constructed, with small interfering RNA-silenced LY96 expression, and LY96 mRNA level, cell viability, flow cytometry, and mitochondrial membrane potential assays were performed.

RESULTS

The results of the analyses of the GEO database and clinical samples revealed significantly abnormally high LY96 expression in patients with PD compared with healthy controls. The results of cell experiments showed that inhibiting LY96 expression alleviated adverse cellular effects by increasing cell viability, reducing apoptosis, and reducing oxidative stress. Gene set enrichment analysis showed that LY96 was positively correlated with T1 helper cells, T2 helper cells, neutrophils, natural killer T cells, myeloid-derived suppressor cells, macrophages, and activated CD4 cells, and may participate in PD through natural killer cell-mediated cytotoxicity pathways and extracellular matrix receptor interaction pathways.

CONCLUSION

These findings suggested that LY96 might be a novel potential biomarker for PD, and offer insights into its immunoregulatory role.

Survival of transfused red blood cells from a donor with alpha-thalassemia trait in a recipient with sickle cell disease

BACKGROUND

Post-transfusion survival of donor red blood cells (RBCs) is important for effective chronic transfusion therapy in conditions including sickle cell disease (SCD). Biotin labeling RBCs allows direct in vivo measurement of multiple donor RBC units simultaneously post-transfusion.

STUDY DESIGN AND METHODS

In an observational trial of patients with SCD receiving monthly chronic transfusion therapy, aliquots of RBCs from one transfusion episode were biotin-labeled and infused along with the unlabeled RBC units. Serial blood samples were obtained to measure RBC survival. Donor units were tested for RBC indices, hemoglobin fractionation, and glucose-6-phosphate dehydrogenase (G6PD) enzyme activity. For microcytic donor RBCs (MCV < 70 fL), HBA1 and HBA2 genetic testing was performed on whole blood.

RESULTS

We present one recipient, a pediatric patient with SCD and splenectomy who received two RBC units with aliquots from each unit labeled at distinct biotin densities (2 and 18 μg/mL biotin). One donor unit was identified to have microcytosis (MCV 68.5 fL after biotinylation); whole blood sample obtained at a subsequent donation showed 2-gene deletion alpha-thalassemia trait (ɑ-3.7kb/ɑ-3.7kb) and normal serum ferritin. G6PD activity was >60% of normal mean for both. The RBCs with alpha-thalassemia RBC had accelerated clearance and increased surface phosphatidylserine post-transfusion, as compared with the normocytic RBC (half life 65 vs. 86 days, respectively).

DISCUSSION

Post-transfusion RBC survival may be lower for units from donors with alpha-thalassemia trait, although the impact of thalassemia trait donors on transfusion efficacy requires further study.

Cytotoxic and viricidal effects of human semen on mumps virus-infected lymphocytes: In vitro studies

Viruses in human semen may be sexually transmitted via free and cell-mediated viral infection. The potential effects of semen on the infection and sexual transmission of most viruses in semen remain largely unclear. The present study elucidated the inhibitory effects of human seminal plasma (SP) on Jurkat cell (JC)-mediated mumps virus (MuV) infection. We demonstrated that MuV efficiently infected JCs and that the JCs infected by MuV (JC-MuV) mediated MuV infection of HeLa cells. Remarkably, SP was highly cytotoxic to JCs and inhibited JC-MuV infection of HeLa cells. The cytotoxic factor possessed a molecular weight of less than 3 kDa, whereas that of the viricidal factor was over 100 kDa. The cooperation of cytotoxic and viricidal factors was required for the SP inhibition of JC-MuV infection, and prostatic fluid (PF) was responsible for both the cytotoxic and viricidal effects of SP. The cytotoxic effects we observed were resistant to the treatment of PF with boiling water, proteinase K, RNase A, and DNase I. Our results provide novel insights into the antiviral properties of SP, which may limit cell-mediated sexual viral transmission.

The glutathione S-transferase Gstt1 drives survival and dissemination in metastases

Identifying the adaptive mechanisms of metastatic cancer cells remains an elusive question in the treatment of metastatic disease, particularly in pancreatic cancer (pancreatic adenocarcinoma, PDA). A loss-of-function shRNA targeted screen in metastatic-derived cells identified Gstt1, a member of the glutathione S-transferase superfamily, as uniquely required for dissemination and metastasis, but dispensable for primary tumour growth. Gstt1 is expressed in latent disseminated tumour cells (DTCs), is retained within a subpopulation of slow-cycling cells within existing metastases, and its inhibition leads to complete regression of macrometastatic tumours. This distinct Gstt1high population is highly metastatic and retains slow-cycling phenotypes, epithelial-mesenchymal transition features and DTC characteristics compared to the Gstt1low population. Mechanistic studies indicate that in this subset of cancer cells, Gstt1 maintains metastases by binding and glutathione-modifying intracellular fibronectin, in turn promoting its secretion and deposition into the metastatic microenvironment. We identified Gstt1 as a mediator of metastasis, highlighting the importance of heterogeneity and its influence on the metastatic tumour microenvironment.

Live-cell imaging powered by computation

The proliferation of microscopy methods for live-cell imaging offers many new possibilities for users but can also be challenging to navigate. The prevailing challenge in live-cell fluorescence microscopy is capturing intra-cellular dynamics while preserving cell viability. Computational methods can help to address this challenge and are now shifting the boundaries of what is possible to capture in living systems. In this Review, we discuss these computational methods focusing on artificial intelligence-based approaches that can be layered on top of commonly used existing microscopies as well as hybrid methods that integrate computation and microscope hardware. We specifically discuss how computational approaches can improve the signal-to-noise ratio, spatial resolution, temporal resolution and multi-colour capacity of live-cell imaging.

Ex vivo culture resting time impacts transplantation outcomes of genome-edited human hematopoietic stem and progenitor cells in xenograft mouse models

Ex vivo resting culture is a standard procedure following genome editing in hematopoietic stem and progenitor cells (HSPCs). However, prolonged culture may critically affect cell viability and stem cell function. We investigated whether varying durations of culture resting times impact the engraftment efficiency of human CD34+ HSPCs edited at the BCL11A enhancer, a key regulator in the expression of fetal hemoglobin. We employed electroporation to introduce CRISPR-Cas9 components for BCL11A enhancer editing and compared outcomes with nonelectroporated (NEP) and electroporated-only (EP) control groups. Post-electroporation, we monitored cell viability, death rates, and the frequency of enriched hematopoietic stem cell (HSC) fractions (CD34+CD90+CD45RA- cells) over a 48-hour period. Our findings reveal that while the NEP group showed an increase in cell numbers 24 hours post-electroporation, both EP and BCL11A-edited groups experienced significant cell loss. Although CD34+ cell frequency remained high in all groups for up to 48 hours post-electroporation, the frequency of the HSC-enriched fraction was significantly lower in the EP and edited groups compared to the NEP group. In NBSGW xenograft mouse models, both conditioned with busulfan and nonconditioned, we found that immediate transplantation post-electroporation led to enhanced engraftment without compromising editing efficiency. Human glycophorin A+ (GPA+) red blood cells (RBCs) sorted from bone marrow of all BCL11A edited mice exhibited similar levels of γ-globin expression, regardless of infusion time. Our findings underscore the critical importance of optimizing the culture duration between genome editing and transplantation. Minimizing this interval may significantly enhance engraftment success and minimize cell loss without compromising editing efficiency. These insights offer a pathway to improve the success rates of genome editing in HSPCs, particularly for conditions like sickle cell disease.

Mechanical complexity of living cells can be mapped onto simple homogeneous equivalents

Biological cells are built up from different constituents of varying size and stiffness which all contribute to the cell's mechanical properties. Despite this heterogeneity, in the analysis of experimental measurements one often assumes a strongly simplified homogeneous cell and thus a single elastic modulus is assigned to the entire cell. This ad-hoc simplification has so far mostly been used without proper justification. Here, we use computer simulations to show that indeed a mechanically heterogeneous cell can effectively be replaced by a homogeneous equivalent cell with a volume averaged elastic modulus. To demonstrate the validity of this approach, we investigate a hyperelastic cell with a heterogeneous interior under compression and in shear/channel flow mimicking atomic force and microfluidic measurements, respectively. We find that the homogeneous equivalent cell reproduces quantitatively the behavior of its heterogeneous counterpart, and that this equality is largely independent of the stiffness or spatial distribution of the heterogeneity.

Extracellular vesicles from non-neuroendocrine SCLC cells promote adhesion and survival of neuroendocrine SCLC cells

Small cell lung cancer (SCLC) tumors are made up of distinct cell subpopulations, including neuroendocrine (NE) and non-neuroendocrine (non-NE) cells. While secreted factors from non-NE SCLC cells have been shown to support the growth of the NE cells, the underlying molecular factors are not well understood. Here, we show that exosome-type small extracellular vesicles (SEVs) secreted from non-NE SCLC cells promote adhesion and survival of NE SCLC cells. Proteomic analysis of purified SEVs revealed that extracellular matrix (ECM) proteins and integrins are highly enriched in SEVs of non-NE cells whereas nucleic acid-binding proteins are enriched in SEVs purified from NE cells. Addition of select purified ECM proteins identified in purified extracellular vesicles (EVs), specifically fibronectin, laminin 411, and laminin 511, were able to substitute for the role of non-NE-derived SEVs in promoting adhesion and survival of NE SCLC cells. Those same proteins were differentially expressed by human SCLC subtypes. These data suggest that ECM-carrying SEVs secreted by non-NE cells play a key role in supporting the growth and survival of NE SCLC cells.

Mesenchymal stromal cell response to intervertebral disc-like pH is tissue source dependent

Intervertebral disc (IVD) degeneration (IVDD) has become increasingly prevalent and is a common contributing factor to low back pain. Current treatment options are limited to either symptom management or surgery. A promising treatment option being explored is intradiscal administration of mesenchymal stromal cells (MSCs). However, there remains a gap in knowledge as to whether MSCs from different tissue sources have similar responses to the low pH microenvironment of the IVD and the possible mechanisms governing these responses. To study this, MSCs from three different tissue sources: adipose (adipose-derived mesenchymal stem cell), bone marrow (bone marrow mesenchymal stem cells), and amnion (amniotic membrane mesenchymal stem cell) were cultured at low pHs representative of IVDD. MSCs were assessed for survival, senescence, apoptosis, metabolic activity, and cytokine release profile. Additionally, western blot was utilized to assess acid sensing ion channel 1 and 3 expression. The results of this study indicated that MSC viability, cell proliferation, senescence, and metabolic activity is negatively affected by low pH and alters MSC cytokine production. This study also demonstrated that MSCs behavior is dependent on tissue source. Understanding how MSC behavior is altered by pH will allow further research aimed at increasing the efficacy of MSC therapy to promote in situ IVD tissue regeneration to combat IVDD.

Comprehensive characterisation and cryopreservation optimisation of buffalo (Bubalus bubalis) adipose tissue-derived mesenchymal stem cells

Over half of the world's buffalo (Bubalus bubalis) inhabit India, and buffaloes frequently encounter health challenges that resist conventional treatments, prompting the exploration of alternative therapeutic strategies. One promising approach is stem cell therapy, particularly multipotent mesenchymal/stromal stem cells (MSCs). These cells have shown significant efficacy in addressing various diseases in livestock that exhibit resistance to conventional therapies. Adipose tissue-derived MSCs (ADSCs) have garnered attention due to their accessibility and robust expansion potential. The current study comprehensively characterises buffalo ADSCs (bADSCs), confirming their identity as MSCs capable of differentiating into diverse cell lineages-the identified characteristics position bADSCs as promising candidates for applications in regenerative medicine, applicable in veterinary contexts. Notably, the study established that a cryoprotective solution comprising 10 % dimethyl sulfoxide and 90 % fetal bovine serum is optimal for preserving bADSCs. This cryoprotective solution maintains vital parameters, including viability, apoptosis, senescence, cell adherence, adherent cell viability, metabolic and clonogenic efficiency, and the activity of reactive oxygen species and trilineage differentiation potential following thawing. These findings lay the foundation for developing a cryo-banking system for bADSCs. Subsequent research efforts are focused on exploring the therapeutic potential of bADSCs in specific disease models and clinical settings. The outcomes of such investigations may pave the way for innovative and effective treatments, further enhancing our understanding of the regenerative capabilities of bADSCs.

Theory-based cryopreservation mode of mesenchymal stromal cell spheroids

Cryopreservation of spheroids requires development of new improved methods. The plasma membranes permeability coefficients for water and cryoprotectants determine time characteristics of mass transfer through the cell membranes, and therefore the optimal modes of cells cryopreservation. Here we proposed an approach to cryopreservation of multicellular spheroids which considers their generalized characteristics as analogues of the membranes' permeability coefficients of the individual cells. We have determined such integral characteristics of spheroids from mesenchymal stromal cells (MSCs) as osmotically inactive volume; permeability coefficients for water and Me2SO molecules and the activation energy of their penetration. Based on these characteristics, we calculated the osmotic behavior of multicellular spheroids under cooling conditions to select the optimal cooling rate. We also determined the optimal cooling rate of spheroids using the probabilistic model developed based on the two-factor theory of cryodamage. From the calculation it follows that the optimal cooling rate of the MSC-based spheroids is 0.75°С/min. To verify the obtained theoretical estimates, we conducted experiments on freezing MSC-based spheroids under different modes. The obtained results of primary viability screening indicate that freezing at a constant linear cooling rate of 0.75-1.0°С/min gives a good result. Theoretical prediction of the spheroid osmotic behavior during cooling provided the basis for experimental verification of varying the temperature to which slow cooling should be carried out before immersion in liquid nitrogen. Slow freezing of spheroids to -40 °C followed by immersion in liquid nitrogen was shown to preserve cells better than slow freezing to -80 °C. Obtained data allow more effective use of MSC-based spheroids in drug screening and regenerative medicine.