Dimethyl sulfoxide (DMSO) produces widespread apoptosis in the developing central nervous system

Neuronal effect of 0.3 % DMSO and the synergism between 0.3 % DMSO and loss function of UCH-L1 on Drosophila melanogaster model

Dimethyl sulfoxide (DMSO) is a polar aprotic solvent which is widely used in biological and medical studies and as a vehicle for pharmacological therapy. DMSO from 0.1 % to 0.5 %, particularly 0.3 % is commonly used as solvent to dissolve compounds when testing their effect on living cell, tissues including nerve cell. However, scientific data on the effects of DMSO on nervous system is limited. Here, we present our data of case study on investigation the effects of DMSO at 0.3 % concentration on nerve cell of Drosophila melanogaster model. We found that 0.3 % DMSO concentration had affected on the active zone and glutamate receptor. Notably, this study also revealed the synergistic effect of 0.3 % DMSO and loss function of dUCH (the homolog of Ubiquitin Carboxyl terminal Hydrolase -L1, UCH-L1 in D. melanogaster). This combination caused more serious abnormalities in synapse structure, particularly number of boutons on Neuromuscular Junction, NMJ. Furthermore, 0.3 % DMSO reduced the amount of ubiquitinylated protein aggregates in the indirect flight muscle of both normal and genectic defect fly model. Taken together, data in this sytudy indicated that 0.3 % DMSO caused the aberrant morphology of the synaptic structure and decreased the number of ubiquitinylated proteins in the indirect flight muscle of Drosophila. The data from the study contributed new evidence of the effects of DMSO on the nervous system. Signigicantly, this study revealed that DMSO affected on neuron cell at low concentration which widely used as pharmacological solvent.

Cryopreservation practices in clinical and preclinical iPSC-based cell therapies: Current challenges and future directions

Induced pluripotent stem cells (iPSCs) offer significant therapeutic potential, but cryopreservation challenges, particularly the reliance on cytotoxic Dimethyl Sulfoxide (Me2SO), hinder their clinical application. This review examines current cryopreservation practices in clinical and preclinical iPSC-based therapies, highlighting the consistent use of Me2SO and the logistical challenges of post-thaw processing. The findings underscore the urgent need for alternative cryopreservation techniques to ensure the safety and efficacy of off-the-shelf iPSC therapies.

CEST effect of dimethyl sulfoxide at negative offset frequency

Dimethyl sulfoxide (DMSO) has wide biomedical applications such as cryoprotectant and hydrophobic drug carrier. Here, we report for the first time that DMSO can generate a distinctive chemical exchange saturation transfer (CEST) signal at around -2 ppm. Structural analogs of DMSO, including aprotic and protic solvents, also demonstrated CEST signals from -1.4 to -3.8 ppm. When CEST detectable barbituric acid (BA) was dissolved in DMSO solution and was co-loaded to liposome, two obvious peaks at 5 and -2 ppm were observed, indicating that DMSO and related solvent system can be monitored in a label-free manner via CEST, which can be further applied to imaging drug nanocarriers. With reference to previous studies, there could be molecular interactions or magnetization transfer pathways, such as the relayed nuclear Overhauser enhancement (rNOE), that lead to this detectable CEST contrast at negative offset frequencies of the Z-spectrum. Our findings suggest that small molecules of organic solvents could be involved in magnetization transfer processes with water and readily detected by CEST magnetic resonance imaging (MRI), providing a new avenue for detecting solvent-water and solvent-drug interactions.

The Inhibition of Interfacial Ice Formation and Stress Accumulation with Zwitterionic Betaine and Trehalose for High-Efficiency Skin Cryopreservation

Cryopreservation is a promising technique for the long-term storage of skin. However, the formation of ice crystals during cryopreservation unavoidably damages skin structure and functionality. Currently, the lack of thorough and systematic investigation into the internal mechanisms of skin cryoinjury obstructs the advancement of cryopreservation technology. In this study, we identified 3 primary contributors to skin cryoinjury: interfacial ice nucleation, stress accumulation, and thermal stress escalation. We emphasized the paramount role of interfacial ice nucleation in provoking ice growth within the skin during the cooling process. This progress subsequently leads to stress accumulation within the skin. During the rewarming process, the brittleness of skin, previously subjected to freezing, experienced a marked increase in thermal stress due to ice recrystallization. Based on these insights, we developed a novel zwitterionic betaine-based solution formulation designed for cryopreservation skin. This cryoprotective agent formulation exhibited superior capability in lowering ice nucleation temperatures and inhibiting ice formation at interfaces, while also facilitating the growth of smooth and rounded ice crystals compared to sharp-edged and cornered crystals formed in aqueous solutions. As a result, we successfully achieved prolonged cryopreservation of the skin for at least 6 months, while preserving 98.7% of structural integrity and 94.7% of Young's modulus. This work provides valuable insights into the mechanisms of ice crystal damage during organ cryopreservation and profoundly impacts the field of organ transplantation and regenerative medicine.

Optimizing cryopreservation strategies for scalable cell therapies: A comprehensive review with insights from iPSC-derived therapies

Off-the-shelf cell therapies hold significant curative potential for conditions, such as Parkinson's disease and heart failure. However, these therapies face unique cryopreservation challenges, especially when novel routes of administration, such as intracerebral or epicardial injection, require cryopreservation media that are safe for direct post-thaw administration. Current practices often involve post-thaw washing to remove dimethyl sulfoxide (Me2SO), a cytotoxic cryoprotective agent, which complicates the development and clinical translation of off-the-shelf therapies. To overcome these obstacles, there is a critical need to explore Me2SO-free cryopreservation methods. While such methods typically yield suboptimal post-thaw viability with conventional slow-freeze protocols, optimizing freezing profiles offers a promising strategy to enhance their performance. This comprehensive review examines the latest advancements in cryopreservation techniques across various cell therapy platforms, with a specific case study of iPSC-derived therapies used to illustrate the scalability challenges. By identifying key thermodynamic and biochemical phenomena that occur during freezing, this review aims to identify cell-type independent approaches to improve the efficiency and efficacy of cryopreservation strategies, thereby supporting the widespread adoption and clinical success of off-the-shelf cell therapies.

Permeability and Toxicity of Cryoprotective Agents in Silkworm Embryos: Impact on Cryopreservation

The permeation of cryoprotectants into insect embryos is critical for successful cryopreservation. However, the permeability of silkworm embryos to cryoprotectants and the effects of cryopreservation remain poorly studied. In this study, we evaluated the permeability and toxicity of four cryoprotective agents (CPAs) as well as the vitrification effect on the viability of silkworm embryos. Among the four CPAs, propylene glycol (PG) showed the best permeability. Ethylene glycol (EG) and PG were the least toxic CPAs, but glycerol (GLY) and dimethyl sulfoxide (DMSO) were more toxic. Moreover, we examined several factors including the kind and the concentration of CPAs, exposure time, embryonic stage, and silkworm strains. Embryos at the earlier phases of stage 25 were more tolerant to vitrification using EG. We found that over 21% of embryos treated with EG at the early 2 phase of stage 25: 163 h after egg laying (AEL) developed and progressed to serosa ingestion after vitrification and rewarming. The result was the same in other strains as well. Our results are valuable for the development of new cryopreservation protocols of silkworm embryos.

Dataset of cell viability and analytes released by cancer cell lines exposed to low pH and conditioned medium

Cancer cells influence their microenvironment by secreting factors that promote tumour growth and survival while evading immune-mediated destruction. We previously determined the expression of secreted factors in breast and oesophageal squamous cell carcinoma cell lines (MCF-7 and WHCO6, respectively) using Luminex assays. These cells were subsequently treated with low pH medium to mimic in vivo acid exposure, and the effects on cell viability, proliferation, and secretion of cytokines, chemokines and growth factors were described [1]. Here, we present the datasets from these experiments in addition to data obtained from treating cell lines with conditioned medium from apoptotic cell cultures.

Systematic cryopreservation study of cardiac myoblasts in suspension

H9c2 myoblasts are a cell line derived from embryonic rat heart tissue and demonstrate the ability to differentiate to cardiac myotubes upon reduction of the serum concentration (from 10% to 1%) and addition of all-trans retinoic acid in the growth medium. H9c2 cells are increasingly being used as an easy-to-culture proxy for some functions of cardiomyocytes. The cryobiology of cardiac cells including H9c2 myoblasts has not been studied as extensively as that of some cell types. Consequently, it is important to characterize the cryobiological response and systematically develop well-optimized cryopreservation protocols for H9c2 cells to have optimal and consistent viability and functionality after thaw for high quality studies with this cell type. In this work, an interrupted slow cooling protocol (graded freezing) was applied to characterize H9c2 response throughout the cooling profile. Important factors that affect the cell response were examined, and final protocols that provided the highest post-thaw viability are reported. One protocol uses the common cryoprotectant dimethyl sulfoxide combined with hydroxyethyl starch, which will be suitable for applications in which the presence of dimethyl sulfoxide is not an issue; and the other protocol uses glycerol as a substitute when there is a desire to avoid dimethyl sulfoxide. Both protocols achieved comparable post-thaw viabilities (higher than 80%) based on SYTO 13/GelRed flow cytometry results. H9c2 cells cryopreserved by either protocol showed ability to differentiate to cardiac myotubes comparable to fresh (unfrozen) H9c2 cells, and their differentiation to cardiac myotubes was confirmed with i) change in cell morphology, ii) expression of cardiac marker troponin I, and iii) increase in mitochondrial mass.

Dimethyl Sulfoxide-Free Cryopreservation of Differentiated Human Neuronal Cells

In recent years, cells provided by cell banks and medical facilities have been used for cell therapy, regenerative therapy, and fundamental research. Cryopreservation is an effective means of maintaining stable cell quality over a long period of time. The slow freezing method is most suitable for processing many human cells isolated simultaneously from organs and tissues, but it is necessary to develop a freezing solution for this method. In this study, we report the successful development of a dimethyl sulfoxide (DMSO)-free freezing medium for differentiated neuronal cells. Neuronal differentiation results in the differentiation of undifferentiated SK-N-SH cells into neuronal cells. A basic freezing medium (BFM) was prepared using Dulbecco's modified Eagle's medium, 1 M maltose, and 1% sericin as the essential ingredients, supplemented with 5%-40% propylene glycol (PG). Each BFM supplemented with 5%-40% PG was evaluated in undifferentiated cells. After thawing, BFM supplemented with 10% and 20% PG were 83% and 88% viable, respectively. There was no significant difference between the 10% and 20% PG groups. However, a significant difference was observed when the concentration of PG in the BFM decreased by 5% (5% PG vs. 10% PG; p = 0.0026). Each DMSO-free BFM was evaluated using differentiated neuronal cells. There was no significant difference between the 10% PG BFM and stem-CB-free groups. Viability was significantly different in the 10% glycerol BFM (4.8%) and 10% PG BFM (45%) (p = 0.028). The differentiated cells with 10% PG BFM showed higher adherence to culture dishes than those with 10% glycerol BFM. These results show that BFM containing PG was effective in differentiating neuronal cells. DMSO affects the central nervous system at low concentrations. This report indicates that DMSO is unsuitable for neuronal cells with multipotent differentiation potential. Therefore, it is essential for cell banking and transplantation medicine services to select appropriate cell freezing media.

Cryopreservation of human cerebral microvascular endothelial cells with glycerol

The cryopreservation of human cerebral microvascular endothelial cells (hCMEC) has facilitated their commercial availability for research studying the blood-brain barrier. The currently employed cryopreservation protocol uses 10% dimethyl sulfoxide (Me2SO) in cell medium, or 5% Me2SO in 95% fetal bovine serum (FBS) as cryoprotective agents (CPAs). However, Me2SO is toxic to cells and FBS is animal-derived and not chemically defined, so reducing the concentrations of these components is desirable. Recently, we showed that cryopreserving hCMEC in cell medium with 5% Me2SO and 6% hydroxyethyl starch (HES) results in over 90% post-thaw cell viability. This previous work was performed using an interrupted slow cooling (graded freezing) approach followed by SYTO13/GelRed staining to assay for membrane integrity. In this paper, we repeated graded freezing of hCMEC in cell medium containing 5% Me2SO and 6% HES, but this time using Calcein AM/propidium iodide staining to ensure that the stain is an equivalent alternative to SYTO13/GelRed for assessment of cell viability, and that results are comparable to those previously published. Next, using graded freezing experiments and Calcein AM/propidium iodide staining, we examined the effectiveness of non-toxic glycerol as a CPA at different concentrations, loading times, and cooling rates. The cryobiological response of hCMEC was used to develop a protocol that optimizes both the permeating and non-permeating capabilities of glycerol. HCMEC in cell medium loaded with 10% glycerol for 1 h at room temperature, ice nucleated at -5 °C and held for 3 min, and then cooled at -1 °C/min to -30 °C before plunging into liquid nitrogen had post-thaw viability of 87.7% ± 1.8%. Matrigel tube formation assay and immunocytochemical staining of junction protein ZO-1 were carried out on post-thaw hCMEC to ensure that the cryopreserved cells were viable and functional, in addition to being membrane-intact.

Preparation of cryopreserved chimeric antigen receptor T cells for the locoreogional delivery to the neural axis

BACKGROUND AIMS

Intracranial (IC) locoregional delivery of chimeric antigen receptor (CAR) T cells presents an attractive delivery method to central nervous system tumors. Although IC delivery is actively being employed in early-phase clinical studies, no thaw/wash methods have been published to remove the neurotoxic cryoprotectant dimethyl sulfoxide (DMSO) from CAR T-cell products before IC administration. Thus, the aim of this study was to develop and validate a simple thaw/wash procedure.

METHODS

We developed a thaw/wash procedure that consist of product thaw at 37°C, equilibration for 5 min in 1 volume of preservative-free normal saline (PFNS), dilution with an additional 8 volumes of PFNS, removal of DMSO through a washing step, resuspension in 2.0 mL of PFNS and storage in a syringe at 20-25°C. Final formulated products (FPs) were assessed for quality and safety attributes and stability over 3 h from the completion of the thaw. Stability parameters included CAR T-cell viability, transgene surface expression and cytolytic activity.

RESULTS

The developed procedure reduced the calculated % of DMSO to less than 0.025%. FP cell viability and recovery (versus pre-cryopreservation) were within acceptable specifications (mean viability: 85.3%, range: 83%-88%; total nucleated cell recovery mean: 76.5%, range: 65.4%-82.5%). Other prespecified quality assurance/quality control parameters including appearance/ integrity, sterility and endotoxin level (≤1.0 EU/mL), were also met by all FPs (n = 3). Three hours' post thaw/wash stability was confirmed. All products maintained cell viability greater than 70% (mean, 80.0%; range, 79%-81%), with no significant change in transgene expression or cytolytic activity of B7-H3-CAR T cells compared with thawed not diluted/washed control CAR T cells.

CONCLUSIONS

We have developed a simple thaw/wash procedure to prepare B7-H3-CAR T cells for their locoregional delivery to the neural axis. While we focus here on CAR T cells, the methods could be readily adapted to other cryopreserved immune effector cell products.

Cisplatin Dependent Secretion of Immunomodulatory High Mobility Group Box 1 (HMGB1) Protein from Lung Cancer Cells

High mobility group box 1 (HMGB1) is secreted from activated immune cells, necrotic cells, and certain cancers. Previous studies have reported that different patterns of post-translational modification, particularly acetylation and oxidation, mediate HMGB1 release and confer distinct extracellular HMGB1 signaling activity. Here we report that cisplatin but not carboplatin induces secretion of HMGB1 from human A549 non-small cell lung cancer (NSCLC) cells. Cisplatin-mediated HMGB1 secretion was dose-dependent and was regulated by nuclear exportin 1 (XPO1) also known as chromosomal maintenance 1 (CRM1) rather than adenosine diphosphate (ADP)-ribosylation, acetylation, or oxidation. HMGB1, as well as lysine acetylation and cysteine disulfide oxidation of secreted HMGB1, were monitored by sensitive and specific assays using immunoprecipitation, stable isotope dilution, differential alkylation, and nano liquid chromatography parallel reaction monitoring/high-resolution mass spectrometry (nano-LC-PRM/HRMS). A major fraction of the HMGB1 secreted by low-dose cisplatin treatment of A549 NSCLC cells was found to be in the fully reduced form. In contrast, mainly oxidized forms of HMGB1 were secreted by dimethyl sulfoxide (DMSO)-mediated apoptosis. These findings suggest that inhibition of XPO1 could potentiate the anti-tumor activity of cisplatin by increasing the nuclear accumulation of HMGB1 protein, an inhibitor of cisplatin DNA-adduct repair. Furthermore, low-dose cisplatin therapy could modulate the immune response in NSCLC through the established chemokine activity of extracellular reduced HMGB1. This could potentially enhance the efficacy of subsequent immunotherapy treatment.

Synergetic effect of β-asarone and cannabidiol against Aβ aggregation in vitro and in vivo

Alzheimer's disease (AD) is a complex and multifactorial neurodegenerative disorder, and it is unlikely that any single drug or intervention will be very successful. The pathophysiology of Alzheimer's disease involves a range of complicated biological processes, including the accumulation of beta-amyloid protein and tau protein. Given the complexity of AD and amyloid accumulation, a combination of interventions remains to be further explored. Here, we investigated the potential of combining β-asarone and cannabidiol (CBD) as a treatment for AD. The study analyzed the combined effects of these two phytochemicals on beta-amyloid (Aβ) protein aggregation and toxicity in bulk solution, in cells as well as in C.elegans. We detailed the morphological and size changes of Aβ40 aggregates in the presence of β-asarone and cannabidiol. More importantly, the presence of both compounds synergistically inhibited apoptosis and downregulated relative gene expression in cells, and that it may also slow aging, decrease the rate of paralysis, enhance learning capacity, and boost autophagy activity in C.elegans. Our studies suggest that multiple drugs, like β-asarone and CBD, may be potentially developed as a medicinal adjunct in the treatment of AD, although further clinical trials are needed to determine the efficacy and safety of this combination treatment in humans.

Impact of cryopreservation on viability, gene expression and function of enteric nervous system derived neurospheres

Introduction: Impairment of both the central and peripheral nervous system is a major cause of mortality and disability. It varies from an affection of the brain to various types of enteric dysganglionosis. Congenital enteric dysganglionosis is characterized by the local absence of intrinsic innervation due to deficits in either migration, proliferation or differentiation of neural stem cells. Despite surgery, children's quality of life is reduced. Neural stem cell transplantation seems a promising therapeutic approach, requiring huge amounts of cells and multiple approaches to fully colonize the diseased areas completely. A combination of successful expansion and storage of neural stem cells is needed until a sufficient amount of cells is generated. This must be combined with suitable cell transplantation strategies, that cover all the area affected. Cryopreservation provides the possibility to store cells for long time, unfortunately with side effects, i.e., upon vitality. Methods: In this study we investigate the impact of different freezing and thawing protocols (M1-M4) upon enteric neural stem cell survival, protein and gene expression, and cell function. Results: Freezing enteric nervous system derived neurospheres (ENSdN) following slow-freezing protocols (M1-3) resulted in higher survival rates than flash-freezing (M4). RNA expression profiles were least affected by freezing protocols M1/2, whereas the protein expression of ENSdN remained unchanged after treatment with protocol M1 only. Cells treated with the most promising freezing protocol (M1, slow freezing in fetal calf serum plus 10% DMSO) were subsequently investigated using single-cell calcium imaging. Freezing of ENSdN did not alter the increase in intracellular calcium in response to a specific set of stimuli. Single cells could be assigned to functional subgroups according to response patterns and a significant shift towards cells responding to nicotine was observed after freezing. Discussion: The results demonstrate that cryopreservation of ENSdN is possible with reduced viability, only slight changes in protein/gene expression patterns and without an impact on the neuronal function of different enteric nervous system cell subtypes, with the exception of a subtle upregulation of cells expressing nicotinergic acetylcholine receptors. In summary, cryopreservation presents a good method to store sufficient amounts of enteric neural stem cells without neuronal impairment, in order to enable subsequent transplantation of cells into compromised tissues.

Modulation of the endoplasmic reticulum stress and unfolded protein response mitigates the behavioral effects of early-life stress

BACKGROUND

Early-life stress (ELS) affects brain development and increases the risk of mental disorders associated with the dysfunction of the medial prefrontal cortex (mPFC). The mechanisms of ELS action are not well understood. Endoplasmic reticulum (ER) stress and the unfolded protein response (UPR) are cellular processes involved in brain maturation through the regulation of pro-survival or proapoptotic processes. We hypothesized that ER stress and the UPR in the mPFC are involved in the neurobiology of ELS.

METHODS

We performed a maternal separation (MS) procedure from postnatal days 1 to 14 in rats. Before each MS, pups were injected with an inhibitor of ER stress, salubrinal or a vehicle. The mRNA and protein expression of UPR and apoptotic markers were evaluated in the mPFC using RT-qPCR and Western blot methods, respectively. We also estimated the numbers of neurons and glial cells using stereological methods. Additionally, we assessed behavioral phenotypes related to fear, anhedonia and response to psychostimulants.

RESULTS

MS slightly enhanced the activation of the UPR in juveniles and modulated the expression of apoptotic markers in juveniles and preadolescents but not in adults. Additionally, MS did not affect the numbers of neurons and glial cells at any age. Both salubrinal and vehicle blunted the expression of UPR markers in juvenile and preadolescent MS rats, often in a treatment-specific manner. Moreover, salubrinal and vehicle generally alleviated the behavioral effects of MS in preadolescent and adult rats.

CONCLUSIONS

Modulation of ER stress and UPR processes may potentially underlie susceptibility or resilience to ELS.

Cryoprotection in Human Mesenchymal Stromal/Stem Cells: Synergistic Impact of Urea and Glucose

Standard freezing protocols of clinically relevant cell lines commonly employ agents such as fetal bovine serum and dimethyl sulfoxide, which are a potential concern from both a regulatory and a patient safety perspective. The aim of this work was to develop formulations with safe and well tolerated excipients for the (cryo-) preservation of cell therapy products. We evaluated the cryoprotective capabilities of urea and glucose through measurements of cell metabolic activity. Freezing of clinically relevant human mesenchymal stromal/stem cells and human dermal fibroblasts at ≤ - 65°C at equimolar ratios of urea and glucose resulted in comparable viabilities to established dimethyl sulfoxide. Pre-incubation of human mesenchymal stromal/stem cells in trehalose and addition of mannitol and sucrose to the formulation further enhanced cell viability after freeze-thaw stress. Other cell types assessed (A549 and SK-N-AS) could not satisfactorily be preserved with urea and glucose, highlighting the need for tailored formulations to sustain acceptable cryopreservation.

The effect of acute acid exposure on immunomodulatory protein secretion, cell survival, and cell cycle progression in tumour cell lines

Cancer develops when multiple systems fail to suppress uncontrolled cell proliferation. Breast cancers and oesophageal squamous cell carcinoma (OSCC) are common cancers prone to genetic instability. They typically occur in acidic microenvironments which impacts on cell proliferation, apoptosis, and their influence on surrounding cells to support tumour growth and immune evasion. This study aimed to evaluate the impact of the acidic tumour microenvironment on the production of pro-tumorigenic and immunomodulatory factors in cancer cell lines. Multiple factors that may mediate immune evasion were secreted including IL-6, IL-8, G-CSF, IP-10, GDF-15, Lipocalin-2, sICAM-1, and myoglobin. Others, such as VEGF, FGF, and EGF that are essential for tumour cell survival were also detected. Treatment with moderate acidity did not significantly affect secretion of most proteins, whereas very low pH did. Distinct differences in apoptosis were noted between the cell lines, with WHCO6 being better adapted to survive at moderate acid levels. Conditioned medium from acid-treated cells stimulated increased cell viability and proliferation in WHCO6, but increased cell death in MCF-7. This study highlights the importance of acidic tumour microenvironment in controlling apoptosis, cell proliferation, and immune evasion which may be different at different anatomical sites. Immunomodulatory molecules and growth factors provide therapeutic targets to improve the prognosis of individuals with cancer.

Photo-responsive polymeric micelles for the light-triggered release of curcumin targeting antimicrobial activity

Nanocarriers have been successfully used to solubilize, deliver, and increase the bioavailability of curcumin (CUR), but slow CUR release rates hinder its use as a topical photosensitizer in antimicrobial photodynamic therapy. A photo-responsive polymer (PRP) was designed for the light-triggered release of CUR with an effective light activation-dependent antimicrobial response. The characterization of the PRP was compared with non-responsive micelles comprising Pluronics™ P123 and F127. According to the findings, the PRP formed photo-responsive micelles in the nanometric scale (< 100 nm) with a lower critical micelle concentration (3.74 × 10^-4 M^-1, 5.8 × 10^-4 M^-1, and 7.2 × 10^-6 M^-1 for PRP, F127, P123, respectively, at 25°C) and higher entrapment efficiency of CUR (88.7, 77.2, and 72.3% for PRP, F127, and P123 micelles, respectively) than the pluronics evaluated. The PRP provided enhanced protection of CUR compared to P123 micelles, as demonstrated in fluorescence quenching studies. The light-triggered release of CUR from PRP occurred with UV light irradiation (at 355 nm and 25 mW cm^-2) and a cumulative release of 88.34% of CUR within 1 h compared to 80% from pluronics after 36 h. In vitro studies showed that CUR-loaded PRP was non-toxic to mammal cell, showed inactivation of the pathogenic microorganisms Candida albicans, Pseudomonas aeruginosa, and methicillin-resistant Staphylococcus aureus, and decreased biofilm biomass when associated with blue light (455  nm, 33.84 J/cm²). The findings show that the CUR-loaded PRP micelle is a viable option for antimicrobial activity.

Mitochondrial Targeting and Imaging with Small Organic Conjugated Fluorophores: A Review

The last decade has seen an increasingly large number of studies reporting on the development of novel small organic conjugated systems for mitochondrial imaging exploiting optical signal transduction pathways. Mitochondria are known to play a critical role in a number of key biological processes, including cellular metabolism. Importantly, irregularities on their working function are nowadays understood to be intimately linked to a range of clinical conditions, highlighting the importance of targeting mitochondria for therapeutic benefits. In this work we carry out an in-depth evaluation on the progress to date in the field to pave the way for the realization of superior alternatives to those currently existing. The manuscript is structured by commonly used chemical scaffolds and comprehensively covers key aspects factored in design strategies such as synthetic approaches as well as photophysical and biological characterization, to foster collaborative work among organic and physical chemists as well as cell biologists.

Amyloid Disassembly: What Can We Learn from Chaperones?

Protein aggregation and subsequent accumulation of insoluble amyloid fibrils with cross-β structure is an intrinsic characteristic of amyloid diseases, i.e., amyloidoses. Amyloid formation involves a series of on-pathway and off-pathway protein aggregation events, leading to mature insoluble fibrils that eventually accumulate in multiple tissues. In this cascade of events, soluble oligomeric species are formed, which are among the most cytotoxic molecular entities along the amyloid cascade. The direct or indirect action of these amyloid soluble oligomers and amyloid protofibrils and fibrils in several tissues and organs lead to cell death in some cases and organ disfunction in general. There are dozens of different proteins and peptides causing multiple amyloid pathologies, chief among them Alzheimer's, Parkinson's, Huntington's, and several other neurodegenerative diseases. Amyloid fibril disassembly is among the disease-modifying therapeutic strategies being pursued to overcome amyloid pathologies. The clearance of preformed amyloids and consequently the arresting of the progression of organ deterioration may increase patient survival and quality of life. In this review, we compiled from the literature many examples of chemical and biochemical agents able to disaggregate preformed amyloids, which have been classified as molecular chaperones, chemical chaperones, and pharmacological chaperones. We focused on their mode of action, chemical structure, interactions with the fibrillar structures, morphology and toxicity of the disaggregation products, and the potential use of disaggregation agents as a treatment option in amyloidosis.

N-acetylcysteine attenuates oxidative stress-mediated cell viability loss induced by dimethyl sulfoxide in cryopreservation of human nucleus pulposus cells: A potential solution for mass production

Background

Cell therapy is considered a promising strategy for intervertebral disc (IVD) regeneration. However, cell products often require long-term cryopreservation, which compromises cell viability and potency, thus potentially hindering commercialization and off-the-shelf availability. Dimethyl sulfoxide (DMSO) is a commonly used cryoprotectant, however, DMSO is associated with cytotoxicity and cell viability loss. This study aimed to investigate the effects of DMSO on human nucleus pulposus cells (NPC) and the role of oxidative stress in DMSO-induced cytotoxicity. Furthermore, we examined the potential of antioxidant N-acetylcysteine (NAC) supplementation to mitigate the negative effects of DMSO.

Methods

NPC were exposed to various concentrations of DMSO with or without a freezing cycle. Cell viability, cell apoptosis and necrosis rates, intracellular reactive oxygen species (ROS) levels, and gene expression of major antioxidant enzymes were evaluated. In addition, NAC was added to cryopreservation medium containing 10% DMSO and its effects on ROS levels and cell viability were assessed.

Results

DMSO concentrations ≤1% for 24 h did not significantly affect the NPC viability, whereas exposure to 5 and 10% DMSO (most commonly used concentration) caused cell viability loss (loss of 57% and 68% respectively after 24 h) and cell death in a dose- and time-dependent manner. DMSO increased intracellular and mitochondrial ROS (1.9-fold and 3.6-fold respectively after 12 h exposure to 10% DMSO) and downregulated gene expression levels of antioxidant enzymes in a dose-dependent manner. Tempering ROS through NAC treatment significantly attenuated DMSO-induced oxidative stress and supported maintenance of cell viability.

Conclusions

This study demonstrated dose- and time-dependent cytotoxic effects of DMSO on human NPC. The addition of NAC to the cryopreservation medium ameliorated cell viability loss by reducing DMSO-induced oxidative stress in the freeze-thawing cycle. These findings may be useful for future clinical applications of whole cells and cellular products.

Motor dysfunction in Drosophila melanogaster as a biomarker for developmental neurotoxicity

Adequate alternatives to conventional animal testing are needed to study developmental neurotoxicity (DNT). Here, we used kinematic analysis to assess DNT of known (toluene (TOL) and chlorpyrifos (CPS)) and putative (β-N-methylamino-L-alanine (BMAA)) neurotoxic compounds. Drosophila melanogaster was exposed to these compounds during development and evaluated for survival and adult kinematic parameters using the FlyWalker system, a kinematics evaluation method. At concentrations that do not induce general toxicity, the solvent DMSO had a significant effect on kinematic parameters. Moreover, while TOL did not significantly induce lethality or kinematic dysfunction, CPS not only induced developmental lethality but also significantly impaired coordination in comparison to DMSO. Interestingly, BMAA, which was not lethal during development, induced motor decay in young adult animals, phenotypically resembling aged flies, an effect later attenuated upon aging. Furthermore, BMAA induced abnormal development of leg motor neuron projections. Our results suggest that our kinematic approach can assess potential DNT of chemical compounds.

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Alternatives to mammalian testing are needed to detect developmental neurotoxicity

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The pesticide chlorpyrifos causes partial lethality and motor dysfunction

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Non-lethal levels of BMAA induce motor dysfunction in a dose-dependent manner

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Kinematic profiling of adult Drosophila can identify developmental neurotoxicity

Intracellular K+-Responsive Block Copolymer Micelles for Targeted Drug Delivery of Curcumin

Curcumin (CUR) is a natural bioactive compound that has attracted attention as a “golden molecule” due to its therapeutic properties against several types of tumors. Nonetheless, the antitumor application of CUR is hampered due to its extremely low aqueous solubility and chemical instability. Herein, a novel type of CUR-loaded polymeric micelles with intracellular K⁺-responsive controlled-release properties is designed and developed. The polymeric micelles are self-assembled by poly (N-isopropylacrylamide-co-acryloylamidobenzo-15-crown-5-co-N, N-dimethylacrylamide)-b-DSPE (PNDB-b-DSPE) block copolymers, and CUR. CUR is successfully loaded into the micelles with a CUR loading content of 6.26 wt%. The proposed CUR-PNDB-DSPE polymeric micelles exhibit a significant CUR release in simulated intracellular fluid due to the formation of 2 : 1 ‘‘sandwich’’ host–guest complexes of 15-crown-5 and K⁺, which lead to the hydrophilic outer shell of micelles to collapse and the drug to rapidly migrate out of the micelles. In vitro, the B16F10 cell experiment indicates that CUR-PNDB-DSPE micelles exhibit a high cellular uptake and excellent intracellular drug release in response to the intracellular K⁺ concentration. Moreover, CUR-PNDB-DSPE micelles show high cytotoxicity to B16F10 cells compared to free CUR and CUR-PEG-DSPE micelles. The polymeric micelles with intracellular K⁺-responsive controlled release properties proposed in this study provide a new strategy for designing novel targeted drug delivery systems for CUR delivery for cancer treatment.

Inducing apoptosis using chemical treatment and acidic pH, and detecting it using the Annexin V flow cytometric assay

Cell death is important in physiology, and can happen as a result of structural damage, or as a sequence of programmed cellular processes known as apoptosis. Pathogenic alterations in apoptosis occur in a number of diseases, including cancer, viral infections, autoimmune diseases, immunodeficiencies, and degenerative conditions. Developing accurate and reproducible laboratory methods for inducing and detecting apoptosis is vital for research into these conditions. A number of methods are employed to detect cell death, including DNA fragmentation, the TUNEL assay, and electron microscopy although each has its limitations. Flow cytometry allows for the distinction between live, early apoptotic, late apoptotic and necrotic cells. In this protocol we successfully induce apoptosis using chemical treatment and treatment with low pH in solid tumour cell lines, and have optimized detection using the Annexin V/PI apoptosis assay.

Effect of Escitalopram on the Number of DCX-Positive Cells and NMUR2 Receptor Expression in the Rat Hippocampus under the Condition of NPSR Receptor Blockade

BACKGROUND

Neuropeptide S (NPS) is a multifunctional regulatory factor that exhibits a potent anxiolytic activity in animal models. However, there are no reports dealing with the potential molecular interactions between the activity of selective serotonin reuptake inhibitors (SSRIs) and NPS signaling, especially in the context of adult neurogenesis and the expression of noncanonical stress-related neuropeptides such as neuromedin U (NMU). The present work therefore focused on immunoexpression of neuromedin U receptor 2 (NMUR2) and doublecortin (DCX) in the rat hippocampus after acute treatment with escitalopram and in combination with selective neuropeptide S receptor (NPSR) blockade.

METHODS

Studies were carried out on adult, male Sprague-Dawley rats that were divided into five groups: animals injected with saline (control) and experimental individuals treated with escitalopram (at single dose 10 mg/kg daily), escitalopram + SHA-68, a selective NPSR antagonist (at single dose 40 mg/kg), SHA-68 alone, and corresponding vehicle control. All animals were sacrificed under halothane anaesthesia. The whole hippocampi were quickly excised, fixed, and finally sliced for general qualitative immunohistochemical assessment of the NPSR and NMUR2 expression. The number of immature neurons was enumerated using immunofluorescent detection of doublecortin (DCX) expression within the subgranular zone (SGZ).

RESULTS

Acute escitalopram administration affects the number of DCX and NMUR2-expressing cells in the adult rat hippocampus. A decreased number of DCX-expressing neuroblasts after treatment with escitalopram was augmented by SHA-68 coadministration.

CONCLUSIONS

Early pharmacological effects of escitalopram may be at least partly connected with local NPSR-related alterations of neuroblast maturation in the rat hippocampus. Escitalopram may affect neuropeptide and DCX-expression starting even from the first dose. Adult neurogenesis may be regulated via paracrine neuropeptide S and NMU-related signaling.

Bioinspired Ice-Binding Materials for Tissue and Organ Cryopreservation

Cryopreservation of tissues and organs can bring transformative changes to medicine and medical science. In the past decades, limited progress has been achieved, although cryopreservation of tissues and organs has long been intensively pursued. One key reason is that the cryoprotective agents (CPAs) currently used for cell cryopreservation cannot effectively preserve tissues and organs because of their cytotoxicity and tissue destructive effect as well as the low efficiency in controlling ice formation. In stark contrast, nature has its unique ways of controlling ice formation, and many living organisms can effectively prevent freezing damage. Ice-binding proteins (IBPs) are regarded as the essential materials identified in these living organisms for regulating ice nucleation and growth. Note that controversial results have been reported on the utilization of IBPs and their mimics for the cryopreservation of tissues and organs, that is, some groups revealed that IBPs and mimics exhibited unique superiorities in tissues cryopreservation, while other groups showed detrimental effects. In this perspective, we analyze possible reasons for the controversy and predict future research directions in the design and construction of IBP inspired ice-binding materials to be used as new CPAs for tissue cryopreservation after briefly introducing the cryo-injuries and the challenges of conventional CPAs in the cryopreservation of tissues and organs.

Cryopreservation of undifferentiated and differentiated human neuronal cells

The effective use of human-derived cells that are difficult to freeze, such as parenchymal cells and differentiated cells from stem cells, is crucial. A stable supply of damage-sensitive cells, such as differentiated neuronal cells, neurons, and glial cells can contribute considerably to cell therapy. We developed a serum-free freezing solution that is effective for the cryopreservation of differentiated neuronal cells. The quality of the differentiated and undifferentiated SK-N-SH cells was determined based on cell viability, live-cell recovery rate, and morphology of cultured cells, to assess the efficacy of the freezing solutions. The viability and recovery rate of the differentiated SK-N-SH neuronal cells were reduced by approximately 1.5-folds compared to that of the undifferentiated SK-N-SH cells. The viability and recovery rate of the differentiated SK-N-SH cells were remarkably different between the freezing solutions containing 10% DMSO and that containing 10% glycerol. Cryoprotectants such as fetal bovine serum (FBS), antifreeze proteins (sericin), and sugars (maltose), are essential for protecting against freeze damage in differentiated neuronal cells and parenchymal cells. Serum-free alternatives (sericin and maltose) could increase safety during cell transplantation and regenerative medicine. Considering these, we propose an effective freezing solution for the cryopreservation of neuronal cells.

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The timing of freezing during cell differentiation.

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More effective serum-free freezing solution for differentiated neuronal cells.

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Improving the quality of damage-sensitive cells, such as differentiated neuronal cells.

Hydrophobic Cargo Encapsulation into Virus Protein Cages by Self-Assembly in an Aprotic Organic Solvent

While extensive studies of virus capsid assembly in environments mimicking in vivo conditions have led to an understanding of the thermodynamic driving forces at work, applying this knowledge to virus assembly in other solvents than aqueous buffers has not been attempted yet. In this study, Brome mosaic virus (BMV) capsid proteins were shown to preserve their self-assembly abilities in an aprotic polar solvent, dimethyl sulfoxide (DMSO). This facilitated protein cage encapsulation of nanoparticles and dye molecules that favor organic solvents, such as β-NaYF4-based upconversion nanoparticles and BODIPY dye. Assembly was found to be robust relative to a surprisingly broad range of DMSO concentrations. Cargos with poor initial stability in aqueous solutions were readily encapsulated at high DMSO concentrations and then transferred to aqueous solvents, where they remained stable and preserved their function for months.

DMSO Delays Alzheimer Disease Causing Aβ-induced Paralysis in C. elegans Through Modulation of Glutamate/Acetylcholine Neurotransmission

Background:

Alzheimer’s disease (AD), a prevalent neurodegenerative disease with progressive dementia and neurotransmission (NT)-dysfunction-related complications in older adults, is known to be caused by abnormal Amyloid-β (Aβ) peptide and associated amyloid plaques in the brain. Drugs to cure AD are not in sight. Two major excitatory neurotransmitters, glutamate (Glu) and acetylcholine (ACh), and their signaling systems are implicated in AD.

Objective:

To determine the effect of various NT-altering compounds including fenobam, quisqualic acid, and dimethyl sulfoxide (DMSO) in the protection against Aβ toxicity. Further, to identify the potential mechanism through which the protection happens.

Methods:

The well-known C. elegans AD model, CL4176, in which human Aβ expression is turned on upon a temperature shift to 25 °C that leads to paralysis, was screened for protection/delay in paralysis because of Αβ toxicity. While screening the compounds, dimethyl sulfoxide (DMSO), a universal solvent used to solubilize compounds, was identified to provide protection. Aldicarb and levamisole assays were performed to identify the contribution of ACh neurotransmission in Αβ toxicity protection by DMSO.

Results:

One percent and two percent DMSO delayed paralysis by 48% and 90%, respectively. DMSO was dominant over one of the Glu-NT pathway-related compounds, Fenobam-Group I mGluR antagonist. But DMSO provided only 30% to 50% protection against Quisqualic acid, the Glu-agonist. DMSO (2%) delayed ACh-NT, both presynaptic acetylcholine esterase inhibitor (AchEi)-aldicarb and postsynaptic-iAChR-agonst-levamisole induced paralysis, by ∼70% in CL4176. DMSO seems to be altering Ca²⁺ ion permeability essential for NT as EthyleneDiamine Tetra-Acetic acid (EDTA) and DMSO provided similar aldicarb resistance either combined or alone in wildtype worms. But postsynaptic Ca²⁺ depletion by EDTA could reverse DMSO-induced levamisole hypersensitivity. Surprisingly, the absence of FOrkhead boXO (FOXO) transcription factor homolog, daf-16 (loss-of-function mutant), a critical transcription factor in the reduced IIS-mediated longevity in C. elegans, abolished DMSO-mediated Ald^R.

Conclusion:

DMSO and Fenobam protect against Aβ toxicity through modulation of NT.

Dipropinonates of Sugar Alcohols as Water-Soluble, Nontoxic CPAs for DMSO-Free Cell Cryopreservation

Sorbitol, mannitol, xylitol, and erythritol, four readily available sugar alcohols with poor or no membrane permeability, are converted into their corresponding dipropionates by acylating their primary hydroxyl groups. With enhanced membrane permeability, these diesters are expected to permeate the cell membranes and, upon their hydrolysis, release the corresponding sugar alcohols inside the cells. NIH-3T3 cells incubated with these diesters before being frozen at -80 °C exhibited considerably higher total recovery over those incubated with the free sugar alcohols or media only. Among the four diesters, those of sorbitol, especially mannitol, showed cryoprotective effects comparable to that shown by 5% DMSO. This work has demonstrated the feasibility of converting readily available, naturally occurring compounds into membrane-permeable derivatives that serve as water-soluble, nontoxic alternatives to DMSO.

A New Smoothened Antagonist Bearing the Purine Scaffold Shows Antitumour Activity In Vitro and In Vivo

The Smoothened (SMO) receptor is the most druggable target in the Hedgehog (HH) pathway for anticancer compounds. However, SMO antagonists such as vismodegib rapidly develop drug resistance. In this study, new SMO antagonists having the versatile purine ring as a scaffold were designed, synthesised, and biologically tested to provide an insight to their mechanism of action. Compound 4s was the most active and the best inhibitor of cell growth and selectively cytotoxic to cancer cells. 4s induced cell cycle arrest, apoptosis, a reduction in colony formation and downregulation of PTCH and GLI1 expression. BODIPY-cyclopamine displacement assays confirmed 4s is a SMO antagonist. In vivo, 4s strongly inhibited tumour relapse and metastasis of melanoma cells in mice. In vitro, 4s was more efficient than vismodegib to induce apoptosis in human cancer cells and that might be attributed to its dual ability to function as a SMO antagonist and apoptosis inducer.

Mouse oocyte vitrification with and without dimethyl sulfoxide: influence on cryo-survival, development, and maternal imprinted gene expression

PURPOSE

Oocytes and embryos can be vitrified with and without dimethyl sulfoxide (DMSO). Objectives were to compare no vitrification (No-Vitr), vitrification with DMSO (Vitr + DMSO), and vitrification without DMSO (Vitr - DMSO) on fresh/warmed oocyte survival, induced parthenogenetic activation, parthenogenetic embryo development, and embryonic maternal imprinted gene expression.

METHODS

In this prospective controlled laboratory study, mature B6C3F1 female mouse metaphase II oocytes were treated as: i) No-Vitr, ii) Vitr + DMSO/warmed, and iii) Vitr - DMSO/warmed with subsequent parthenogenetic activation and culture to the blastocyst stage. Oocyte cryo-survival, parthenogenetic activation and embryo development, parthenogenetic embryo maternal imprinted gene expression were outcome measures.

RESULTS

Oocyte cryo-survival was significantly improved in Vitr + DMSO versus Vitr - DMSO at initial warming and 2 h after warming. Induced parthenogenetic activation was similar between all three intervention groups. While early preimplantation parthenogenetic embryo development was similar between control, Vitr + DMSO, Vitr - DMSO oocytes, the development to blastocysts was significantly inferior in the Vitr - DMSO oocytes group compared to the control and Vitr + DMSO oocyte groups. Finally, maternal imprinted gene expression was similar between intervention groups at both the 2-cell and blastocyst parthenogenetic embryo stage.

CONCLUSION(S)

Inclusion of DMSO in oocyte vitrification solutions improved cryo-survival and developmental potential of parthenogenetic embryos to the blastocyst stage without significantly altering maternal imprinted gene expression.

Exposure to DMSO during infancy alters neurochemistry, social interactions, and brain morphology in long-evans rats

INTRODUCTION

Dimethyl sulfoxide (DMSO) is a widely used solvent to dissolve hydrophobic substances for clinical uses and experimental in vivo purposes. While usually regarded safe, our prior studies suggest changes to behavior following DMSO exposure. We therefore evaluated the effects of a five-day, short-term exposure to DMSO on postnatal infant rats (P6-10).

METHODS

DMSO was intraperitoneally injected for five days at 0.2, 2.0, and 4.0 ml/kg body mass. One cohort of animals was sacrificed 24 hr after DMSO exposure to analyze the neurometabolic changes in four brain regions (cortex, hippocampus, basal ganglia, and cerebellum) by hydrophilic interaction liquid chromatography. A second cohort of animals was used to analyze chronic alterations to behavior and pathological changes to glia and neuronal cells later in life (P21-P40).

RESULTS

164 metabolites, including key regulatory molecules (retinoic acid, orotic acid, adrenic acid, and hypotaurine), were found significantly altered by DMSO exposure in at least one of the brain regions at P11 (p < .05). Behavioral tests showed significant hypoactive behavior and decreased social habits to the 2.0 and 4.0 ml DMSO/kg groups (p < .01). Significant increases in number of microglia and astrocytes at P40 were observed in the 4.0 ml DMSO/kg group (at p < .015.) CONCLUSIONS: Despite short-term exposure at low, putatively nontoxic concentrations, DMSO led to changes in behavior and social preferences, chronic alterations in glial cells, and changes in essential regulatory brain metabolites. The chronic neurological effects of DMSO exposure reported here raise concerns about its neurotoxicity and consequent safety in human medical applications and clinical trials.

Advanced Nanomaterials-Assisted Cell Cryopreservation: A Mini Review

Cell cryopreservation is of vital significance both for transporting and storing cells before experimental/clinical use. Cryoprotectants (CPAs) are necessary additives in the preserving medium in cryopreservation, preventing cells from freeze-thaw injuries. Traditional organic solvents have been widely used in cell cryopreservation for decades. Given the obvious damage to cells due to their undesirable cytotoxicity and the burdensome post-thaw washing cycles before use, traditional CPAs are more and more likely to be replaced by modern ones with lower toxicity, less processing, and higher efficiency. As materials science thrives, nanomaterials are emerging to serve as potent vehicles for delivering nontoxic CPAs or inherent CPAs comparable to or even superior to conventional ones. This review will introduce some advanced nanomaterials (e.g., organic/inorganic nanoCPAs, nanodelivery systems) utilized for cell cryopreservation, providing broader insights into this developing field.

Cryopreservation of human cerebral microvascular endothelial cells and astrocytes in suspension and monolayers

The blood-brain barrier (BBB) keeps pathogens and toxins out of the brain but also impedes the entry of pharmaceuticals. Human cerebral microvascular endothelial cells (hCMECs) and astrocytes are the main functional cell components of the BBB. Although available commercially as cryopreserved cells in suspension, improvements in their cryopreservation and distribution as cryopreserved monolayers could enhance BBB in vitro studies. Here, we examined the response to slow cooling and storage in liquid nitrogen of immortalized hCMEC/D3 cells and human primary astrocytes in suspension and in monolayers. HCMEC/D3 cells in suspension cryopreserved in 5% dimethyl sulfoxide (DMSO) and 95% fetal bovine serum or in 5% DMSO and 6% hydroxyethyl starch (HES) showed post-thaw membrane integrities above 90%, similar to unfrozen control. Cryopreservation did not affect the time-dependent ability of hCMEC/D3 cells to form tubes on Matrigel. Primary astrocytes in suspension cryopreserved in the presence of 5% DMSO and 6% HES had improved viability over those cryopreserved in 10% DMSO. Monolayers of single cultures or co-cultures of hCMEC/D3 cells and astrocytes on fibronectin-coated Rinzl coverslips retained membrane integrities and metabolic function, after freezing in 5% DMSO, 6% HES, and 2% chondroitin sulfate, that were comparable to those of unfrozen controls even after overnight incubation. Rinzl is better than glass or Thermanox as an underlying solid substrate for cryopreserving hCMEC/D3 monolayers. Cryopreserved hCMEC/D3 monolayers expressed the junction proteins ZO-1 and claudin-5 similar to their unfrozen counterparts. Hence, we describe improved cryopreservation protocols for hCMEC/D3 cells and astrocytes in suspension, and a novel protocol for the cryopreservation of monolayers of hCMEC/D3 cells and astrocytes as single cultures or co-cultures that could expand their distribution for research on disease modeling, drug screening, and targeted therapy pertaining to the BBB.

Resveratrol and Its Analogs as Functional Foods in Periodontal Disease Management

Periodontitis is a common chronic inflammatory disease driven by the interaction between a dysbiotic oral microbiome and the dysregulated host immune-inflammatory response. Naturally derived nutraceuticals, such as resveratrol and its analogs, are potential adjunctive therapies in periodontal treatment due to their antimicrobial and anti-inflammatory properties. Furthermore, different analogs of resveratrol and the choice of solvents used may lead to varying effects on therapeutic properties. This review presents the current findings and gaps in our understanding on the potential utility of resveratrol and its analogs in periodontal treatment.

Cryopreservation of Cyanobacteria and Eukaryotic Microalgae Using Exopolysaccharide Extracted from a Glacier Bacterium

Exopolysaccharide (EPS) has been known to be a good cryoprotective agent for bacteria, but it has not been tested for cyanobacteria and eukaryotic microalgae. In this study, we used EPS extracted from a glacier bacterium as a cryoprotective agent for the cryopreservation of three unicellular cyanobacteria and two eukaryotic microalgae. Different concentrations of EPS (10%, 15%, and 20%) were tested, and the highest concentration (20%) of EPS yielded the best growth recovery for the algal strains we tested. We also compared EPS with 5% dimethyl sulfoxide (DMSO) and 10% glycerol for the cryopreservation recovery. The growth recovery for the microalgal strains after nine months of cryopreservation was better than 5% DMSO, a well-known cryoprotectant for microalgae. A poor recovery was recorded for all the tested strains with 10% glycerol as a cryoprotective agent. The patterns of growth recovery for most of these strains were similar after 5 days, 15 days, and 9 months of cryopreservation. Unlike common cryopreservants such as DMSO or methanol, which are hazardous materials, EPS is safe to handle. We demonstrate that the EPS from a psychrotrophic bacterium helped in the long-term cryopreservation of cyanobacteria and microalgae, and it has the potential to be used as natural cryoprotective agent for other cells.

Enhancing transient protein expression in HEK-293 cells by briefly exposing the culture to DMSO

BACKGROUND

Transient expression of proteins in mammalian cells is a key technique for many functional and structural studies of human and higher eukaryotic genes as well as for the production of recombinant protein therapeutics. Maximizing the expression efficiency to achieve a higher expression yield is desirable and may be even critical when, for instance, an expressed protein must be characterized at the single-cell level.

NEW METHODS

Our goal was to develop a simple method by which protein expression yield in human embryonic kidney (HEK)-293 cells could be enhanced with a brief treatment of dimethyl sulfoxide (DMSO) solution.

RESULTS

By expressing green fluorescent protein (GFP) as a reporter protein using the calcium phosphate transfection method and imaging a large population of cells, we found that a 5-min exposure of 10 % DMSO to HEK-293 cells, 4 h after transfection of the protein of interest, leads to ∼1.6-fold increase in the expression yield without causing any appreciable cytotoxicity. By expressing an α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and separately a kainate receptor in HEK-293 cells and measuring glutamate-induced whole-cell current response, we also found that such a brief DMSO treatment did not affect channel activity.

CONCLUSION

This method is simple, efficient and inexpensive to use for enhancing transient transfection yield in HEK-293 cells.

A Rational Insight into the Effect of Dimethyl Sulfoxide on TNF-α Activity

Direct inhibition of tumor necrosis factor-alpha (TNF-α) action is considered a promising way to prevent or treat TNF-α-associated diseases. The trimeric form of TNF-α binds to its receptor (TNFR) and activates the downstream signaling pathway. The interaction of TNF-α with molecular-grade dimethyl sulfoxide (DMSO) in an equal volumetric ratio renders TNF-α inert, in this state, TNF-α fails to activate TNFR. Here, we aimed to examine the inhibition of TNF-α function by various concentrations of DMSO. Its higher concentration led to stronger attenuation of TNF-α-induced cytokine secretion by fibroblasts, and of their death. We found that this inhibition was mediated by a perturbation in the formation of the functional TNF-α trimer. Molecular dynamics simulations revealed a transient interaction between DMSO molecules and the central hydrophobic cavity of the TNF-α homodimer, indicating that a brief interaction of DMSO with the TNF-α homodimer may disrupt the formation of the functional homotrimer. We also found that the sensitizing effect of actinomycin D on TNF-α-induced cell death depends upon the timing of these treatments and on the cell type. This study will help to select an appropriate concentration of DMSO as a working solvent for the screening of water-insoluble TNF-α inhibitors.

GC-MS Evaluation, Antioxidant Content, and Cytotoxic Activity of Propolis Extract from Peninsular Malaysian Stingless Bees, Tetrigona Apicalis

INTRODUCTION

Propolis has been used traditionally in several countries for treating various diseases as it possessed healing properties including antioxidant and anticancer qualities. In Peninsular Malaysia, Tetrigona apicalis is one of the species of stingless bees mainly found in virgin jungle reserves which largely contribute to propolis production. Therefore, this study is designed to evaluate the phytochemical contents, antioxidant properties, and the cytotoxic effect of ethanolic crude of propolis extract against MCF7 and MCF 10A cell lines.

METHOD

The ethanolic extract of propolis (EEP) was extracted using 80% ethanol. Identification of phytochemical contents and antioxidant properties of EEP was analysed by gas chromatography-mass spectrometry (GC-MS) and using 2, 2'-azinobis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) method, respectively. The EEP cytotoxic activity was evaluated on MCF7 and MCF 10A using 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay.

RESULTS

Phytochemical contents of EEP demonstrated 28 compounds in which caryophyllene (99%), β-amyrin (96%), α-amyrin (93%), and caryophyllene oxide (93%) were the main compounds. The percentage of ABTS+ scavenging activity of EEP showed an inhibition of 9.5% with half-inhibitory concentration (IC50) value of 1.68 mg/mL. The EEP reduced MCF7 cells viability at IC50 value of 62.24 μg/mL, 44.15 μg/mL, and 32.70 μg/mL at 24, 48, and 72 hours, respectively. The IC50 value of MCF 10A was 49.55 μg/mL, 56.05 μg/mL, and 72.10 μg/mL at 24, 48, and 72 hours, respectively. The EEP cytotoxic effect of T. apicalis was more selective towards MCF7 at 72-hour incubation with a selectivity index (SI) of 2.20.

CONCLUSION

The EEP has been shown to have antioxidants and potential bioactive compounds and inhibited proliferation of the MCF7 cells. Further studies on the EEP role in the apoptosis pathway and its screening towards other cell lines will be evaluated.

Minoxidil Cannot Be Used To Target Lysyl Hydroxylases during Postnatal Mouse Lung Development: A Cautionary Note

The lysyl hydroxylases (procollagen-lysine 5-dioxygenases) PLOD1, PLOD2, and PLOD3 have been proposed as pathogenic mediators of stunted lung development in bronchopulmonary dysplasia (BPD), a common complication of preterm birth. In affected infants, pulmonary oxygen toxicity stunts lung development. Mice lacking Plod1 exhibit 15% mortality, and mice lacking Plod2 or Plod3 exhibit embryonic lethality. Therefore, to address any pathogenic role of lysyl hydroxylases in stunted lung development associated with BPD, minoxidil was administered to newborn mice in an oxygen toxicity-based BPD animal model. Minoxidil, which has attracted much interest in the management of systemic hypertension and androgenetic alopecia, can also be used to reduce lysyl hydroxylase activity in cultured cells. An in vivo pilot dosing study established 50 mg⋅kg-1⋅day-1 as the maximum possible minoxidil dose for intraperitoneal administration in newborn mouse pups. When administered at 50 mg⋅kg-1⋅day-1 to newborn mouse pups, minoxidil was detected in the lungs but did not impact lysine hydroxylation, collagen crosslinking, or lysyl hydroxylase expression in the lungs. Consistent with no impact on mouse lung extracellular matrix structures, minoxidil administration did not alter the course of normal or stunted lung development in newborn mice. At doses of up to 50 mg⋅kg⋅day-1, pharmacologically active concentrations of minoxidil were not achieved in neonatal mouse lung tissue; thus, minoxidil cannot be used to attenuate lysyl hydroxylase expression or activity during mouse lung development. These data also highlight the need for new and specific lysyl hydroxylase inhibitors. SIGNIFICANCE STATEMENT: Extracellular matrix crosslinking is mediated by lysyl hydroxylases, which generate hydroxylated lysyl residues in procollagen peptides. Deregulated collagen crosslinking is a pathogenic component of a spectrum of diseases, and thus, there is interest in validating lysyl hydroxylases as pathogenic mediators of disease and potential "druggable" targets. Minoxidil, administered at the maximum possible dose, did not inhibit lysyl hydroxylation in newborn mouse lungs, suggesting that minoxidil was unlikely to be of use in studies that pharmacologically target lysyl hydroxylation in vivo.

Characterization of adherent primary cell lines from fresh human glioblastoma tissue, defining glial fibrillary acidic protein as a reliable marker in establishment of glioblastoma cell culture

BACKGROUND

Primary adherent glioblastoma cell lines are an important tool in investigating cellular and molecular tumor biology, as well as treatment options for patients.

AIM

The phenotypical and immunocytochemical characterization of primary cell lines from glioblastoma specimens during establishment is of great importance, in order to reliably identify these cell lines as primary glioblastoma cell lines.

METHODS AND RESULTS

Sixteen primary adherent cell lines out of 34 glioblastoma samples (47%) were established and further characterized. For phenotypical characterization, morphology and growth characteristics of the cells were classified. The cell lines had a high growth rate with a doubling time of 2 to 14 days. Morphologically, the cells displayed spindle-form or polygonal to amorphous shapes and grow as monolayer or in foci without evidence of contact inhibition. The cells were able to migrate and to form colonies. For further characterization, the protein expression of the astrocyte-specific protein glial fibrillary acidic protein (GFAP), the glial marker S100B, the neuronal marker TUBB3, and malignancy marker VIM, as well as the progenitor markers NES and SOX2, the proliferation marker MKI67, and the fibroblast marker TE7 were determined. Based on the immunocytochemical validation criterion of a coexpression of GFAP and S100B, 15 out of these 16 cell lines (94%) were defined as primary glioblastoma cell lines (pGCL). All 15 pGCL expressed TUBB3 and VIM. NES and SOX2 were stained positively in 13/15 and 6/15 pGCL. MKI67 was expressed in 11/15 and TE7 in 2/15 pGCL.

CONCLUSION

These results point out that in self-established primary adherent glioblastoma cell lines, the expression of the specific astrocytic and glial markers GFAP and S100B and of the malignancy and progenitor markers VIM, NES, and SOX2 has to be validated. These data show that primary cell lines of glioblastoma origin with high malignant potential are reliably to establish using standardized validation criteria.

Mechanisms underlying dimethyl sulfoxide-induced cellular migration in human normal hepatic cells

Numerous studies have reported that low-dose dimethyl sulfoxide (DMSO, <1.5%, v/v) can interfere with various cellular processes, such as cell proliferation, differentiation, apoptosis, and cycle. By contrast, minimal information is available about the effect of low-dose DMSO on cell migration. Here, we report the effect of DMSO (0.0005%-0.5%, v/v) on cellular migration in human normal hepatic L02 cells. We used the Cell Counting Kit-8 assay to measure cell viability, scratch wound healing assay to observe cellular migration, flow cytometry to analyze cell cycle and death pattern, reverse transcription quantitative polymerase chain reaction to evaluate mRNA expression, and Western blot to detect protein levels. After treatment with 0.0005% (v/v) DMSO, more cells entered S phase arrest, the MMP1/TIMP1 ratio increased, and HSP27 expression was elevated. After treatment with 0.1% (v/v) DMSO, more cells entered G0/G1 phase arrest, the MMP2/TIMP2 ratio increased, the p-p38 and p-Smad3 signaling pathways were activated, and neuropilin-1 expression was elevated. These results showed that cells migrate when their MMP1/TIMP1 and MMP2/TIMP2 ratios are imbalanced. Such migration is modulated by the p38/HSP27 signaling pathway and TGF-β/Smad3 dependent signaling pathway.

Control of stress-induced apoptosis by freezing tolerance-associated wheat proteins during cryopreservation of rat hepatocytes

Cryopreservation is used for long-term storage of cells and tissues. Cryoprotectants such as dimethyl disulfoxide (DMSO) are used to protect cells against freeze-thaw damage. Despite the use of cryoprotectants, hepatocytes are sensitive to stresses imposed by freeze and thaw processes, which cause physical damage, loss of functionality, or cell death. As an alternative, we have developed new technology using several recombinant wheat proteins as cryoprotectants: TaENO (enolase), TaBAS1 (2-Cys peroxiredoxin), and a combination of WCS120 (dehydrin) with TaIRI-2 (inhibitor of ice recrystallization). This study aims to understand the mechanisms by which these plant proteins protect rat hepatocytes against cell death incurred during cryopreservation. Our analysis revealed that for cells cryopreserved with DMSO, cell death occurred by apoptosis and necrosis. Apoptosis was detected by activation of effector caspases-3 and -7, PARP cleavage, and nuclear chromatin condensation. These apoptotic events were inhibited when hepatocytes were cryopreserved with the different plant proteins. Cryopreservation with DMSO activated apoptosis through the mitochondrial pathway: the Bax/Bcl-2 protein ratio increased, mitochondrial membrane potential decreased, and initiator caspase-9 was activated. Furthermore, the endoplasmic reticulum pathway of apoptosis was activated: levels of the chaperone Bip/GRP78 decreased, pro-apoptotic transcription factor CHOP was induced, and initiator caspase-12 was activated. Activation of the mitochondrial and endoplasmic reticulum pathways of apoptosis was attenuated when hepatocytes were cryopreserved with the different recombinant proteins. This study improves understanding of mechanisms of cryoprotection provided by these plant proteins during freezing stress. These proteins are natural products and show promising potential by decreasing cell death during cryopreservation of hepatocytes.

Characterization of a liposomal copper(II)-quercetin formulation suitable for parenteral use

Quercetin (3,3',4',5,7-pentahydroxyflavone) is a naturally derived flavonoid that is commonly found in fruits and vegetables. There is mounting evidence to suggest that quercetin has potential anticancer effects and appears to interact synergistically when used in combination with approved chemotherapeutic agents such as irinotecan and cisplatin. Unfortunately, quercetin has shown limited clinical utility, partly due to low bioavailability related to its poor aqueous solutions (< 10 μg/mL). In this study, liposomal formulations of quercetin were developed by exploiting quercetin's ability to bind copper. Quercetin powder was added directly to pre-formed copper-containing liposomes (2-distearoyl-sn-glycero-3-phosphocholine (DSPC) and cholesterol (CHOL) (55:45 M ratio)). As a function of time and temperature, the formation of copper-quercetin was measured. Using this methodology, a final quercetin-to-lipid (mol:mol) ratio of 0.2 was achievable and solutions containing quercetin at concentrations of > 5 mg/mL were attained, representing at least a > 100-fold increase in apparent solubility. The resulting formulation was suitable for intravenous dosing with no overt toxicities when administered at doses of 50 mg/kg in mice. Pharmacokinetic studies demonstrated that the copper-quercetin formulations had an AUC_0-24H of 8382.1 μg h/mL when administered to mice at 50 mg/kg. These studies suggested that quercetin (not copper-quercetin) dissociates from the liposomes after administration. The resulting formulation is suitable for further development and also serves as a proof-of-concept for formulating other flavonoids and flavonoid-like compounds. Given that quercetin exhibits an IC₅₀ of >10 μM when tested against cancer cell lines, we believe that the utility of this novel quercetin formulation for cancer indications will ultimately be as a component of a combination product.