Cell-Based Regenerative Endodontics for the Treatment of Irreversible Pulpitis: AnIn VivoInvestigation

INTRODUCTION

This study aims to investigate the ability of umbilical cord mesenchymal stem cells (UC-MSC) to enhance the regeneration of pulp-dentin complex in immature permanent teeth with irreversible pulpitis.

METHODS

A total of 32 mandibular premolar teeth with immature apices in 5 dogs were used in this in-vivo randomized controlled trial (RCT). Eight healthy teeth without pre-existing pathosis served as the positive control samples and received no treatment, while in another 8 teeth, the pulp was completely extirpated (negative control). Class V cavities were prepared to induce inflammation in the remaining 16 teeth (groups 3 and 4) and the pulp was extirpated 2-4 mm short of the radiographic apex. Of the 16, the 8 teeth in group 4 received 1 mL of cord blood stem cells with a hydrogel scaffold. Blood clots were covered with mineral trioxide aggregates at the cementoenamel junction in the experimental groups, and teeth were filled with RMGI and composite. Three months later, block sections were removed for histologic evaluations for the evaluation of postoperative apical closure, degree of inflammation, and presence of normal pulp tissue. The data were statistically analyzed with the chi-square test (P < .05).

RESULTS

All teeth with complete pulp extirpation demonstrated pulpal necrosis with no postoperative closure of their apices, while apical closure was seen in all the teeth in the remaining groups. There was a statistically significant (P < .001) difference in the presence of inflammation and normal pulp tissue between the experimental groups. The teeth in group 3 showed normal pulp tissue extending to the level of MTA, but there was inflammation within the canal space. In contrast, the teeth in the UC-MSC group demonstrated organized, normal pulp tissue with no inflammation.

CONCLUSION

Based on these results, the regeneration of the pulp-dentin complex is possible with no inflammation when UC-MSCs are used and 2-4 mm of the apical pulp remains intact in immature teeth with irreversible pulpitis.

In vitro modulator responsiveness of 655 CFTR variants found in people with cystic fibrosis

BACKGROUND

In 2017, the US Food and Drug Administration initiated expansion of drug labels for the treatment of cystic fibrosis (CF) to include CF transmembrane conductance regulator (CFTR) gene variants based on in vitro functional studies. This study aims to identify CFTR variants that result in increased chloride (Cl-) transport function by the CFTR protein after treatment with the CFTR modulator combination elexacaftor/tezacaftor/ivacaftor (ELX/TEZ/IVA). These data may benefit people with CF (pwCF) who are not currently eligible for modulator therapies.

METHODS

Plasmid DNA encoding 655 CFTR variants and wild-type (WT) CFTR were transfected into Fisher Rat Thyroid cells that do not natively express CFTR. After 24 h of incubation with control or TEZ and ELX, and acute addition of IVA, CFTR function was assessed using the transepithelial current clamp conductance assay. Each variant's forskolin/cAMP-induced baseline Cl- transport activity, responsiveness to IVA alone, and responsiveness to the TEZ/ELX/IVA combination were measured in three different laboratories. Western blots were conducted to evaluate CFTR protein maturation and complement the functional data.

RESULTS AND CONCLUSIONS

253 variants not currently approved for CFTR modulator therapy showed low baseline activity (<10 % of normal CFTR Cl- transport activity). For 152 of these variants, treatment with ELX/TEZ/IVA improved the Cl- transport activity by ≥10 % of normal CFTR function, which is suggestive of clinical benefit. ELX/TEZ/IVA increased CFTR function by ≥10 percentage points for an additional 140 unapproved variants with ≥10 % but <50 % of normal CFTR function at baseline. These findings significantly expand the number of rare CFTR variants for which ELX/TEZ/IVA treatment should result in clinical benefit.

Synthesis and molecular characterization of levan produced by immobilized Microbacterium paraoxydans

In this study, we report high molecular weight (HMW) levan production by whole cells of Microbacterium paraoxydans, previously reported to be a good producer of fructooligosaccharides. Structural analysis of the extracellularly produced fructan indicated the glycosidic bonds between the adjacent fructose to be of β-(2, 6) linkage with over 90% of the fructan to have molecular weight around 2 × 108 Da and 10% with a molecular weight of ∼20 kDa. Immobilization of the cells in Ca-alginate led to the production of 44.6 g/L levan with a yield of 0.29 g/g sucrose consumed. Factors affecting the conversion rate were identified by One-Factor-At-a-Time (OFAT) analysis and the combination of these (initial sucrose concentration of 400 g/L, 100 mM buffer pH 7, the temperature of 37 °C and 20 mM CaCl2) led to the production of ∼129 g/L of levan with a yield of ∼0.41 g/g sucrose consumed and volumetric productivity of 1.8 g/L/h.

High throughput screening for drugs that inhibit 3C-like protease in SARS-CoV-2

The SARS coronavirus 2 (SARS-CoV-2) pandemic remains a major problem in many parts of the world and infection rates remain at extremely high levels. This high prevalence drives the continued emergence of new variants, and possibly ones that are more vaccine-resistant and that can drive infections even in highly vaccinated populations. The high rate of variant evolution makes clear the need for new therapeutics that can be clinically applied to minimize or eliminate the effects of COVID-19. With a hurdle of 10 years, on average, for first in class small molecule therapeutics to achieve FDA approval, the fastest way to identify therapeutics is by drug repurposing. To this end, we developed a high throughput cell-based screen that incorporates the essential viral 3C-like protease and its peptide cleavage site into a luciferase complementation assay to evaluate the efficacy of known drugs encompassing approximately 15,000 clinical-stage or FDA-approved small molecules. Confirmed inhibitors were also tested to determine their cytotoxic properties. Medicinal chemistry efforts to optimize the hits identified Tranilast as a potential lead. Here, we report the rapid screening and identification of potentially relevant drugs that exhibit selective inhibition of the SARS-CoV-2 viral 3C-like protease.

Extru-seq: a method for predicting genome-wide Cas9 off-target sites with advantages of both cell-based and in vitro approaches

We present a novel genome-wide off-target prediction method named Extru-seq and compare it with cell-based (GUIDE-seq), in vitro (Digenome-seq), and in silico methods using promiscuous guide RNAs with large numbers of valid off-target sites. Extru-seq demonstrates a high validation rate and retention of information about the intracellular environment, both beneficial characteristics of cell-based methods. Extru-seq also shows a low miss rate and could easily be performed in clinically relevant cell types with little optimization, which are major positive features of the in vitro methods. In summary, Extru-seq shows beneficial features of cell-based and in vitro methods.

Disruption in the meat industry: new technologies in nonmeat substitutes

After World War II, consumer patterns of food consumption changed dramatically. Initially, it was mobility, economic evolution, and home appliance technologies that induced a shift toward meals eaten outside of the home and to ready-to-eat foods at home. More recently, health concerns and sustainability issues shifted consumer tastes among meat products and gave rise to a change in attitudes about raising animals for human consumption. On the supply side, new technologies in nonmeat production enabled new producers, most notably Impossible Foods and Beyond Meat, to enter as fringe competitors to vertically integrated, oligopolistic meat processors. Today, these nonmeat products represent a small, but growing, share of consumer expenditures at grocery stores, restaurants, and direct-to-consumer delivery channels. In this paper, we evaluate the disruption of the traditional meat industry through the lens of consumer spending trends and substitution among meat products and find that the development of alternative meat products is market-driven rather than policy-driven. Given these findings, we identify implications for product development and industrial organization.

Cell-based treatment options facilitate regeneration of cartilage, ligaments and meniscus in demanding conditions of the knee by a whole joint approach

PURPOSE

This article provides an update on the current therapeutic options for cell-based regenerative treatment of the knee with a critical review of the present literature including a future perspective on the use of regenerative cell-based approaches. Special emphasis has been given on the requirement of a whole joint approach with treatment of comorbidities with aim of knee cartilage restoration, particularly in demanding conditions like early osteoarthritis.

METHODS

This narrative review evaluates recent clinical data and published research articles on cell-based regenerative treatment options for cartilage and other structures around the knee RESULTS: Cell-based regenerative therapies for cartilage repair have become standard practice for the treatment of focal, traumatic chondral defects of the knee. Specifically, matrix-assisted autologous chondrocyte transplantation (MACT) shows satisfactory long-term results regarding radiological, histological and clinical outcome for treatment of large cartilage defects. Data show that regenerative treatment of the knee requires a whole joint approach by addressing all comorbidities including axis deviation, instability or meniscus pathologies. Further development of novel biomaterials and the discovery of alternative cell sources may facilitate the process of cell-based regenerative therapies for all knee structures becoming the gold standard in the future.

CONCLUSION

Overall, cell-based regenerative cartilage therapy of the knee has shown tremendous development over the last years and has become the standard of care for large and isolated chondral defects. It has shown success in the treatment of traumatic, osteochondral defects but also for degenerative cartilage lesions in the demanding condition of early OA. Future developments and alternative cell sources may help to facilitate cell-based regenerative treatment for all different structures around the knee by a whole joint approach.

LEVEL OF EVIDENCE

IV.

Biofluidic material-based carriers: Potential systems for crossing cellular barriers

Biofluids act as a repository for disease biomarkers and are excellent diagnostic tools applied in establishing a disease profile based on clinical testing, evaluation and monitoring the progression of patients suffering from various conditions. Furthermore, biofluids and their derived components such proteins, pigments, enzymes, hormones and cells carry a potential in the development of therapeutic drug delivery systems or as cargo materials for targeting the drug to the site of action. The presence of biofluids with respect to their specific location reveals the information of disease progression and mechanism, delivery aspects such as routes of administration as well as pharmacological factors such as binding affinity, rate of kinetics, efficacy, bioavailability and patient compliance. This review focuses on the properties and functional benefits of some biofluids, namely blood, saliva, bile, urine, amniotic fluid, synovial fluid and cerebrospinal fluid. It also covers the therapeutic and targeting action of fluid-derived substances in various micro- or nano-systems like nanohybrids, nanoparticles, self-assembled micelles, microparticles, cell-based systems, etc. The formulation of such biologically-oriented systems demonstrate the advantages of natural origin, biocompatibility and biodegradability and offer new techniques for overcoming the challenges experienced in conventional therapies.

Advantages and shortcomings of cell-based electrical impedance measurements as a GPCR drug discovery tool. Biosens Bioelectron. 2019;137:33-44. [PMID: 31077988 DOI: 10.1016/j.bios.2019.04.041]

G Protein-Coupled Receptors (GPCRs) transduce extracellular signals and activate intracellular pathways, usually through activating associated G proteins. Due to their involvement in many human diseases, they are recognized worldwide as valuable drug targets. Many experimental approaches help identify small molecules that target GPCRs, including in vitro cell-based reporter assays and binding studies. Most cell-based assays use one signaling pathway or reporter as an assay readout. Moreover, they often require cell labeling or the integration of reporter systems. Over the last decades, cell-based electrical impedance biosensors have been explored for drug discovery. This label-free method holds many advantages over other cellular assays in GPCR research. The technology requires no cell manipulation and offers real-time kinetic measurements of receptor-mediated cellular changes. Instead of measuring the activity of a single reporter, the impedance readout includes information on multiple signaling events. This is beneficial when screening for ligands targeting orphan GPCRs since the signaling cascade(s) of the majority of these receptors are unknown. Due to its sensitivity, the method also applies to cellular models more relevant to disease, including patient-derived cell cultures. Despite its advantages, remaining issues regarding data comparability and interpretability has limited implementation of cell-based electrical impedance (CEI) in drug discovery. Future optimization must include both full exploitation of CEI response data using various ways of analysis as well as further exploration of its potential to detect biased activities early on in drug discovery. Here, we review the contribution of CEI technology to GPCR research, discuss its comparative benefits, and provide recommendations.

In vitro methods for testing antiviral drugs

Despite successful vaccination programs and effective treatments for some viral infections, humans are still losing the battle with viruses. Persisting human pandemics, emerging and re-emerging viruses, and evolution of drug-resistant strains impose continuous search for new antiviral drugs. A combination of detailed information about the molecular organization of viruses and progress in molecular biology and computer technologies has enabled rational antivirals design. Initial step in establishing efficacy of new antivirals is based on simple methods assessing inhibition of the intended target. We provide here an overview of biochemical and cell-based assays evaluating the activity of inhibitors of clinically important viruses.

Establishment of engineered cell-based assays mediating LAG3 and PD1 immune suppression enables potency measurement of blocking antibodies and assessment of signal transduction

LAG3 is an important regulator of T cell homeostasis and studies in mouse tumor models have demonstrated that simultaneously antagonizing LAG3 and PD1 can augment tumor-specific T cell responses and induce tumor rejection. The combined use of LAG3 antagonist antibodies with established anti-PD1 therapies is currently being evaluated in human clinical trials. A functional assay for human LAG3 was developed by co-culture of a Jurkat T-cell lymphoma line overexpressing LAG3 with a Raji B-cell lymphoma line in the presence of staphylococcal enterotoxins. Reversal of LAG3 repression was measured as an increase in IL-2 production or NFAT activation in response to treatment with MK-4280, an anti-human LAG3 antagonist antibody. Changes in cytokines, chemokines, and other mRNA transcripts were in agreement with published in vitro and in vivo models for LAG3 biology which highlights the physiological relevance of the Jurkat functional assay. Additional engineering of PD1 and PDL1 components into the LAG3 assay resulted in a bi-functional assay that is capable of inducing a 10-fold response to individual antibodies blocking either PD1 or LAG3. Importantly, when MK-4280 and pembrolizumab were combined to block both pathways, a synergistic 50-fold increase in response was observed.

Label-Free Cell-Based Assay for Characterization of Biomolecules and Receptors

We present a method to study the interaction between biomolecules and receptors present on the cell surface. This enables studies of molecular interactions in a natural biological context. As the analyte interacts with the receptors still intact on the cell surface, the experimental data provides complete dynamics and complexity of the interaction, thereby generating highly informative data. Attana's cell-based biosensor platform can be used to obtain this information from a diverse range of interactions as described in these protocols, which detail how to grow or capture cells on a surface, how to stabilize and visualize the cells on the surface, and how to set up assays to measure detailed interaction kinetics directly on the cell surface.

Studying TDP1 Function in DNA Repair

Topoisomerase poisons act by inducing abortive topoisomerase reactions, which generate stable protein-DNA breaks (PDBs) that interfere with transcription elongation and progression of replication forks. In vertebrates, Tyrosyl-DNA phosphodiesterase 1 (TDP1) plays a major role in removal of topoisomerase 1-associated PDBs in the nucleus and mitochondria by hydrolyzing the 3'-phosphotyrosine bond. Depletion of TDP1 sensitizes tumor cells with defective DNA repair capacity to the genotoxic effect of TOP1 poisons, while homozygous mutation of the catalytic residue of TDP1 is associated with cerebellar degeneration and ataxia. We describe here two fluorescence based biochemical assays for measuring TDP1 phosphodiesterase activity in cellular lysates. The Gyrasol assay is sensitive, high-throughput, and useful for screening potential TDP1 inhibitors or cell lines that are likely to develop resistance to TOP1 poisons. The gel-shift assay is low cost and simple to set up, and is also suitable for screening cell lines that are likely to develop resistance to TOP1 poisons, as well as for diagnostic screening for individuals with hereditary ataxias.

In vitro Metabolomic Approaches to Investigating the Potential Biological Effects of Phenolic Compounds: An Update

Dietary phenolic compounds (PCs) have been receiving interest for their presumed roles in disease prevention. However, there is a lack of studies on the underlying molecular mechanisms. In this regard, in vitrometabolomic approaches are suitable for the investigation of the molecular changes in response to PC exposure. Up to date, the biological effects of PCs have only been examined for PCs from rosemary (Rosmarinus officinalis), olive oil, and resveratrol using cell-based metabolomic approach, although transcriptomic and/or proteomic studies have also been conducted in the same in vitro cell experiment in some cases. Our integral analysis of the reviewed studies suggest that PCs may be involved not only in basic cellular processes or macro- and micro-nutrient metabolism, but also in specific metabolic pathways that have been thoroughly investigated. These modulated pathways could have a clinical impact on neurodegenerative diseases, type 2 diabetes, cancer, and cardiovascular diseases. In conclusion, the in vitro metabolomic approaches provide additional information of the molecular mechanisms involved in disease risk reduction of dietary PCs. In order to elucidate the mechanisms of action of PCs, more metabolomic cell-based studies are needed and testing the physiological conjugated forms of PCs in these cell systems could be of special interest.

Identification and elimination of target-related matrix interference in a neutralizing anti-drug antibody assay

Biopharmaceuticals administered to the human body have the potential to trigger the production of anti-drug (also called anti-therapeutic) antibodies (ADA) that can neutralize the therapeutic activity. For antibody therapeutics, cell-based neutralizing ADA assays are frequently used to evaluate ADA in clinical studies. We developed a method to detect neutralizing antibodies against MEDI-575, a fully human IgG2κ antagonistic antibody against PDGFR-α. We evaluated three assay formats, two of which measured late responses, cell proliferation and apoptosis, whereas the third assay detected an early signaling event, phosphorylation of PDGFR-α. Measuring phosphorylation provided a superior assay window and therefore was developed as a neutralizing ADA (NAb) assay. Matrix interference, however, was significant, and could be identified to be caused by PDGF-AA and PDGF-AB, apparently the two most abundant ligands of PDGFR-α present in human serum samples. A simple pre-treatment step, addition of an inhibitory antibody to PDGF-A, a subunit present in PDGF-AA and PDGF-AB, was found to eliminate matrix interference, increasing assay reliability and sensitivity. We integrated the pre-treatment step into assay development and qualified a robust NAb assay.

Comparison of two direct neutralizing assay formats using recombinant follicle-stimulating hormone as agonist

Characterizing anti-drug antibodies for neutralizing activity is commonly part of the immunogenicity testing package for most therapeutic proteins. Cell-based neutralization assays can generally be categorized as direct- or indirect assays depending on whether they are associated with therapeutics with agonistic- or antagonistic properties. This paper's aim is a comparison of the two direct neutralization assay formats; the variable- and fixed concentration assay format, using recombinant follicle-stimulating hormone as drug agonist. Essential validation- and performance parameters, such as sample through-put, cut-point, precision, sensitivity and drug tolerance, were compared. The fixed concentration assay format offers superior sample through-put (40 versus 6 samples), precision (coefficient of variation of ≤14% versus 34%) and almost 6 times better sensitivity and is generally recommended as the better option particularly for quasi-quantitative assessments of neutralizing antibodies.