Hydrocortisone inhibition of wild-type and αD200Q nicotinic acetylcholine receptors

A review of fetal cell lines used during drug development: Focus on COVID-19 vaccines, transplant medications, and biologics

PURPOSE

The recent coronavirus disease 2019 (COVID-19) pandemic and vaccine mandates have increased the number of patient questions related to how fetal cell lines are used during drug development and final manufacturing. This article describes our literature search and review of COVID-19 vaccines, transplant medications, and biologics whose development included use of fetal cell lines.

SUMMARY

A detailed literature search was conducted to identify the common fetal cell lines used in COVID-19 vaccine development; the two most prevalent fetal cell lines identified were HEK-293 and PER.C6. Subsequent literatures searches were conducted to identify transplant medications and biologics whose development included use of the HEK-293 or PER.C6 cell lines. For the COVID-19 vaccines, only the viral vector vaccine by Janssen was found to contain proteins produced by PER.C6 in the final preparation administered to patients, and Novavax is the only vaccine for which fetal cell lines were not directly involved in any portion of drug development. For transplant medications, many medications were studied in fetal cell lines in postmarketing studies after Food and Drug Administration approval; however, none of these medications contained fetal cells or would expose a patient to a fetal cell line. Many new biologics and cellular therapies for genetic diseases and malignancies have been directly developed from HEK-293 fetal cells or contain proteins produced directly from fetal cell lines.

CONCLUSION

There were very few drugs reviewed that were found to contain HEK-293 or PER.C6 fetal cells or proteins derived directly from fetal cell lines; however, use of fetal cell lines in biologics and gene therapies will continue to increase. Healthcare providers should be mindful of patients' beliefs while also correcting common misconceptions about how these fetal cell lines are used throughout drug development and manufacturing.

Functional Characteristics of the Nav1.1 p.Arg1596Cys Mutation Associated with Varying Severity of Epilepsy Phenotypes

Mutations of the SCN1A gene, which encodes the voltage-dependent Na+ channel's α subunit, are associated with diverse epileptic syndromes ranging in severity, even intra-family, from febrile seizures to epileptic encephalopathy. The underlying cause of this variability is unknown, suggesting the involvement of additional factors. The aim of our study was to describe the properties of mutated channels and investigate genetic causes for clinical syndromes' variability in the family of five SCN1A gene p.Arg1596Cys mutation carriers. The analysis of additional genetic factors influencing SCN1A-associated phenotypes was conducted through exome sequencing (WES). To assess the impact of mutations, we used patch clamp analysis of mutated channels expressed in HEK cells and in vivo neural excitability studies (NESs). In cells expressing the mutant channel, sodium currents were reduced. NESs indicated increased excitability of peripheral motor neurons in mutation carriers. WES showed the absence of non-SCA1 pathogenic variants that could be causative of disease in the family. Variants of uncertain significance in three genes, as potential modifiers of the most severe phenotype, were identified. The p.Arg1596Cys substitution inhibits channel function, affecting steady-state inactivation kinetics. Its clinical manifestations involve not only epileptic symptoms but also increased excitability of peripheral motor fibers. The role of Nav1.1 in excitatory neurons cannot be ruled out as a significant factor of the clinical phenotype.

Activity of TREK-2-like Channels in the Pyramidal Neurons of Rat Medial Prefrontal Cortex Depends on Cytoplasmic Calcium

Simple Summary

The pyramidal neurons of rat prefrontal cortex express potassium channels identified as a non-canonical splice variant of the TREK-2 channel. The main function of TREK channels is to regulate the resting membrane potential. We showed that cytoplasmic Ca²⁺ upregulates the activity of TREK-2-like channels. Previous studies have indicated that the activation of TREK-2 channels is mediated by PI(4,5)P2, a polyanionic lipid in the inner leaflet of the plasma membrane. While TREK channels are believed to not be regulated by calcium, our work shows otherwise. We propose a model in which calcium ions enable the formation of PI(4,5)P2 nanoclusters, which stabilize active conformation of the channel.

Abstract

TREK-2-like channels in the pyramidal neurons of rat prefrontal cortex are characterized by a wide range of spontaneous activity—from very low to very high—independent of the membrane potential and the stimuli that are known to activate TREK-2 channels, such as temperature or membrane stretching. The aim of this study was to discover what factors are involved in high levels of TREK-2-like channel activity in these cells. Our research focused on the PI(4,5)P2-dependent mechanism of channel activity. Single-channel patch clamp recordings were performed on freshly dissociated pyramidal neurons of rat prefrontal cortexes in both the cell-attached and inside-out configurations. To evaluate the role of endogenous stimulants, the activity of the channels was recorded in the presence of a PI(4,5)P2 analogue (PI(4,5)P2DiC8) and Ca²⁺. Our research revealed that calcium ions are an important factor affecting TREK-2-like channel activity and kinetics. The observation that calcium participates in the activation of TREK-2-like channels is a new finding. We showed that PI(4,5)P2-dependent TREK-2 activity occurs when the conditions for PI(4,5)P2/Ca²⁺ nanocluster formation are met. We present a possible model explaining the mechanism of calcium action.

Remission of myasthenia gravis following cervical adjustment

Myasthenia gravis (MG) is an autoimmune disorder, caused by circulating antibodies against the acetylcholine receptor (AChR) and associated proteins. Anticholinesterase medications and immunomodulating therapies are the mainstays of current treatment. Presented here is a case of a 51-year-old female who had been diagnosed with MG based on symptoms and continued elevation of antibody to AChR (anti-AChR) by her family physician. The patient's anticholinesterase medication was halted due to significant side effects affecting bowel function. She only received acupuncture treatment in the past 4 months prior to this presentation. Myasthenic symptoms deteriorated and the anti-AChR titer kept elevating after stopping medication. She originally came to us due to neck and back pain rather than myasthenic complaints. This case is interesting that her back pain and myasthenic symptoms went into complete remission within 1 month of initiating chiropractic adjustment. The concomitant recession of the myasthenic symptoms raises considerable interest for the mystery of MG, including the causal link between stress and autoimmune disease, the role of ACh in immune regulation, and the possible mechanisms of disease amelioration. Further studies would shed more light on the efficacy of various modalities in treating MG.