Aims and Scope Eurasian Journal of Medicine (Eurasian J Med) is an international, scientific, open access periodical published by independent, unbiased, and tripleblinded peer-review principles. The journal is the official publication of

RÉSUMÉ: La D-sérine en neurobiologie : neurotransmission et neuromodulation dans le SNC. l'homochiralité est fondamentale à la vie. Chez les organismes vivants, seuls les acides aminés lévogyres sont utilisés comme substrats pour la polymérisation et la formation de peptides et de protéines. Cependant, des acides aminés dextrogyres ont été détectés récemment dans différents organismes vivants dont des mammifères. parmi ces acides daminés, la d-sérine a été la plus étudiés. la d-sérine jouerait un rôle important comme neurotransmetteur dans le système nerveux central (SnC) chez l'humain en se liant au récepteur de la n-méthyl-d-aspartate (nMdar). la d-sérine se lie avec une haute affinité à un site co-agoniste du nMdar et, avec le glutamate, sert de médiateur dans plusieurs processus physiologiques et pathologiques vitaux dont la transmission nMdar, la plasticité synaptique et la neurotoxicité. C'est pourquoi on pense que la d-sérine jouerait un rôle clé comme déterminant de la neurotransmission médiée par nMdar dans le SnC des mammifères. dans ce contexte, nous revoyons les fonctions connues de la d-sérine en physiologie humaine, telles le développement du SnC et certaines pathologies comme les maladies neuropsychiatriques et neurodégénératives en lien avec une dysfonction de nMdar.

Unquestionably, polymers have influenced the world over the past 100 years. They are now more crucial than ever since the COVID-19 pandemic outbreak. The pandemic paved the way for certain polymers to be in the spotlight, namely sequencedefined polymers such as messenger ribonucleic acid (mRNA), which was the first type of vaccine to be authorized in the U.S. and Europe to protect against the SARS-CoV-2 virus. This rise of mRNA will probably influence scientific research concerning nucleic acids in general and RNA therapeutics in specific. In this Perspective, we highlight the recent trends in sequence-controlled and sequence-defined polymers. Then we discuss mRNA vaccines as an example to illustrate the need of ultimate sequence control to achieve complex functions such as specific activation of the immune system. We briefly present how mRNA vaccines are produced, the importance of modified nucleotides, the characteristic features, and the advantages and challenges associated with this class of vaccines. Finally, we discuss the chances and opportunities for polymer chemistry to provide solutions and contribute to the future progress of RNA-based therapeutics. We highlight two particular roles of polymers in this context. One represents conjugation of polymers to nucleic acids to form biohybrids. The other is concerned with advanced polymer-based carrier systems for nucleic acids. We believe that polymers can help to address present problems of RNA-based therapeutic technologies and impact the field beyond the COVID-19 pandemic.

Herein, we present a DNA circuit programmed for the delivery of CpG oligodeoxynucleotides (CpG ODNs) with the pharmacological immunostimulation function. The circuit employs a complementary DNA (cDNA) strand to deactivate the biological function of CpG ODNs via hybridization, while T7 exonuclease mediates the activation by hydrolyzing the cDNA and releasing the CpG ODN as an active moiety. We investigated the influence of several factors on the kinetic profile and temporal behavior of the circuit. These include the design of the cDNA strand, the concentration of the DNA duplex, and the concentration of T7 exonuclease. The DNA circuit's in vitro activation resulted in toll-like receptor 9 stimulation in the HEK-engineered cell line, as well as tumor necrosis factor-alpha release by J774A.1 macrophages. By programming the DNA circuit to control the release of the CpG ODN, we achieved an altered pharmacological profile with acute and potent immunostimulation, in comparison to a system without controlled CpG ODN release, which exhibited a slow and delayed response. Our findings demonstrate the potential of DNA circuits in controlling the pharmacological activity of DNA strands for controlled drug delivery.