Cell chirality: its origin and roles in left-right asymmetric development

Lactate-depleted pillar[5]arene-based chiral supramolecular nanovesicles for L-glucose-mediated tumor-specific chemodynamic- and photodynamic-synergistic therapy

The distinct interactions of D/L-glucose with cells and biological systems have garnered significant attention. However, the impact of chiral glucose-modified nanomaterials on cancer diagnosis and treatment remains largely unexplored. Here, based on the host-guest interaction between D-/L-glucose-modified pillar[5]arene (D-/L-CP5) serving as the host molecule and Fe-porphyrin derivatives (FeTPPNHC) acting as the guest, an acid-responsive chiral supramolecular vesicle was constructed for transporting lactate oxidases (LOx) (denoted as LOx@D-/L-CP5⊃FeTPPNHC), aiming to enhance chirality-mediated tumor-specific cascade chemodynamic therapy (CDT) and photodynamic therapy (PDT) through the depletion of lactic acid (LA). Surprisingly, the L-glucose-mediated chiral vesicles exhibit remarkable chirality recognition and lactate depletion capabilities, which were higher than the D-glucose-mediated chiral vesicles. Once internalized by cancer cells, L-supramolecular nanomicelles can directly consume LA to generate a considerable amount of H2O2, which can then be converted into ˙OH and 1O2. In vitro and in vivo studies demonstrate the high tumor specificity and therapeutic efficacy of LOx@LCP5⊃FeTPPNHC. The findings suggest that chiral glucose-modified nanomaterials hold great potential in targeted cancer treatment, paving the way for the development of innovative cancer therapeutics based on their unique interactions with biological systems.

Chirality Quantification for High-Performance Nanophotonic Biosensors

Recent advancements in chiral metabolomics have facilitated the discovery of disease biomarkers through the enantioselective measurement of metabolites, offering new opportunities for diagnosis, prognosis, and personalized medicine. Although chiral photonic nanomaterials have emerged as promising platforms for chiral biosensing, enhancing sensitivity and enabling the detection of biomolecules at extremely low concentrations, a deeper understanding of the relationship between structural and optical chirality is crucial for optimizing these platforms. This perspective examines recent methods for quantifying chirality, including the Hausdorff Chirality Measure (HCM), Continuous Chirality Measure (CCM), Osipov-Pickup-Dunmur (OPD), and Graph-Theoretical Chirality (GTC) measure. These approaches have advanced the understanding of chirality in both materials and biomolecules, as well as its correlation with optical responses. This work emphasizes the role of chiral quantification in improving biosensor performance and explores the potential of near-field chiroptical studies to enhance sensor capabilities. Finally, this work addresses key challenges and outline future research directions for advancing chiral biosensors, with a focus on improving nano-bio interface interactions to drive the development of next-generation sensing technologies.

Chiral polymer-induced hydroxyapatite for promoting bone regeneration

Chirality is one of the basic characteristics of living matter, yet the effect of chiral polymers on osteogenesis is seldom studied. Thus, it is necessary to deeply recognize the behaviors of chiral polymers in osteogenic processes, which can be beneficial for the development of bone repair materials. In this work, chiral hydroxyapatite (HAP) was constructed simply using poly(levorotatory/dextral-tartaric acid) as the guest of the chiral transfer system. We studied the influence of chiral HAPs on the migration and differentiation of pre-osteoblasts, and angiogenesis of endothelial cell in vitro. The results showed that poly(levorotatory-tartaric acid)-induced HAP did promote vascular remodeling and exhibited excellent impact on osteogenetic differentiation by improving the related gene and protein expression, whereas no significant change was observed in poly(dextral-tartaric acid) or poly(racemic-tartaric acid) induced HAP, respectively. This study highlighted the effects of chiral polymers on osteogenic potential, which laid the groundwork for the development of biomaterials for bone regeneration.

From barbiturates to ganaxolone: The importance of chirality in drug development and in understanding the actions of old and new antiseizure medications

Out of 37 antiseizure medications (ASMs) currently in the market, 17 are chiral molecules and an additional one (oxcarbazepine) is a prodrug of the chiral compound licarbazepine. Of the 17 chiral ASMs, six (ethosuximide, fenfluramine, methsuximide, mephobarbital, stiripentol and vigabatrin) are marketed as racemates, and the remainder are licensed as enantiomerically pure medicines. Of note, all chiral ASMs introduced prior to 1990 were marketed as racemates. Stiripentol, fenfluramine and vigabatrin are the only racemic ASMs approved by the FDA >10 years after the release of regulatory guidelines on the development of chiral medicines. Despite the fact that pharmacokinetic and pharmacodynamic differences between enantiomers have been recognized for decades, the importance of chirality in understanding the biological actions of ASMs is not widely appreciated, and many recent publications on racemic ASMs refer to these medications as if they were a single molecular entity. In the present article, we provide a critical review of chiral ASMs developed between the 1920s, when mephobarbital was introduced, and 2022, when the last chiral ASM (ganaxolone) was approved. We summarize available data on stereoselective differences in pharmacokinetics and pharmacodynamics of ASMs marketed as racemates. We also discuss regulatory aspects related to the introduction of racemic medicines within the current regulatory scenario in Europe and the U.S., focusing on stiripentol, vigabatrin and fenfluramine as examples of different approaches. We identified a number of critical knowledge gaps that are relevant to the use of chiral drugs in epilepsy, including a remarkable lack of published information on the comparative pharmacokinetics, toxicity and antiseizure activity of the enantiomers of most racemic ASMs. The importance of chirality aspects in understanding the clinical actions of racemic ASMs is discussed, together with the rationale for the development of enantiomerically pure follow-up compounds with potentially improved efficacy, safety and commercial viability.

Bilateral cellular flows display asymmetry prior to left-right organizer formation in amniote gastrulation

A bilateral body plan is predominant throughout the animal kingdom. Bilaterality of amniote embryos becomes recognizable as midline morphogenesis begins at gastrulation, bisecting an embryonic field into the left and right sides, and left-right (LR) asymmetry patterning follows. While a series of laterality genes expressed after the LR compartmentalization has been extensively studied, the laterality patterning prior to and at the initiation of midline morphogenesis has remained unclear. Here, through a biophysical quantification in a high spatial and temporal resolution, applied to a chick model system, we show that a large-scale bilateral counterrotating cellular flow, termed "polonaise movements", display LR asymmetries in early gastrulation. This cell movement starts prior to the formation of the primitive streak (PS) (the earliest midline structure) and the subsequent appearance of Hensen's node (the LR organizer). The cellular flow speed and vorticity unravel the location and timing of the LR asymmetries. The bilateral flows displayed a Right dominance after 6 h since the start of cell movements. Mitotic arrest that diminishes PS formation resulted in changes in the bilateral flow pattern, but the Right dominance persisted. Our data indicate that the LR asymmetry in amniote gastrula becomes detectable earlier than suggested by current models, which assume that the asymmetric regulation of the laterality signals at the node leads to the LR patterning. More broadly, our results suggest that physical processes can play an unexpected but significant role in influencing LR laterality during embryonic development.

Exploring the Crystal Landscape of Mandelamide and Chiral Resolution via Cocrystallization

The crystal structures of (±)-mandelamide, S-mandelamide, and enantioenriched mandelamide (94 S : 6 R) were determined. Diastereomeric cocrystal pairs of S-mandelamide with both enantiomers of mandelic acid and proline were synthesized. The diastereomeric cocrystal pairs of S-mandelamide with S/R-mandelic acid form 1:1 cocrystals in each case, while the diastereomeric cocrystal pairs of S-mandelamide with proline have different stoichiometries. Preliminary investigation of this diastereomeric cocrystal system for chiral resolution shows promise.

Large-scale genetic mapping for human brain asymmetry

Left-right asymmetry is an important aspect of human brain organization for functions including language and hand motor control, which can be altered in some psychiatric traits. The last 5 years have seen rapid advances in the identification of specific genes linked to variation in asymmetry of the human brain and/or handedness. These advances have been driven by a new generation of large-scale genome-wide association studies, carried out in samples ranging from roughly 16,000 to over 1.5 million participants. The implicated genes tend to be most active in the embryonic and fetal brain, consistent with early developmental patterning of brain asymmetry. Several of the genes encode components of microtubules or other microtubule-associated proteins. Microtubules are key elements of the internal cellular skeleton (cytoskeleton). A major challenge remains to understand how these genes affect, or even induce, the brain's left-right axis. Several of the implicated genes have also been associated with psychiatric or neurologic disorders, and polygenic dispositions to autism and schizophrenia have been associated with structural brain asymmetry. Knowledge of developmental mechanisms that lead to hemispheric specialization may ultimately help to define etiologic subtypes of brain disorders.

Homochirality in the Vicsek model: Fluctuations and potential implications for cellular flocks

Chirality is a feature of many biological systems, and much research has been focused on understanding the origin and implications of this property. Famously, sugars and amino acids found in nature are homochiral, i.e., chiral symmetry is broken and only one of the two possible chiral states is ever observed. Certain types of cells show chiral behavior, too. Understanding the origin of cellular chirality and its effect on tissues and cellular dynamics is still an open problem and subject to much (recent) research, e.g., in the context of drosophila morphogenesis. Here, we develop a simple model to describe the possible origin of homochirality in cells. Combining the Vicsek model for collective behavior with the model of Jafarpour et al. [Phys. Rev. Lett. 115, 158101 (2015)0031-900710.1103/PhysRevLett.115.158101], developed to describe the emergence of molecular homochirality, we investigate how a homochiral state might have evolved in cells from an initially symmetric state without any mechanisms that explicitly break chiral symmetry. We investigate the transition to homochirality and show how the "openness" of the system as well as noise determine if and when a globally homochiral state is reached. While hypothetical and explorative in nature, our analysis may serve as a starting point for more realistic models of chirality in flocking multicellular systems.

Fatigue Analysis of Axisymmetric Chiral Cellular Structures Made out of 316L Stainless Steel

In the proposed study, the fatigue analysis of an axisymmetric chiral cellular structure and its modified form, made of stainless steel 316L, is carried out. The main goal of the original structure geometry was to absorb as much mechanical energy as possible with its auxetic behaviour. However, it was found through testing that its response could be improved by modifying the thickness of the struts through the structure. Representative models for the original and modified geometries were generated using a script adapted for this numerical simulation. Three different types of displacement in the shape of sine waves were used to load the structures. A hexagonal mesh was assigned and determined by convergence analysis. An existing material model with the necessary LCF parameters was assigned in the computational analyses. The data from multiple simulations were recorded and presented in graphs that showed how the fatigue life of the structures changed depending on the level of strain. We also analysed stresses and plastic deformations that occur in the structures. The results showed that, despite a better stress distribution, the fatigue life of the optimised structure was shorter in all cases.

Structure-based protein and small molecule generation using EGNN and diffusion models: A comprehensive review

Recent breakthroughs in deep learning have revolutionized protein sequence and structure prediction. These advancements are built on decades of protein design efforts, and are overcoming traditional time and cost limitations. Diffusion models, at the forefront of these innovations, significantly enhance design efficiency by automating knowledge acquisition. In the field of de novo protein design, the goal is to create entirely novel proteins with predetermined structures. Given the arbitrary positions of proteins in 3-D space, graph representations and their properties are widely used in protein generation studies. A critical requirement in protein modelling is maintaining spatial relationships under transformations (rotations, translations, and reflections). This property, known as equivariance, ensures that predicted protein characteristics adapt seamlessly to changes in orientation or position. Equivariant graph neural networks offer a solution to this challenge. By incorporating equivariant graph neural networks to learn the score of the probability density function in diffusion models, one can generate proteins with robust 3-D structural representations. This review examines the latest deep learning advancements, specifically focusing on frameworks that combine diffusion models with equivariant graph neural networks for protein generation.

Synthesis, Crystal Structures, Antimicrobial Activity, and Acute Toxicity Evaluation of Chiral Zn(II) Schiff Base Complexes

Four mononuclear bioefficient zinc coordination complexes [Zn(NN)3](ClO4)2 (A-D) involving chiral bidentate Schiff base ligands have been synthesized and characterized by IR, 1H, and 13C NMR spectroscopy and mass spectrometry. X-ray crystal structures of three of the zinc complexes revealed that the zinc metal ion is hexacoordinated, exhibiting a distorted octahedral geometry where both the nitrogen atoms (NN = pyridyl and imine) of imines are coordinated to the central zinc ion. The isolated zinc complexes were evaluated for their antimicrobial activity in vitro against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus, displaying varying levels of growth inhibition. An acute toxicity test conducted using Artemia salina and Swiss albino mice showed that the zinc complexes A-D were non-toxic towards A. salina at concentrations below 414, 564, 350, and 385 µM, respectively, and did not affect liver biochemical parameters, although pyknosis was induced in hepatocytes of the treated mice.

Distinct cellular and junctional dynamics independently regulate the rotation and elongation of the embryonic gut in Drosophila

Complex organ structures are formed with high reproducibility. To achieve such intricate morphologies, the responsible epithelium undergoes multiple simultaneous shape changes, such as elongation and folding. However, these changes have typically been assessed separately. In this study, we revealed how distinct shape changes are controlled during internal organ morphogenesis. The Drosophila embryonic hindgut undergoes left-right asymmetric rotation and anteroposterior elongation in a tissue-autonomous manner driven by cell sliding and convergent extension, respectively, in the hindgut epithelia. However, the regulation of these processes remains unclear. Through genetic analysis and live imaging, we demonstrated that cell sliding and convergent extension are independently regulated by Myosin1D and E-cadherin, and Par-3, respectively, whereas both require MyosinII activity. Using a mathematical model, we demonstrated that independently regulated cellular dynamics can simultaneously cause shape changes in a single mechanical system using anisotropic edge contraction. Our findings indicate that distinct cellular dynamics sharing a common apparatus can be independently and simultaneously controlled to form complex organ shapes. This suggests that such a mechanism may be a general strategy during complex tissue morphogenesis.

Proton Conduction in Chiral Molecular Assemblies of Azolium-Camphorsulfonate Salts

Chiral molecular assemblies have attracted considerable attention because of their interesting physical properties, such as spin-selective electron transport. Cation-anion salts of three azolium cations, imidazolium (HIm+), triazolium (HTrz+), and thiazolium (HThz+), in combination with a chiral camphorsulfonate (1S-CS-) and their racemic compounds (rac-CS-) were prepared and compared in terms of phase transitions, crystal structures, dynamics of constituent molecules, dielectric responses, and proton conductivities. The cation-anion crystals containing HIm+ showed no significant difference in proton conductivity between the homochiral and racemic crystals, whereas the HTrz+-containing crystals showed higher proton conductivity and lower activation energy in the homochiral form than in the racemic form. A two-dimensional hydrogen-bonding network consisting of HTrz+ and -SO3- groups and similar in-plane rotational motion was observed in both crystals; however, the HTrz+ cation in the homochiral crystal exhibited the rotational motion modulated with translational motion, whereas the HTrz+ cation in the racemic crystal exhibited almost steady in-plane rotational motion. The different motional degrees of freedom were confirmed by crystal structure analyses and temperature- and frequency-dependent dielectric constants. In contrast, steady in-plane rotational motion with the thermally activated fluctuating motion of CS- was observed both in homochiral and racemic crystals containing HIm+, which averaged the motional space of protons resulting in similar dielectric responses and proton conductivities. The control of motional degrees of freedom in homochiral crystals affects the proton conductivity and is useful for the design of molecular proton conductors.

Circular dichroism of relativistically-moving chiral molecules

Understanding the impact of the relativistic motion of a chiral molecule on its optical response is a prime challenge for fundamental science, but it also has a direct practical relevance in our search for extraterrestrial life. To contribute to these significant developments, we describe a multi-scale computational framework that combines quantum chemistry calculations and full-wave optical simulations to predict the chiral optical response from molecules moving at relativistic speeds. Specifically, the effect of a relativistic motion on the transmission circular dichroism (TCD) of three life-essential biomolecules, namely, B-DNA, chlorophyll a, and chlorophyll b, is investigated. Inspired by previous experiments to detect interstellar chiral molecules, we assume that the molecules move between a stationary observer and a light source, and we study the rotationally averaged TCD as a function of the speed of the molecule.We find that the TCD spectrum that contains the signatures of the molecules shifts with increasing speed to shorter wavelengths, with the effects already being visible for moderate velocities.

Handedness in Animals and Plants

Structural and functional asymmetries are traceable in every form of life, and some lateralities are homologous. Functionally speaking, the division of labour between the two halves of the brain is a basic characteristic of the nervous system that arose even before the appearance of vertebrates. The most well-known expression of this specialisation in humans is hand dominance, also known as handedness. Even if hand/limb/paw dominance is far more commonly associated with the presence of a nervous system, it is also observed in its own form in aneural organisms, such as plants. To date, little is known regarding the possible functional significance of this dominance in plants, and many questions remain open (among them, whether it reflects a generalised behavioural asymmetry). Here, we propose a comparative approach to the study of handedness, including plants, by taking advantage of the experimental models and paradigms already used to study laterality in humans and various animal species. By taking this approach, we aim to enrich our knowledge of the concept of handedness across natural kingdoms.

Stereochemically-aware bioactivity descriptors for uncharacterized chemical compounds

Stereochemistry plays a fundamental role in pharmacology. Here, we systematically investigate the relationship between stereoisomerism and bioactivity on over 1 M compounds, finding that a very significant fraction (~ 40%) of spatial isomer pairs show, to some extent, distinct bioactivities. We then use the 3D representation of these molecules to train a collection of deep neural networks (Signaturizers3D) to generate bioactivity descriptors associated to small molecules, that capture their effects at increasing levels of biological complexity (i.e. from protein targets to clinical outcomes). Further, we assess the ability of the descriptors to distinguish between stereoisomers and to recapitulate their different target binding profiles. Overall, we show how these new stereochemically-aware descriptors provide an even more faithful description of complex small molecule bioactivity properties, capturing key differences in the activity of stereoisomers.Scientific contributionWe systematically assess the relationship between stereoisomerism and bioactivity on a large scale, focusing on compound-target binding events, and use our findings to train novel deep learning models to generate stereochemically-aware bioactivity signatures for any compound of interest.

Left-right Myosin-Is, Myosin1C, and Myosin1D exhibit distinct single molecule behaviors on the plasma membrane of Drosophila macrophages

Left-right (LR) asymmetry is crucial for animal development, particularly in Drosophila where LR-asymmetric morphogenesis of organs hinges on cellular-level chirality, termed cell chirality. In this species, two class I myosins, Myosin1D (Myo1D), and Myosin1C (Myo1C), respectively determine dextral (wild type) and sinistral (mirror image) cell chirality. Previous studies demonstrated Myo1D's ability to propel F-actin in leftward circles during in vitro gliding assays, suggesting its mechanochemical role in defining dextral chirality. Conversely, Myo1C propels F-actin without exhibiting LR-directional preference in this assay, suggesting at other properties governing sinistral chirality. Given the interaction of Myo1D and Myo1C with the membrane, we hypothesized that differences in their membrane behaviors might be critical in dictating their dextral or sinistral activities. In this study, employing single-molecule imaging analyses, we investigated the dynamic behaviors of Myo1D and Myo1C on the plasma membrane. Our findings revealed that Myo1C exhibits a significantly greater proportion of slow-diffusing population compared to Myo1D. Importantly, this characteristic was contingent upon both head and tail domains of Myo1C. The distinct diffusion patterns of Myo1D and Myo1C did not exert mutual influence on each other. This divergence in membrane diffusion between Myo1D and Myo1C may be crucial for dictating cell and organ chirality.

Differences in enantiomeric diffusion can lead to selective chiral amplification

A fundamental question associated with chirality is how mixtures containing equal amounts of interconverting enantiomers can spontaneously convert to systems enriched in only one of them. Enantiomers typically have similar chemical properties, but can exhibit distinct reactivity under specific conditions, and these differences can be used to bias the system's composition in favor of one enantiomer. Transport properties are also expected to differ for enantiomers in chiral solvents, but the role of such differences in chiral symmetry breaking has not been clarified yet. In this work, we develop a theoretical framework to show that asymmetry in diffusion properties can trigger a spontaneous and selective symmetry breaking in mixtures of enantiomers. We derive a generic evolution equation for the enantiomeric excess in a chiral solvent. This equation shows that the relative stability of homochiral domains is dictated by the difference of diffusion coefficients of the two enantiomers. Consequently, deracemization toward a specific enantiomeric excess can be achieved when this difference is large enough. These results hold significant implications for our understanding of chiral symmetry breaking.

Exome-wide analysis implicates rare protein-altering variants in human handedness

Handedness is a manifestation of brain hemispheric specialization. Left-handedness occurs at increased rates in neurodevelopmental disorders. Genome-wide association studies have identified common genetic effects on handedness or brain asymmetry, which mostly involve variants outside protein-coding regions and may affect gene expression. Implicated genes include several that encode tubulins (microtubule components) or microtubule-associated proteins. Here we examine whether left-handedness is also influenced by rare coding variants (frequencies ≤ 1%), using exome data from 38,043 left-handed and 313,271 right-handed individuals from the UK Biobank. The beta-tubulin gene TUBB4B shows exome-wide significant association, with a rate of rare coding variants 2.7 times higher in left-handers than right-handers. The TUBB4B variants are mostly heterozygous missense changes, but include two frameshifts found only in left-handers. Other TUBB4B variants have been linked to sensorineural and/or ciliopathic disorders, but not the variants found here. Among genes previously implicated in autism or schizophrenia by exome screening, DSCAM and FOXP1 show evidence for rare coding variant association with left-handedness. The exome-wide heritability of left-handedness due to rare coding variants was 0.91%. This study reveals a role for rare, protein-altering variants in left-handedness, providing further evidence for the involvement of microtubules and disorder-relevant genes.

Flavonostilbenes natural hybrids from Rhamnoneuron balansae as potential antitumors targeting ALDH1A1: molecular docking, ADMET, MM-GBSA calculations and molecular dynamics studies

Several studies have linked Cancer stem cells (CSCs) to cancer resistance development to chemotherapy and radiotherapy. ALDH1A1 is a key enzyme that regulates the gene expression of CSCs and creates an immunosuppressive tumor microenvironment. It was reported that quercetin and resveratrol were among the inhibitors of ALDH1A1. In early 2022, it was reported that new 11 flavonostilbenes (rhamnoneuronal D-N) were isolated from Rhamnoneuron balansae as potential antiaging natural products. Rhamnoneuronal H (5) could be envisioned as a natural hybrid of quercetin and resveratrol. It was therefore hypothesized that 5 and its analogous isolates rhamnoneuronal D-G (1-4) and rhamnoneuronal I-N (6-11) would have potential ALDH1A1 inhibitory activity. To this end, all isolates were subjected to molecular docking, MM-GBSA, ADMET, and molecular dynamics simulations studies to assess their potential as new leads for cancer treatment targeting ALDH1A1. In silico findings revealed that natural hybrid 5 has a similar binding affinity, judged by MM-GBSA, to the ALDH1A1 active site when compared to the co-crystalized ligand (-64.71 kcal/mole and -64.12 kcal/mole, respectively). Despite having lesser affinity than that of the co-crystalized ligand, the rest of the flavonostilbenes, except 2-4, displayed better binding affinities (-37.55 kcal/mole to -58.6 kcal/mole) in comparison to either resveratrol (-34.44 kcal/mole) or quercetin (-36.48 kcal/mole). Molecular dynamic simulations showed that the natural hybrids 1, 5-11 are of satisfactory stability up to 100 ns. ADMET outcomes indicate that these hybrids displayed acceptable properties and hence could represent an ideal starting point for the development of potent ALDH1A1 inhibitors for cancer treatment.Communicated by Ramaswamy H. Sarma.

Helical motors and formins synergize to compact chiral filopodial bundles: A theoretical perspective

Chiral actin bundles have been shown to play an important role in cell dynamics, but our understanding of the molecular mechanisms which combine to generate chirality remains incomplete. To address this, we numerically simulate a crosslinked filopodial bundle under the actions of helical myosin motors and/or formins and examine the collective buckling and twisting of the actin bundle. We first show that a number of proposed mechanisms to buckle polymerizing actin bundles without motor activity fail under biologically-realistic parameters. We then demonstrate that a simplified model of myosin spinning action at the bundle base effectively "braids" the bundle, but cannot control compaction at the fiber tips. Finally, we show that formin-mediated polymerization and motor activity can act synergitically to compact filopodium bundles, as motor activity bends filaments into shapes that activate twist forces induced by formins. Stochastic fluctuations of actin polymerization rates and slower cross linking dynamics both increase buckling and decrease compaction. We discuss implications of our findings for mechanisms of cytoskeletal chirality.

Helical vasculogenesis driven by cell chirality

The cellular helical structure is well known for its crucial role in development and disease. Nevertheless, the underlying mechanism governing this phenomenon remains largely unexplored, particularly in recapitulating it in well-controlled engineering systems. Leveraging advanced microfluidics, we present compelling evidence of the spontaneous emergence of helical endothelial tubes exhibiting robust right-handedness governed by inherent cell chirality. To strengthen our findings, we identify a consistent bias toward the same chirality in mouse vascular tissues. Manipulating endothelial cell chirality using small-molecule drugs produces a dose-dependent reversal of the handedness in engineered vessels, accompanied by non-monotonic changes in vascular permeability. Moreover, our three-dimensional cell vertex model provides biomechanical insights into the chiral morphogenesis process, highlighting the role of cellular torque and tissue fluidity in its regulation. Our study unravels an intriguing mechanism underlying vascular chiral morphogenesis, shedding light on the broader implications and distinctive perspectives of tubulogenesis within biological systems.

Chiral nanomaterial-based approaches for diagnosis and treatment of protein-aggregated neurodiseases: current status and future opportunities

Protein misfolding and its aggregation, known as amyloid aggregates (Aβ), are some of the major causes of more than 20 diseases such as Parkinson's disease, Alzheimer's disease, and type 2 diabetes. The process of Aβ formation involves an energy-driven oligomerization of Aβ monomers, leading to polymerization and eventual aggregation into fibrils. Aβ fibrils exhibit multilevel chirality arising from its amino acid residues and the arrangement of folded polypeptide chains; thus, a chirality-driven approach can be utilized for the detection and inhibition of Aβ fibrils. In this regard, chiral nanomaterials have recently opened new possibilities for various biomedical applications owing to their stereoselective interaction with biological systems. Leveraging this chirality-driven approach with chiral nanomaterials against protein-aggregated diseases could yield promising results, particularly in the early detection of Aβ forms and the inhibition of Aβ aggregate formation via specific and strong "chiral-chiral interaction." Despite the advantages, the development of advanced theranostic systems using chiral nanomaterials against protein-aggregated diseases has received limited attention so far because of considerably limited formulations for chiral nanomaterials and lack of information of their chiroptical behavior. This review aims to present the current status of chiral nanomaterials explored for detecting and inhibiting Aβ forms. This review covers the origin of chirality in amyloid fibrils and nanomaterials and different chiral detection methods; furthermore, different chiral nanosystems such as chiral plasmonic nanomaterials, chiral carbon-based nanomaterials, and chiral nanosurfaces, which have been used so far for different therapeutic applications against protein-aggregated diseases, are discussed in detail. The findings from this review may pave the way for the development of novel approaches using chiral nanomaterials to combat diseases resulting from protein misfolding and can further be extended to other disease forms.

Chiral plasmonic sensing: From the perspective of light-matter interaction

Molecular chirality is represented as broken mirror symmetry in the structural orientation of constituent atoms and plays a pivotal role at every scale of nature. Since the discovery of the chiroptic property of chiral molecules, the characterization of molecular chirality is important in the fields of biology, physics, and chemistry. Over the centuries, the field of optical chiral sensing was based on chiral light-matter interactions between chiral molecules and polarized light. Starting from simple optics-based sensing, the utilization of plasmonic materials that could control local chiral light-matter interactions by squeezing light into molecules successfully facilitated chiral sensing into noninvasive, ultrasensitive, and accurate detection. In this Review, the importance of plasmonic materials and their engineering in chiral sensing are discussed based on the principle of chiral light-matter interactions and the theory of optical chirality and chiral perturbation; thus, this Review can serve as a milestone for the proper design and utilization of plasmonic nanostructures for improved chiral sensing.

Advancement in chiral heterocycles for the antidiabetic activity

For the synthesis and development of pharmaceuticals, chirality is an important structural component. Chiral heterocyclic compounds have annoyed the interest of synthetic chemists who are working to create useful and efficient techniques for these molecules. As indicated by the expanding number of chiral drugs created in the last two decades, the link between chirality and pharmacological activity has become more important in the pharmaceutical and biopharmaceutical industries. Approximately 65% of currently used drugs are chiral, and many of them are promoted as racemates in many circumstances. There are a growing number of new chiral heterocyclic compounds with important biological properties and intriguing uses in medical chemistry and drug discovery. In this study, we review current breakthroughs in chiral heterocycles and their different physiological activities that have been published in the last year (from 2010 to early 2023). This study focuses on the current trends in the use of chiral heterocycles in drug design and the creation of several powerful and competent candidates for diabetic illnesses.

Flow-induced periodic chiral structures in an achiral nematic liquid crystal

Supramolecular chirality typically originates from either chiral molecular building blocks or external chiral stimuli. Generating chirality in achiral systems in the absence of a chiral input, however, is non-trivial and necessitates spontaneous mirror symmetry breaking. Achiral nematic lyotropic chromonic liquid crystals have been reported to break mirror symmetry under strong surface or geometric constraints. Here we describe a previously unrecognised mechanism for creating chiral structures by subjecting the material to a pressure-driven flow in a microfluidic cell. The chirality arises from a periodic double-twist configuration of the liquid crystal and manifests as a striking stripe pattern. We show that the mirror symmetry breaking is triggered at regions of flow-induced biaxial-splay configurations of the director field, which are unstable to small perturbations and evolve into lower energy structures. The simplicity of this unique pathway to mirror symmetry breaking can shed light on the requirements for forming macroscopic chiral structures.

Chirality-Selected Coacervate by Chiral Gemini Surfactant

Chiral surfactants present opportunities to self-assemble into supramolecules with a chiral trait; however, the effects of stereochemistry on the formation of simple coacervates remain unclear. Here, we investigate the chirality-selected phase behavior in mixtures of chiral gemini surfactant 1,4-bis(dodecyl-N,N-dimethylammonium bromide)-2,3-butanediol (12-4(OH)2-12) with an oppositely charged chiral mandelic acid (MA). It demonstrates that altering the chirality of surfactants yields a heightened ability to regulate the phase behavior, leading to the formation of three different network-like structures, i.e., wormlike micelle, coacervate, and hydrogel, in the racemate, enantiomer, and mesomer, respectively. The different aggregate structures arise from the intermolecular and intramolecular hydrogen-bond interactions of the two hydroxyl groups located at stereogenic centers. Intriguingly, although they contain similar microstructures, the solid-like hydrogel and liquid-like wormlike micelle show similar low hydration ability and have no encapsulation capability, whereas only coacervate formed by the enantiomers of 12-4(OH)2-12 displays liquid-like characteristics, strong capacity to sequester diverse solutes, and high affinity for tightly bound water simultaneously. These findings further highlight the unique and advantageous properties of coacervates as a promising model for exploring the biological process and understanding how chirality plays a crucial role in early life scenarios and cell evolution at the molecular level.

Chiral Mesostructured Inorganic Materials with Optical Chiral Response

Fabricating chiral inorganic materials and revealing their unique quantum confinement-determined optical chiral responses are crucial tasks in the multidisciplinary fields of chemistry, physics, and biology. The field of chiral mesostructured inorganic materials started from the synthesis of individual nanocrystals and evolved to include their assembly from metals, semiconductors, ceramics, and inorganic salts endowed with various chiral structures ranging from atomic to micron scales. This tutorial review highlights the recent research on chiral mesostructured inorganic materials, especially the novel expression of mesostructured chirality and endowed optical chiral response, and it may inspire us with new strategies for the design of chiral inorganic materials and new opportunities beyond the traditional applications of chirality. Fabrication methods for chiral mesostructured inorganic materials are classified according to chirality type, scale, and symmetry-breaking mechanism. Special attention is given to highlight systems with original discoveries, exceptional phenomena, or unique mechanisms of optical chiral response for left- and right-handedness.

Manipulation of Hierarchical Chiral Self-assembly and Anion Recognition by Supramolecular Systems of β-Glucopyranoside, Pillar[5]arenes, and Polyoxometalates

Hierarchical chiral structures have broad applications in optical devices, asymmetric catalysis, and biological systems. The delicate balance of various interactions are key to the self-assembly of chiral structures. Herein, a ternary co-assembly consisting of cationic pillar[5]arenes (P5As), anionic β-glucopyranoside (βGlcD/βGlcL), and Anderson-type polyoxometalates (POMs) were constructed. Through adjusting the stoichiometry of βGlcD, the assemblies were effectively controlled to form hierarchical nano-leaf assemblies with twisted nanoribbons in a homochiral direction. The co-assemblies exhibit strong Cotton effects, and successfully induced the chirality of Anderson-type POMs. More interestingly, by changing the central metal in Anderson-type POMs (XMo6 O24 3- (X=Cr, Al, and Ga)), even though the three clusters have the same numbers of charge and size, the hierarchical chirality of the related assemblies varied in the morphology of the assemblies and the Cotton effect in the CD spectra. Results in theoretical calculations and ITC titration indicates that the tiny difference in long-range electrostatic interaction would result in the anion recognition of POMs, modulated by βGlcD through host-guest inclusion and hydrogen bonding in the assembly process.

Enlightening dynamic functions in molecular systems by intrinsically chiral light-driven molecular motors

Chirality is a fundamental property which plays a major role in chemistry, physics, biological systems and materials science. Chiroptical artificial molecular motors (AMMs) are a class of molecules which can convert light energy input into mechanical work, and they hold great potential in the transformation from simple molecules to dynamic systems and responsive materials. Taking distinct advantages of the intrinsic chirality in these structures and the unique opportunity to modulate the chirality on demand, chiral AMMs have been designed for the development of light-responsive dynamic processes including switchable asymmetric catalysis, chiral self-assembly, stereoselective recognition, transmission of chirality, control of spin selectivity and biosystems as well as integration of unidirectional motion with specific mechanical functions. This review focuses on the recently developed strategies for chirality-led applications by the class of intrinsically chiral AMMs. Finally, some limitations in current design and challenges associated with recent systems are discussed and perspectives towards promising candidates for responsive and smart molecular systems and future applications are presented.

Advances in Enantiomer-Dependent Nanotherapeutics

The nanoscale properties of nanomaterials, especially nanoparticles, including size, shape, and surface charge, have been extensively studied for their impact on nanomedicine. Given the inherent chiral nature of biological systems and their high enantiomeric selectivity, there is rising interest to manipulate the chirality of nanomaterials to enhance their biomolecular interactions and improve nanotherapeutics. Chiral nanostructures are currently more prevalently used in biosensing and diagnostic applications owing to their distinctive physical and optical properties, but they hold great promise for use in nanomedicine. In this Review, we first discuss stereospecific interactions between chiral nanomaterials and biomolecules before comparing the synthesis and characterization methods of chiral nanoparticles and nanoassemblies. Finally, we examine the applications of chiral nanotherapeutics in cancer, immunomodulation, and neurodegenerative diseases and propose plausible mechanisms in which chiral nanomaterials interact with cells for biological manipulation. This Review on chirality is a timely reminder of the arsenal of nanoscale modifications to boost research in nanotherapeutics.

The Actin Crosslinker Fascin Regulates Cell Chirality

The left-right (L-R) asymmetry of the cells, or cell chirality, is a well-known intrinsic property derived from the dynamic organization of the actin cytoskeleton. Cell chirality can be regulated by actin-binding proteins such as α-actinin-1 and can also be mediated by certain signaling pathways, such as protein kinase C (PKC) signaling. Fascin, an actin crosslinker known to mediate parallel bundling of actin filaments, appears as a prominent candidate in cell chirality regulation, given its role in facilitating cell migration as an important PKC substrate. Here, it is shown that the chirality of NIH/3T3 cells can be altered by PKC activation and fascin manipulation. With either small-molecule drug inhibition or genetic knockdown of fascin, the chirality of 3T3 cells is reversed from a clockwise (CW) bias to a counterclockwise (CCW) bias on ring-shaped micropatterns, accompanied by the reversal in cell directional migration. The Ser-39 fascin-actin binding sites are further explored in cell chirality regulation. The findings of this study reveal the critical role of fascin as an important intermediator in cell chirality, shedding novel insights into the mechanisms of L-R asymmetric cell migration and multicellular morphogenesis.

Updates on drug designing approach through computational strategies: a review

The drug discovery and development (DDD) process in pursuit of novel drug candidates is a challenging procedure requiring lots of time and resources. Therefore, computer-aided drug design (CADD) methodologies are used extensively to promote proficiency in drug development in a systematic and time-effective manner. The point in reference is SARS-CoV-2 which has emerged as a global pandemic. In the absence of any confirmed drug moiety to treat the infection, the science fraternity adopted hit and trial methods to come up with a lead drug compound. This article is an overview of the virtual methodologies, which assist in finding novel hits and help in the progression of drug development in a short period with a specific medicinal solution.

Photoluminescent ellipsometric circular dichroism

A novel spectroscopic technique, photoluminescent ellipsometric circular dichroism (PECD), which distinguishes all radiative electronic transitions related to molecular chiral centers. Additionally, it is proposed as complementary to the ellipsometric Raman spectroscopy (ERS) technique, thus establishing a relationship between vibrational modes and electronic transitions, associated with molecular chiral centers. In this way, PECD turns into a powerful technique for chiral material characterization. The PECD technique was performed on a chiral oligomer (1R,2R)-diiminocyclohexane, and its derivative polymer. A complete photophysical characterization in solution was performed to corroborate the new PECD technique.

The Drosophila AWP1 ortholog Doctor No regulates JAK/STAT signaling for left-right asymmetry in the gut by promoting receptor endocytosis

Many organs of Drosophila show stereotypical left-right (LR) asymmetry; however, the underlying mechanisms remain elusive. Here, we have identified an evolutionarily conserved ubiquitin-binding protein, AWP1/Doctor No (Drn), as a factor required for LR asymmetry in the embryonic anterior gut. We found that drn is essential in the circular visceral muscle cells of the midgut for JAK/STAT signaling, which contributes to the first known cue for anterior gut lateralization via LR asymmetric nuclear rearrangement. Embryos homozygous for drn and lacking its maternal contribution showed phenotypes similar to those with depleted JAK/STAT signaling, suggesting that Drn is a general component of JAK/STAT signaling. Absence of Drn resulted in specific accumulation of Domeless (Dome), the receptor for ligands in the JAK/STAT signaling pathway, in intracellular compartments, including ubiquitylated cargos. Dome colocalized with Drn in wild-type Drosophila. These results suggest that Drn is required for the endocytic trafficking of Dome, which is a crucial step for activation of JAK/STAT signaling and the subsequent degradation of Dome. The roles of AWP1/Drn in activating JAK/STAT signaling and in LR asymmetric development may be conserved in various organisms.

Ultrafast Coherent Delocalization Revealed in Multilayer QDs under a Chiral Potential

In recent years, it was found that current passing through chiral molecules exhibits spin preference, an effect known as Chiral Induced Spin Selectivity (CISS). The effect also enables the reduction of scattering and therefore enhances delocalization. As a result, the delocalization of an exciton generated in the dots is not symmetric and relates to the electronic and hole excited spins. In this work utilizing fast spectroscopy on hybrid multilayered QDs with a chiral polypeptide linker system, we probed the interdot chiral coupling on a short time scale. Surprisingly, we found strong coherent coupling and delocalization despite having long 4-nm chiral linkers. We ascribe the results to asymmetric delocalization that is controlled by the electron spin. The effect is not measured when using shorter nonchiral linkers. As the system mimics light-harvesting antennas, the results may shed light on a mechanism of fast and efficient energy transfer in these systems.

Cell jamming regulates epithelial chiral morphogenesis

Internal organs such as the heart demonstrate apparent left-right (LR) asymmetric morphology and positioning. Cellular chirality and associated LR biased mechanical behavior such as cell migration have been attributed to LR symmetry breaking during embryonic development. Mathematical models have shown that chiral directional migration can be driven by cellular intrinsic torque. Tissue jamming state (i.e., solid-like vs fluid-like state) strongly regulates collective migratory behavior, but how it might affect chiral morphogenesis is still unknown. Here, we develop a cell vertex model to study the role of tissue rigidity or jamming state on chiral morphogenesis of the cells on a patterned ring-shaped tissue, simulating a previously reported experimental setup for measuring cell chirality. We simulate chirality as torsional forces acting on cell vertices. As expected, the cells undergo bidirectional migration at the opposing (inner and outer) boundaries of the ring-shaped tissue. We discover that more fluid-like tissues (unjammed) demonstrate a stronger chiral cell alignment and elongation than more solid-like (jammed) tissues and maintain a bigger difference in migration velocity between opposing tissue boundaries. Finally, we find that fluid-like tissues undergo more cell-neighbor exchange events. This study reveals that chiral torque is sufficient to achieve a biased cellular alignment as seen in vitro. It further sheds light on the mechanical regulation of chiral morphogenesis of tissues and reveals a role of cell density-independent tissue rigidity in this process.

Understanding laterality disorders and the left-right organizer: Insights from zebrafish

Vital internal organs display a left-right (LR) asymmetric arrangement that is established during embryonic development. Disruption of this LR asymmetry-or laterality-can result in congenital organ malformations. Situs inversus totalis (SIT) is a complete concordant reversal of internal organs that results in a low occurrence of clinical consequences. Situs ambiguous, which gives rise to Heterotaxy syndrome (HTX), is characterized by discordant development and arrangement of organs that is associated with a wide range of birth defects. The leading cause of health problems in HTX patients is a congenital heart malformation. Mutations identified in patients with laterality disorders implicate motile cilia in establishing LR asymmetry. However, the cellular and molecular mechanisms underlying SIT and HTX are not fully understood. In several vertebrates, including mouse, frog and zebrafish, motile cilia located in a "left-right organizer" (LRO) trigger conserved signaling pathways that guide asymmetric organ development. Perturbation of LRO formation and/or function in animal models recapitulates organ malformations observed in SIT and HTX patients. This provides an opportunity to use these models to investigate the embryological origins of laterality disorders. The zebrafish embryo has emerged as an important model for investigating the earliest steps of LRO development. Here, we discuss clinical characteristics of human laterality disorders, and highlight experimental results from zebrafish that provide insights into LRO biology and advance our understanding of human laterality disorders.

Demystifying racemic natural products in the homochiral world

Natural products possess structural complexity, diversity and chirality with attractive functions and biological activities that have significantly impacted drug discovery initiatives. Chiral natural products are abundant in nature but rarely occur as racemates. The occurrence of natural products as racemates is very intriguing from a biosynthetic point of view; as enzymes are chiral molecules, enzymatic reactions generating natural products should be stereospecific and lead to single-enantiomer products. Despite several reports in the literature describing racemic mixtures of stereoisomers isolated from natural sources, there has not been a comprehensive review of these intriguing racemic natural products. The discovery of many more natural racemates and their potential enzymatic sources in recent years allows us to describe the distribution and chemical diversity of this 'class of natural products' to enrich discussions on biosynthesis. In this Review, we describe the chemical classes, occurrence and distribution of pairs of enantiomers in nature and provide insights about recent advances in analytical methods used for their characterization. Special emphasis is on the biosynthesis, including plausible enzymatic and non-enzymatic formation of natural racemates, and their pharmacological significance.

Changes in and asymmetry of the proteome in the human fetal frontal lobe during early development

Inherent hemispheric asymmetry is important for cognition, language and other functions. Describing normal brain and asymmetry development during early development will improve our understanding of how different hemispheres prioritize specific functions, which is currently unknown. Here, we analysed developmental changes in and asymmetry of the proteome in the bilateral frontal lobes of three foetal specimens in the late first trimester of pregnancy. We found that during this period, the difference in expression between gestational weeks (GWs) increased, and the difference in asymmetric expression decreased. Changes in the patterns of protein expression differed in the bilateral frontal lobes. Our results show that brain asymmetry can be observed in early development. These findings can guide researchers in further investigations of the mechanisms of brain asymmetry. We propose that both sides of the brain should be analysed separately in future multiomics and human brain mapping studies.

Recognition of 3D Chiral Microenvironments for Myoblast Differentiation

Cell chirality plays a critical role in the linkage between molecular chirality and the asymmetrical biological functions of body organs. However, enantioselective interactions between cell chirality and the extracellular environment are not yet fully understood. In this study, we investigated the effects of structurally chiral extracellular microenvironments on cellular alignments and differentiations. Twisted wrinkle-shaped chiral micropatterns were prepared using biaxial and asymmetric buckling methods, wherein structural handedness was determined from the orientation of the tilt angle between the first and second microwrinkles. Myoblasts were separately cultured on two enantiomeric chiral micropatterns in a mirror-reflected shape. Cells cultured on the left-handed chiral micropatterns preferred alignments along the direction of the second microwrinkle, with a relatively deeper valley than that of the first microwrinkle. The aligned cells on the left-handed pattern showed higher differentiation rates, as assessed by fusion indices and marker protein expression levels, than those cultured on right-handed chiral micropatterns. These results suggest that myoblasts exhibit enantioselective recognition of structurally chiral microenvironments, which can promote cellular alignments and differentiation.

Role of Symmetry Breaking in Observing Strong Molecule-Cavity Coupling Using Dielectric Microspheres

The emergence of dielectric open optical cavities has opened a new research avenue in nanophotonics. In particular, dielectric microspheres support a rich set of cavity modes with varying spectral characteristics, making them an ideal platform to study molecule-cavity interactions. The symmetry of the structure plays a critical role in the outcoupling of these modes and, hence, the perceived molecule-cavity coupling strength. Here, we experimentally and theoretically study molecule-cavity coupling mediated by the Mie scattering modes of a dielectric microsphere placed on a glass substrate and excited with far-field illumination, from which we collect scattering signatures both in the air and glass sides. Glass-side collection reveals clear signatures of strong molecule-cavity coupling (coupling strength 2g = 74 meV), in contrast to the air-side scattering signal. Rigorous electromagnetic modeling allows us to understand molecule-cavity coupling and unravel the role played by the spatial mode profile in the observed coupling strength.

A Micropatterning Assay for Measuring Cell Chirality

Chirality is an intrinsic cellular property, which depicts the asymmetry in terms of polarization along the left-right axis of the cell. As this unique property attracts increasing attention due to its important roles in both development and disease, a standardized quantification method for characterizing cell chirality would advance research and potential applications. In this protocol, we describe a multicellular chirality characterization assay that utilizes micropatterned arrays of cells. Cellular micropatterns are fabricated on titanium/gold-coated glass slides via microcontact printing. After seeding on the geometrically defined (e.g., ring-shaped), protein-coated islands, cells directionally migrate and form a biased alignment toward either the clockwise or the counterclockwise direction, which can be automatically analyzed and quantified by a custom-written MATLAB program. Here we describe in detail the fabrication of micropatterned substrates, cell seeding, image collection, and data analysis and show representative results obtained using the NIH/3T3 cells. This protocol has previously been validated in multiple published studies and is an efficient and reliable tool for studying cell chirality in vitro.

Attachment of Chiral Functional Groups to Modify the Activity of New GPx Mimetics

A series of new chiral benzisoselenazol-3(2H)-ones and their corresponding diselenides bearing an o-amido function substituted on the nitrogen atom with various aliphatic and aromatic moieties were synthesized. All derivatives representing pairs of enantiomers or diastereoisomers were obtained to thoroughly evaluate the three-dimensional structure-activity correlation. First, bensisoselenazol-3(2H)-ones were synthesized by reacting 2-(chloroseleno)benzoyl chloride with an appropriate enantiomerically pure amine. Then, the Se-N bond was cleaved by a reduction-oxidation procedure using sodium borohydride and then air oxidation to obtain the corresponding diselenides. All derivatives were tested as antioxidants and anticancer agents. In general, the diselenides were more reactive peroxide scavengers, with the highest activity observed for 2,2'-diselenobis[N-(1S,2S)-(-)-trans-2-hydroksy-1-indanylbezamide]. The most cytotoxic derivative towards human promyelocytic leukemia HL-60 and breast cancer MCF-7 cell lines was N-[(1S,2R)-(-)-cis-2-hydroksy-1-indanyl]-1,2-benzizoselenazol-3(2H)-one. The structure-activity relationship of the obtained organoselenium derivatives was discussed.

Anterior-posterior pattern formation in ciliates

As single cells, ciliates build, duplicate, and even regenerate complex cortical patterns by largely unknown mechanisms that precisely position organelles along two cell‐wide axes: anterior–posterior and circumferential (left–right). We review our current understanding of intracellular patterning along the anterior–posterior axis in ciliates, with emphasis on how the new pattern emerges during cell division. We focus on the recent progress at the molecular level that has been driven by the discovery of genes whose mutations cause organelle positioning defects in the model ciliate Tetrahymena thermophila. These investigations have revealed a network of highly conserved kinases that are confined to either anterior or posterior domains in the cell cortex. These pattern‐regulating kinases create zones of cortical inhibition that by exclusion determine the precise placement of organelles. We discuss observations and models derived from classical microsurgical experiments in large ciliates (including Stentor) and interpret them in light of recent molecular findings in Tetrahymena. In particular, we address the involvement of intracellular gradients as vehicles for positioning organelles along the anterior‐posterior axis.

Fundamental Clock of Biological Aging: Convergence of Molecular, Neurodegenerative, Cognitive and Psychiatric Pathways: Non-Equilibrium Thermodynamics Meet Psychology

In humans, age-associated degrading changes, widely observed in molecular and cellular processes underly the time-dependent decline in spatial navigation, time perception, cognitive and psychological abilities, and memory. Cross-talk of biological, cognitive, and psychological clocks provides an integrative contribution to healthy and advanced aging. At the molecular level, genome, proteome, and lipidome instability are widely recognized as the primary causal factors in aging. We narrow attention to the roles of protein aging linked to prevalent amino acids chirality, enzymatic and spontaneous (non-enzymatic) post-translational modifications (PTMs ^SP), and non-equilibrium phase transitions. The homochirality of protein synthesis, resulting in the steady-state non-equilibrium condition of protein structure, makes them prone to multiple types of enzymatic and spontaneous PTMs, including racemization and isomerization. Spontaneous racemization leads to the loss of the balanced prevalent chirality. Advanced biological aging related to irreversible PTMs ^SP has been associated with the nontrivial interplay between somatic (molecular aging) and mental (psychological aging) health conditions. Through stress response systems (SRS), the environmental and psychological stressors contribute to the age-associated “collapse” of protein homochirality. The role of prevalent protein chirality and entropy of protein folding in biological aging is mainly overlooked. In a more generalized context, the time-dependent shift from enzymatic to the non-enzymatic transformation of biochirality might represent an important and yet underappreciated hallmark of aging. We provide the experimental arguments in support of the racemization theory of aging.