Remodeling of Murine Branch Pulmonary Arteries Under Chronic Hypoxia and Short-Term Normoxic Recovery

Chronic hypoxia plays a central role in diverse pulmonary pathologies, but its effects on longitudinal changes in the biomechanical behavior of proximal pulmonary arteries remain poorly understood. Similarly, effects of normoxic recovery have not been well studied. Here, we report hypoxia-induced changes in composition, vasoactivity, and passive biaxial mechanics in the main branch pulmonary artery of male C57BL/6J mice exposed to 10% FiO2 for 1, 2, or 3 weeks. We observed significant changes in extracellular matrix, and consequently wall mechanics, as early as 1 week of hypoxia. While circumferential stress and stiffness returned toward normal values by 2-3 weeks of hypoxia, area fractions of cytoplasm and thin collagen fibers did not return toward normal until after 1 week of normoxic recovery. By contrast, elastic energy storage and overall distensibility remained reduced after 3 weeks of hypoxia as well as following 1 week of normoxic recovery. While smooth muscle and endothelial cell responses were attenuated under hypoxia, smooth muscle but not endothelial cell responses recovered following 1 week of subsequent normoxia. Collectively, these data suggest that homeostatic processes were unable to preserve or restore overall function, at least over a brief period of normoxic recovery. Longitudinal changes are critical in understanding large pulmonary artery remodeling under hypoxia, and its reversal, and will inform predictive models of vascular adaptation.

Cross-talk and mutual shaping between the immune system and the microbiota during an oyster's life

The Pacific oyster Crassostrea gigas lives in microbe-rich marine coastal systems subjected to rapid environmental changes. It harbours a diversified and fluctuating microbiota that cohabits with immune cells expressing a diversified immune gene repertoire. In the early stages of oyster development, just after fertilization, the microbiota plays a key role in educating the immune system. Exposure to a rich microbial environment at the larval stage leads to an increase in immune competence throughout the life of the oyster, conferring a better protection against pathogenic infections at later juvenile/adult stages. This beneficial effect, which is intergenerational, is associated with epigenetic remodelling. At juvenile stages, the educated immune system participates in the control of the homeostasis. In particular, the microbiota is fine-tuned by oyster antimicrobial peptides acting through specific and synergistic effects. However, this balance is fragile, as illustrated by the Pacific Oyster Mortality Syndrome, a disease causing mass mortalities in oysters worldwide. In this disease, the weakening of oyster immune defences by OsHV-1 µVar virus induces a dysbiosis leading to fatal sepsis. This review illustrates the continuous interaction between the highly diversified oyster immune system and its dynamic microbiota throughout its life, and the importance of this cross-talk for oyster health. This article is part of the theme issue 'Sculpting the microbiome: how host factors determine and respond to microbial colonization'.

Alternative Renin-Angiotensin System

The renin-angiotensin system is the most important peptide hormone system in the regulation of cardiovascular homeostasis. Its classical arm consists of the enzymes, renin, and angiotensin-converting enzyme, generating angiotensin II from angiotensinogen, which activates its AT1 receptor, thereby increasing blood pressure, retaining salt and water, and inducing cardiovascular hypertrophy and fibrosis. However, angiotensin II can also activate a second receptor, the AT2 receptor. Moreover, the removal of the C-terminal phenylalanine from angiotensin II by ACE2 (angiotensin-converting enzyme 2) yields angiotensin-(1-7), and this peptide interacts with its receptor Mas. When the aminoterminal Asp of angiotensin-(1-7) is decarboxylated, alamandine is generated, which activates the Mas-related G-protein-coupled receptor D, MrgD (Mas-related G-protein-coupled receptor type D). Since Mas, MrgD, and the AT2 receptor have opposing effects to the classical AT1 receptor, they and the enzymes and peptides activating them are called the alternative or protective arm of the renin-angiotensin system. This review will cover the historical aspects and the current standing of this recent addition to the biology of the renin-angiotensin system.

Interactions Between HDL and CD4+ T Cells: A Novel Understanding of HDL Anti-Inflammatory Properties

Several studies in animal models and human cohorts have recently suggested that HDLs (high-density lipoproteins) not only modulate innate immune responses but also adaptative immune responses, particularly CD4+ T cells. CD4+ T cells are central effectors and regulators of the adaptive immune system, and any alterations in their homeostasis contribute to the pathogenesis of cardiovascular diseases, autoimmunity, and inflammatory diseases. In this review, we focus on how HDLs and their components affect CD4+ T-cell homeostasis by modulating cholesterol efflux, immune synapsis, proliferation, differentiation, oxidative stress, and apoptosis. While the effects of apoB-containing lipoproteins on T cells have been relatively well established, this review focuses specifically on new connections between HDL and CD4+ T cells. We present a model where HDL may modulate T cells through both direct and indirect mechanisms.

Change of voltage-gated sodium channel repertoire in skeletal muscle of a MuSK myasthenia gravis mouse model

Muscle-specific kinase myasthenia gravis (MuSK MG) is caused by autoantibodies against MuSK in the neuromuscular junction (NMJ). MuSK MG patients have fluctuating, fatigable skeletal muscle weakness, in particular of bulbar muscles. Severity differs greatly between patients, in spite of comparable autoantibody levels. One explanation for inter-patient and inter-muscle variability in sensitivity might be variations in compensatory muscle responses. Previously, we developed a passive transfer mouse model for MuSK MG. In preliminary ex vivo experiments, we observed that muscle contraction of some mice, in particular those with milder myasthenia, had become partially insensitive to inhibition by μ-Conotoxin-GIIIB, a blocker of skeletal muscle NaV1.4 voltage-gated sodium channels. We hypothesised that changes in NaV channel expression profile, possibly co-expression of (μ-Conotoxin-GIIIB insensitive) NaV1.5 type channels, might lower the muscle fibre's firing threshold and facilitate neuromuscular synaptic transmission. To test this hypothesis, we here performed passive transfer in immuno-compromised mice, using 'high', 'intermediate' and 'low' dosing regimens of purified MuSK MG patient IgG4. We compared myasthenia levels, μ-Conotoxin-GIIIB resistance and muscle fibre action potential characteristics and firing thresholds. High- and intermediate-dosed mice showed clear, progressive myasthenia, not seen in low-dosed animals. However, diaphragm NMJ electrophysiology demonstrated almost equal myasthenic severities amongst all regimens. Nonetheless, low-dosed mouse diaphragms showed a much higher degree of μ-Conotoxin-GIIIB resistance. This was not explained by upregulation of Scn5a (the NaV1.5 gene), lowered muscle fibre firing thresholds or histologically detectable upregulated NaV1.5 channels. It remains to be established which factors are responsible for the observed μ-Conotoxin-GIIIB insensitivity and whether the NaV repertoire change is compensatory beneficial or a bystander effect.

Low-Temperature Synthesis of WSe2 by the Selenization Process under Ultrahigh Vacuum for BEOL Compatible Reconfigurable Neurons

Low-temperature large-area growth of two-dimensional (2D) transition-metal dichalcogenides (TMDs) is critical for their integration with silicon chips. Especially, if the growth temperatures can be lowered below the back-end-of-line (BEOL) processing temperatures, the Si transistors can interface with 2D devices (in the back end) to enable high-density heterogeneous circuits. Such configurations are particularly useful for neuromorphic computing applications where a dense network of neurons interacts to compute the output. In this work, we present low-temperature synthesis (400 °C) of 2D tungsten diselenide (WSe2) via the selenization of the W film under ultrahigh vacuum (UHV) conditions. This simple yet effective process yields large-area, homogeneous films of 2D TMDs, as confirmed by several characterization techniques, including reflection high-energy electron diffraction, atomic force microscopy, transmission electron microscopy, and different spectroscopy methods. Memristors fabricated using the grown WSe2 film are leveraged to realize a novel compact neuron circuit that can be reconfigured to enable homeostasis.

Eosinophil Plasticity and Diversity: Proceedings of the 2023 International Eosinophil Society Symposium

This issue highlights and details the programme and scientific presentations at the International Eosinophil Society's 12th biennial Symposium, which was held in Hamilton, Ontario, Canada in July 2023. The meeting included sessions on regulation of eosinophil development; cell death, stress, and autophagy in eosinophils; local immunity interactions of eosinophils with multiple cell types; eosinophils in host defense; eosinophils and mast cells in gastrointestinal disorders; reciprocal interactions between eosinophils and the microbiome in homeostasis and dysbiosis; and, eosinophils in tissue injury and repair, in tumor biology and cancer therapy. There was a mixture of special invited lectures and cutting-edge abstracts on specific aspects of eosinophil science, as well as enlivened pro-con debates on targeting eosinophils with biologics. A major thrust and overarching theme was that eosinophils exhibit remarkable plasticity and heterogeneity in executing their functions both in homeostasis and in pathobiology; there is a new "Eo-verse" to understand. We trust that this special volume of the Journal of Leukocyte Biology will be of interest across many disciplines and medical sub-specialties in biomedical sciences and demonstrate both the complexity and versatility of the eosinophil in biology and medicine.

Towards Prolonging Ovarian Reproductive Life: Insights into Trace Elements Homeostasis

Ovarian aging is marked by a reduction in the quantity and quality of ovarian follicles, leading to a decline in female fertility and ovarian endocrine function. While the biological characteristics of ovarian aging are well-established, the exact mechanisms underlying this process remain elusive. Recent studies underscore the vital role of trace elements (TEs) in maintaining ovarian function. Imbalances in TEs can lead to ovarian aging, characterized by reduced enzyme activity, hormonal imbalances, ovulatory disorders, and decreased fertility. A comprehensive understanding of the relationship between systemic and cellular TEs balance and ovarian aging is critical for developing treatments to delay aging and manage age-related conditions. This review consolidates current insights into TEs homeostasis and its impact on ovarian aging, assesses how altered TEs metabolism affects ovarian aging, and suggests future research directions to prolong ovarian reproductive life. These studies are expected to offer novel approaches for mitigating ovarian aging.

Autophagy: a key player in the recovery of plants from heat stress

Plants can be primed to withstand otherwise lethal heat stress (HS) through exposure to a preceding temporary and mild HS, commonly known as the 'thermopriming stimulus'. Plants have also evolved mechanisms to establish 'memories' of a previous stress encounter, or to reset their physiology to the original cellular state once the stress has ended. The priming stimulus triggers a widespread change of transcripts, proteins, and metabolites, which is crucial for maintaining the memory state but may not be required for growth and development under optimal conditions or may even be harmful. In such a scenario, recycling mechanisms such as autophagy are crucial for re-establishing cellular homeostasis and optimizing resource use for post-stress growth. While pivotal for eliminating heat-induced protein aggregates and protecting plants from the harmful impact of HS, recent evidence implies that autophagy also breaks down heat-induced protective macromolecules, including heat shock proteins, functioning as a resetting mechanism during the recovery from mild HS. This review provides an overview of the latest advances in understanding the multifaceted functions of autophagy in HS responses, with a specific emphasis on its roles in recovery from mild HS, and the modulation of HS memory.

Zinc and manganese homeostasis closely interact in mammalian cells

Understanding the homeostatic interactions among essential trace metals is important for explaining their roles in cellular systems. Recent studies in vertebrates suggest that cellular Mn metabolism is related to Zn metabolism in multifarious cellular processes. However, the underlying mechanism remains unclear. In this study, we examined the changes in the expression of proteins involved in cellular Zn and/or Mn homeostatic control and measured the Mn as well as Zn contents and Zn enzyme activities to elucidate the effects of Mn and Zn homeostasis on each other. Mn treatment decreased the expression of the Zn homeostatic proteins metallothionein (MT) and ZNT1 and reduced Zn enzyme activities, which were attributed to the decreased Zn content. Moreover, loss of Mn efflux transport protein decreased MT and ZNT1 expression and Zn enzyme activity without changing extracellular Mn content. This reduction was not observed when supplementing with the same Cu concentrations and in cells lacking Cu efflux proteins. Furthermore, cellular Zn homeostasis was oppositely regulated in cells expressing Zn and Mn importer ZIP8, depending on whether Zn or Mn concentration was elevated in the extracellular milieu. Our results provide novel insights into the intricate interactions between Mn and Zn homeostasis in mammalian cells and facilitate our understanding of the physiopathology of Mn, which may lead to the development of treatment strategies for Mn-related diseases in the future.

Decoupling cell size homeostasis in diatoms from the geometrical constraints of the silica cell wall

Unicellular organisms are known to exert tight control over their cell size. In the case of diatoms, abundant eukaryotic microalgae, two opposing notions are widely accepted. On the one hand, the rigid silica cell wall that forms inside the parental cell is thought to enforce geometrical reduction of the cell size. On the other hand, numerous exceptions cast doubt on the generality of this model. Here, we monitored clonal cultures of the diatom Stephanopyxis turris for up to 2 yr, recording the sizes of thousands of cells, in order to follow the distribution of cell sizes in the population. Our results show that S. turris cultures above a certain size threshold undergo a gradual size reduction, in accordance with the postulated geometrical driving force. However, once the cell size reaches a lower threshold, it fluctuates around a constant size using the inherent elasticity of cell wall elements. These results reconcile the disparate observations on cell size regulation in diatoms by showing two distinct behaviors, reduction and homeostasis. The geometrical size reduction is the dominant driving force for large cells, but smaller cells have the flexibility to re-adjust the size of their new cell walls.

Rapamycin alleviates irradiation-induced parotid injury by enhancing the whole gland homeostasis

OBJECTIVES

Salivary gland injury is one of the most common complications of radiotherapy in head-and-neck cancers. This study investigated the mechanism by which rapamycin prevents irradiation (IR)-induced injury in the parotid glands.

MATERIALS AND METHODS

Miniature pigs either received (a) no treatment (NT), (b) IR in the right parotid gland for 5 consecutive days (IR), or intraperitoneal administration of rapamycin (Rap) 1 h prior to IR (IR + Rap). Tissues were collected at three distinct time points (24 h, 4 weeks, and 16 weeks) after IR. Histological analyses, western blot, and real-time reverse transcriptase-polymerase chain reaction were performed to explore the mechanisms of IR-induced injury in the parotid gland.

RESULTS

Rapamycin treatment maintained parotid salivary flow 16 weeks post-IR, preserved the number of acinar cells, and reduced parotid tissue fibrosis, as well as reduced apoptosis levels, decreased cleaved caspase-3 expression, and increased the Bcl-2/Bax ratio in the parotid glands. Autophagy marker LC3B was upregulated by rapamycin after IR, while P62 expression was downregulated. Rapamycin reduced the expression of pro-inflammatory factors and the mesenchymal tissue fibrosis following IR.

CONCLUSIONS

Rapamycin maintains gland homeostasis after IR by decreasing apoptosis, reducing the expression of pro-inflammatory factors, and enhancing autophagy.

High-density electroencephalographic functional networks in genetic generalized epilepsy: Preserved whole-brain topology hides local reorganization

OBJECTIVE

Genetic generalized epilepsy (GGE) accounts for approximately 20% of adult epilepsy cases and is considered a disorder of large brain networks, involving both hemispheres. Most studies have not shown any difference in functional whole-brain network topology when compared to healthy controls. Our objective was to examine whether this preserved global network topology could hide local reorganizations that balance out at the global network level.

METHODS

We recorded high-density electroencephalograms from 20 patients and 20 controls, and reconstructed the activity of 118 regions. We computed functional connectivity in windows free of interictal epileptiform discharges in broad, delta, theta, alpha, and beta frequency bands, characterized the network topology, and used the Hub Disruption Index (HDI) to quantify the topological reorganization. We examined the generalizability of our results by reproducing a 25-electrode clinical system.

RESULTS

Our study did not reveal any significant change in whole-brain network topology among GGE patients. However, the HDI was significantly different between patients and controls in all frequency bands except alpha (p < .01, false discovery rate [FDR] corrected, d < -1), and accompanied by an increase in connectivity in the prefrontal regions and default mode network. This reorganization suggests that regions that are important in transferring the information in controls were less so in patients. Inversely, the crucial regions in patients are less so in controls. These findings were also found in delta and theta frequency bands when using 25 electrodes (p < .001, FDR corrected, d < -1).

SIGNIFICANCE

In GGE patients, the overall network topology is similar to that of healthy controls but presents a balanced local topological reorganization. This reorganization causes the prefrontal areas and default mode network to be more integrated and segregated, which may explain executive impairment associated with GGE. Additionally, the reorganization distinguishes patients from controls even when using 25 electrodes, suggesting its potential use as a diagnostic tool.

When Studying Affective Responses to Exercise, the Definition of "Intensity" Must Reference Homeostatic Perturbations: A Retort to Vollaard et al

In articles on the methodology of studies investigating affective and enjoyment responses to high-intensity interval training, we noted that, occasionally, exercise conditions described as involving "high" intensity exhibited heart rates that were only as high as, or even lower than, heart rates recorded during comparator conditions described as being of "moderate" intensity. Drs. Vollaard, Metcalfe, Kinghorn, Jung, and Little suggest instead that exercise intensity in high-intensity interval-training studies can be defined in terms of percentages of peak workload. Although we maintain that defining exercise intensity in terms of percentages of maximal heart rate is a suboptimal way to quantify the degree of homeostatic perturbations in response to exercise, we are unconvinced that definitions of intensity relying solely on workload are appropriate for studies investigating affective and enjoyment responses to exercise. The reason is that affect is theorized to have evolved to relay information about homeostatic perturbations to consciousness.

Tissue-specific transcriptional programming of macrophages controls the microRNA transcriptome targeting multiple functional pathways

Recent interest in the biology and function of peritoneal tissue resident macrophages (pMΦ) has led to a better understanding of their cellular origin, programming and renewal. The programming of pMΦ is dependent on microenvironmental cues and tissue specific transcription factors, including GATA6. However, the contribution of microRNAs remains poorly defined. We conducted a detailed analysis of the impact of GATA6-deficiency on microRNA expression in mouse pMΦ. Our data suggest that for many of the pMΦ, microRNA composition may be established during tissue specialization, and that the effect of GATA6 knockout is largely unable to be rescued in the adult by exogenous GATA6. The data are consistent with GATA6 modulating the expression pattern of specific microRNAs, directly or indirectly, and including miR-146a, -223, and -203 established by the lineage-determining transcription factor PU.1, to achieve a differentiated pMΦ phenotype. Lastly, we showed a significant dysregulation of miR-708 in pMΦ in the absence of GATA6 during homeostasis and in response to LPS/IFN-γ stimulation. Overexpression of miR-708 in mouse pMΦ in vivo altered 167 mRNA species demonstrating functional downregulation of predicted targets, including cell immune responses and cell cycle regulation. In conclusion, we demonstrate dependence of the microRNA transcriptome on tissue-specific programming of tissue macrophages as exemplified by the role of GATA6 in pMΦ specialization.

Piezo1 channel exaggerates ferroptosis of nucleus pulposus cells by mediating mechanical stress-induced iron influx

To date, several molecules have been found to facilitate iron influx, while the types of iron influx channels remain to be elucidated. Here, Piezo1 channel was identified as a key iron transporter in response to mechanical stress. Piezo1-mediated iron overload disturbed iron metabolism and exaggerated ferroptosis in nucleus pulposus cells (NPCs). Importantly, Piezo1-induced iron influx was independent of the transferrin receptor (TFRC), a well-recognized iron gatekeeper. Furthermore, pharmacological inactivation of Piezo1 profoundly reduced iron accumulation, alleviated mitochondrial ROS, and suppressed ferroptotic alterations in stimulation of mechanical stress. Moreover, conditional knockout of Piezo1 (Col2a1-CreERT Piezo1flox/flox) attenuated the mechanical injury-induced intervertebral disc degeneration (IVDD). Notably, the protective effect of Piezo1 deficiency in IVDD was dampened in Piezo1/Gpx4 conditional double knockout (cDKO) mice (Col2a1-CreERT Piezo1flox/flox/Gpx4flox/flox). These findings suggest that Piezo1 is a potential determinant of iron influx, indicating that the Piezo1-iron-ferroptosis axis might shed light on the treatment of mechanical stress-induced diseases.

scRNA-seq data from the larval Drosophila ventral cord provides a resource for studying motor systems function and development

The Drosophila larval ventral nerve cord (VNC) shares many similarities with the spinal cord of vertebrates and has emerged as a major model for understanding the development and function of motor systems. Here, we use high-quality scRNA-seq, validated by anatomical identification, to create a comprehensive census of larval VNC cell types. We show that the neural lineages that comprise the adult VNC are already defined, but quiescent, at the larval stage. Using fluorescence-activated cell sorting (FACS)-enriched populations, we separate all motor neuron bundles and link individual neuron clusters to morphologically characterized known subtypes. We discovered a glutamate receptor subunit required for basal neurotransmission and homeostasis at the larval neuromuscular junction. We describe larval glia and endorse the general view that glia perform consistent activities throughout development. This census represents an extensive resource and a powerful platform for future discoveries of cellular and molecular mechanisms in repair, regeneration, plasticity, homeostasis, and behavioral coordination.

Inhibiting Peptidoglycan Hydrolase Alleviates MRSA Pneumonia Through Autolysin-Mediated MDP-NOD2 Pathway

Background

Methicillin-resistant Staphylococcus aureus (MRSA) is a cause of staph infection that is difficult to treat because of resistance to some antibiotics. A recent study indicated that diarylurea ZJ-2 is a novel antibacterial agent against multi-drug resistant Enterococcus faecium. In this work, we refined the bactericidal mechanism of ZJ-2 as a peptidoglycan (PG) hydrolase by affecting AtlA-mediated PG homeostasis.

Methods

A wild-type strain (WT) and a mutant strain (ΔatlA) were used to investigate the effects of ZJ-2 on the cell wall, PG, and autolysin regulatory system by antimicrobial susceptibility testing, hemolytic toxin assay, microanalysis, autolysis assay, qRT-PCR, ELISA and mouse model of pneumonia.

Results

The results revealed that ZJ-2 down-regulated the expression of genes related to peptidoglycan hydrolase (PGH) (sprX, walR, atlA, and lytM), and reduced the levels of PG, muramyl dipeptide (MDP), cytokines, and hemolytic toxin, while ΔatlA interfered with the genes regulation and PG homeostasis. In the mouse MRSA pneumonia model, the same trend was observed in the nucleotide oligomerization domain protein 2 (NOD2) and relative proinflammatory factors.

Conclusion

ZJ-2 may act as a novel inhibitor of PG hydrolyse, disrupting autolysin-mediated PG homeostasis, and reducing inflammation by down-regulating the MDP-NOD2 pathway.

Emerging dimensions of autophagy in melanoma

Macroautophagy/autophagy has previously been regarded as simply a way for cells to deal with nutrient emergency. But explosive work in the last 15 years has given increasingly new knowledge to our understanding of this process. Many of the functions of autophagy that are unveiled from recent studies, however, cannot be reconciled with this conventional view of cell survival but, instead, point to autophagy being integrally involved at a deeper level of cell biology, playing a critical role in maintaining homeostasis and promoting an integrated stress/immune response. The new appreciation of the role of autophagy in the evolutionary trajectory of cancer and cancer interaction with the immune system provides a mechanistic framework for understanding the clinical benefits of autophagy-based therapies. Here, we examine current knowledge of the mechanisms and functions of autophagy in highly plastic and aggressive melanoma as a model disease of human malignancy, while highlighting emerging dimensions indicating that autophagy is at play beyond its classical face.Abbreviation: AMBRA1: autophagy and beclin 1 regulator 1; AMPK: AMP-activated protein kinase; ATF4: activating transcription factor 4; ATG: autophagy related; BRAF: B-Raf proto-oncogene, serine/threonine kinase; CAFs: cancer-associated fibroblasts; CCL5: C-C motif chemokine ligand 5; CQ: chloroquine; CRISPR: clustered regularly interspaced short palindromic repeats; CTLA4: cytotoxic T-lymphocyte associated protein 4; CTL: cytotoxic T lymphocyte; DAMPs: danger/damage-associated molecular patterns; EGFR: epidermal growth factor receptor; EIF2A/eIF2α: eukaryotic translation initiation factor 2A; EIF2AK3/PERK: eukaryotic translation initiation factor 2 alpha kinase 3; ER: endoplasmic reticulum; FITM2: fat storage inducing transmembrane protein 2; HCQ: hydroxychloroquine; ICB: immune checkpoint blockade; ICD: immunogenic cell death; LDH: lactate dehydrogenase; MAPK: mitogen-activated protein kinase; MTORC1: mechanistic target of rapamycin kinase complex 1; NDP52: nuclear dot protein 52; NFKB/NF-κ B: nuclear factor kappa B; NBR1: the neighbor of BRCA1; NK: natural killer; NRF1: nuclear respiratory factor 1; NSCLC: non-small-cell lung cancer; OPTN: optineurin; PDAC: pancreatic ductal adenocarcinoma; PDCD1/PD-1: programmed cell death 1; PPT1: palmitoyl-protein thioesterase 1; PTEN: phosphatase and tensin homolog; PTK2/FAK1: protein tyrosine kinase 2; RAS: rat sarcoma; SQSTM1/p62: sequestosome 1; STK11/LKB1: serine/threonine kinase 11; TAX1BP1: Tax1 binding protein 1; TFEB: transcription factor EB; TGFB/TGF-β: transforming growth factor beta; TMB: tumor mutational burden; TME: tumor microenvironment; TSC1: TSC complex subunit 1; TSC2: TSC complex subunit 2; ULK1: unc-51 like autophagy activating kinase 1; UVRAG: UV radiation resistance associated.

Common mouse models of chronic kidney disease are not associated with cachexia

The 5/6 nephrectomy and adenine-induced nephropathy mouse models have been extensively used to study Chronic Kidney Disease (CKD)-related cachexia. One common caveat of these CKD models is the cross-sectional nature of comparisons made versus controls. We here performed a comprehensive longitudinal assessment of body composition and energy metabolism in both models. The most striking finding is that weight loss is largely driven by reduced food intake which promotes rapid loss of lean and fat mass. However, in both models, mice catch up weight and lean mass a few days after the surgery or when they are switched back to standard chow diet. Muscle force and mass are fully recovered and no sign of cachexia is observed. Our data demonstrate that the time-course of kidney failure and weight loss are unrelated in these common CKD models. These data highlight the need to reconsider the relative contribution of direct and indirect mechanisms to muscle wasting observed in CKD.

Synaptic homeostasis transiently leverages Hebbian mechanisms for a multiphasic response to inactivity

Homeostatic regulation of synapses is vital for nervous system function and key to understanding a range of neurological conditions. Synaptic homeostasis is proposed to operate over hours to counteract the destabilizing influence of long-term potentiation (LTP) and long-term depression (LTD). The prevailing view holds that synaptic scaling is a slow first-order process that regulates postsynaptic glutamate receptors and fundamentally differs from LTP or LTD. Surprisingly, we find that the dynamics of scaling induced by neuronal inactivity are not exponential or monotonic, and the mechanism requires calcineurin and CaMKII, molecules dominant in LTD and LTP. Our quantitative model of these enzymes reconstructs the unexpected dynamics of homeostatic scaling and reveals how synapses can efficiently safeguard future capacity for synaptic plasticity. This mechanism of synaptic adaptation supports a broader set of homeostatic changes, including action potential autoregulation, and invites further inquiry into how such a mechanism varies in health and disease.

Crosstalk between COVID-19 and the gut-brain axis: a gut feeling

The microbes in the gut are crucial for maintaining the body's immune system and overall gut health. However, it is not fully understood how an unstable gut environment can lead to more severe cases of SARS-CoV-2 infection. The gut microbiota also plays a role in the gut-brain axis and interacts with the central nervous system through metabolic and neuroendocrine pathways. The interaction between the microbiota and the host's body involves hormonal, immune, and neural pathways, and any disruption in the balance of gut bacteria can lead to dysbiosis, which contributes to pathogen growth. In this context, we discuss how dysbiosis could contribute to comorbidities that increase susceptibility to SARS-CoV-2. Probiotics and fecal microbiota transplantation have successfully treated infectious and non-infectious inflammatory-related diseases, the most common comorbidities. These treatments could be adjuvant therapies for COVID-19 infection by restoring gut homeostasis and balancing the gut microbiota.

Circadian Rhythms of the Blood-Brain Barrier and Drug Delivery

The blood-brain barrier (BBB) is a critical interface separating the central nervous system from the peripheral circulation, ensuring brain homeostasis and function. Recent research has unveiled a profound connection between the BBB and circadian rhythms, the endogenous oscillations synchronizing biological processes with the 24-hour light-dark cycle. This review explores the significance of circadian rhythms in the context of BBB functions, with an emphasis on substrate passage through the BBB. Our discussion includes efflux transporters and the molecular timing mechanisms that regulate their activities. A significant focus of this review is the potential implications of chronotherapy, leveraging our knowledge of circadian rhythms for improving drug delivery to the brain. Understanding the temporal changes in BBB can lead to optimized timing of drug administration, to enhance therapeutic efficacy for neurological disorders while reducing side effects. By elucidating the interplay between circadian rhythms and drug transport across the BBB, this review offers insights into innovative therapeutic interventions.

Inverse-Vaccines for Rheumatoid Arthritis Re-establish Metabolic and Immunological Homeostasis in Joint Tissues

Rheumatoid arthritis (RA) causes immunological and metabolic imbalances in tissue, exacerbating inflammation in affected joints. Changes in immunological and metabolic tissue homeostasis at different stages of RA are not well understood. Herein, the changes in the immunological and metabolic profiles in different stages in collagen induced arthritis (CIA), namely, early, intermediate, and late stage is examined. Moreover, the efficacy of the inverse-vaccine, paKG(PFK15+bc2) microparticle, to restore tissue homeostasis at different stages is also investigated. Immunological analyses of inverse-vaccine-treated group revealed a significant decrease in the activation of pro-inflammatory immune cells and remarkable increase in regulatory T-cell populations in the intermediate and late stages compared to no treatment. Also, glycolysis in the spleen is normalized in the late stages of CIA in inverse-vaccine-treated mice, which is similar to no-disease tissues. Metabolomics analyses revealed that metabolites UDP-glucuronic acid and L-Glutathione oxidized are significantly altered between treatment groups, and thus might provide new druggable targets for RA treatment. Flux metabolic modeling identified amino acid and carnitine pathways as the central pathways affected in arthritic tissue with CIA progression. Overall, this study shows that the inverse-vaccines initiate early re-establishment of homeostasis, which persists through the disease span.

Metabolic responses in the gills of Yellowtail Lambari Astyanax lacustris under low- and high-temperature thermal stress

OBJECTIVE

Ectothermic fish are directly affected by temperature changes in the environment. The aim of this study was to evaluate the metabolic responses in the gills of Yellowtail Lambari Astyanax lacustris under thermal stress.

METHODS

To this end, we used spectrophotometry to evaluate the biomarkers of carbohydrate and protein metabolism, antioxidant defense, and oxidative damage in fish subjected to low (15°C) and high (31°C) temperatures, with control groups held at 23°C, for 2, 6, 12, 24, 48, and 96 h.

RESULT

The results showed that cold thermal stress did not change the energy demand, and the antioxidant defense was reduced; therefore, the gills were vulnerable to the action of reactive oxygen species (ROS), presenting increased protein carbonylation at 12 h. With heat thermal stress, a higher energy demand was observed, which was verified by an increase in aerobic metabolism by glycolysis and the citric acid cycle. High-temperature stress also increased the antioxidant defenses, as verified by the increased activities of glutathione peroxidase, glutathione reductase, and glutathione S-transferase. However, the antioxidant defense system could not protect tissues from the action of ROS, as protein carbonylation increased at 6 and 24 h, indicating oxidative stress.

CONCLUSION

The results showed that (1) temperature variations caused metabolic adjustments in the gills of Yellowtail Lambari, (2) the adaptive responses were different for winter and summer temperatures, and (3) Yellowtail Lambari recovered homeostasis when subjected to thermal stress, even with the occurrence of oxidative stress.

Potential Role of the Skin in Hypertension Risk Through Water Conservation

Previous basic and clinical investigations have identified various pathogenic factors and determinants of risk that contribute to hypertension. Nevertheless, the pathogenesis of hypertension has not been fully elucidated. Moreover, despite the availability of antihypertensive medications for the management of blood pressure, treatments that address the full spectrum of the pathophysiological defects underpinning hypertension remain to be identified. To further investigate the mechanisms of primary hypertension, it is imperative to consider novel potential aspects, such as fluid management by the skin, in addition to the conventional risk factors. There is a close association between body fluid regulation and blood pressure, and the kidney, which, as the principal organ responsible for body fluid homeostasis, is the primary target for research in the field of hypertension. In addition, the skin functions as a biological barrier, potentially contributing to body fluid regulation. In this review, we propose the hypothesis that changes in skin water conservation are associated with hypertension risk based on recent findings. Further studies are required to clarify whether this novel hypothesis is limited to specific hypertension or applies to physiological blood pressure regulation.

Tangram of Sodium and Fluid Balance

Homeostasis of fluid and electrolytes is a tightly controlled physiological process. Failure of this process is a hallmark of hypertension, chronic kidney disease, heart failure, and other acute and chronic diseases. While the kidney remains the major player in the control of whole-body fluid and electrolyte homeostasis, recent discoveries point toward more peripheral mechanisms leading to sodium storage in tissues, such as skin and muscle, and a link between this sodium and a range of diseases, including the conditions above. In this review, we describe multiple facets of sodium and fluid balance from traditional concepts to novel discoveries. We examine the differences between acute disruption of sodium balance and the longer term adaptation in chronic disease, highlighting areas that cannot be explained by a kidney-centric model alone. The theoretical and methodological challenges of more recently proposed models are discussed. We acknowledge the different roles of extracellular and intracellular spaces and propose an integrated model that maintains fluid and electrolyte homeostasis and can be distilled into a few elemental players: the microvasculature, the interstitium, and tissue cells. Understanding their interplay will guide a more precise treatment of conditions characterized by sodium excess, for which primary aldosteronism is presented as a prototype.

The ubiquitin codes in cellular stress responses

Ubiquitination/ubiquitylation, one of the most fundamental post-translational modifications, regulates almost every critical cellular process in eukaryotes. Emerging evidence has shown that essential components of numerous biological processes undergo ubiquitination in mammalian cells upon exposure to diverse stresses, from exogenous factors to cellular reactions, causing a dazzling variety of functional consequences. Various forms of ubiquitin signals generated by ubiquitylation events in specific milieus, known as ubiquitin codes, constitute an intrinsic part of myriad cellular stress responses. These ubiquitination events, leading to proteolytic turnover of the substrates or just switch in functionality, initiate, regulate, or supervise multiple cellular stress-associated responses, supporting adaptation, homeostasis recovery, and survival of the stressed cells. In this review, we attempted to summarize the crucial roles of ubiquitination in response to different environmental and intracellular stresses, while discussing how stresses modulate the ubiquitin system. This review also updates the most recent advances in understanding ubiquitination machinery as well as different stress responses and discusses some important questions that may warrant future investigation.

Epigenetic Switches in Retinal Homeostasis and Target for Drug Development

Retinal homeostasis, a tightly regulated process maintaining the functional integrity of the retina, is vital for visual function. Emerging research has unveiled the critical role of epigenetic regulation in controlling gene expression patterns during retinal development, maintenance, and response to mutational loads and injuries. Epigenetic switches, including DNA methylation, histone modifications, and non-coding RNAs, play pivotal roles in orchestrating retinal gene expression and cellular responses through various intracellular, extracellular, and environmental modulators. This review compiles the current knowledge on epigenetic switches in retinal homeostasis, providing a deeper understanding of their impact on retinal structural integrity and function and using them as potential targets for therapeutic interventions.

How do we get from hyperexcitability to excitotoxicity in amyotrophic lateral sclerosis?

Amyotrophic lateral sclerosis is a devastating neurodegenerative disease that, at present, has no effective cure. Evidence of increased circulating glutamate and hyperexcitability of the motor cortex in patients with amyotrophic lateral sclerosis have provided an empirical support base for the 'dying forward' excitotoxicity hypothesis. The hypothesis postulates that increased activation of upper motor neurons spreads pathology to lower motor neurons in the spinal cord in the form of excessive glutamate release, which triggers excitotoxic processes. Many clinical trials have focused on therapies that target excitotoxicity via dampening neuronal activation, but not all are effective. As such, there is a growing tension between the rising tide of evidence for the dying forward excitotoxicity hypothesis and the failure of therapies that target neuronal activation. One possible solution to these contradictory outcomes is that our interpretation of the current evidence requires revision in the context of appreciating the complexity of the nervous system and the limitations of the neurobiological assays we use to study it. In this review we provide an evaluation of evidence relevant to the dying forward excitotoxicity hypothesis and by doing so, identify key gaps in our knowledge that need to be addressed. We hope to provide a roadmap from hyperexcitability to excitotoxicity so that we can better develop therapies for patients suffering from amyotrophic lateral sclerosis. We conclude that studies of upper motor neuron activity and their synaptic output will play a decisive role in the future of amyotrophic lateral sclerosis therapy.

[Advances of proteostasis network and its stability maintenance mechanism]

Protein is fundamental to life, as it generates protein variants. The maintenance of a dynamic equilibrium in these protein variants, known as protein homeostasis, is crucial for cellular function. Various factors, both endogenous and exogenous, can disrupt protein homeostasis during protein synthesis. These factors include translational error, and biological functions mediated by regulatory factors, and more. When cell accumulate proteins with folding errors, it impairs protein homeostasis, leading to the development of related diseases. In response to protein folding errors, multiple monitoring mechanisms are activated to mediate pathways that sustain the dynamic equilibrium. This review highlights the complex relationships within the proteostasis network, which are influenced by a variety of factors. These insights potentially provide new directions for studying diseases caused by protein synthesis errors.

Resisting death by metal: metabolism and Cu/Zn homeostasis in bacteria

Metal ions such as zinc and copper play important roles in host-microbe interactions and their availability can drastically affect the survival of pathogenic bacteria in a host niche. Mechanisms of metal homeostasis protect bacteria from starvation, or intoxication, defined as when metals are limiting, or in excess, respectively. In this mini-review, we summarise current knowledge on the mechanisms of resistance to metal stress in bacteria, focussing specifically on the homeostasis of cellular copper and zinc. This includes a summary of the factors that subvert metal stress in bacteria, which are independent of metal efflux systems, and commentary on the role of small molecules and metabolic systems as important mediators of metal resistance.

Prolactin Mediates Long-Term, Seasonal Rheostatic Regulation of Body Mass in Female Mammals

A series of well-described anabolic and catabolic neuropeptides are known to provide short-term, homeostatic control of energy balance. The mechanisms that govern long-term, rheostatic control of regulated changes in energy balance are less well characterized. Using the robust and repeatable seasonal changes in body mass observed in Siberian hamsters, this report examined the role of prolactin in providing long-term rheostatic control of body mass and photoinduced changes in organ mass (ie, kidney, brown adipose tissue, uterine, and spleen). Endogenous circannual interval timing was observed after 4 months in a short photoperiod, indicated by a significant increase in body mass and prolactin mRNA expression in the pituitary gland. There was an inverse relationship between body mass and the expression of somatostatin (Sst) and cocaine- and amphetamine-regulated transcript (Cart). Pharmacological inhibition of prolactin release (via bromocriptine injection), reduced body mass of animals maintained in long photoperiods to winter-short photoperiod levels and was associated with a significant increase in hypothalamic Cart expression. Administration of ovine prolactin significantly increased body mass 24 hours after a single injection and the effect persisted after 3 consecutive daily injections. The data indicate that prolactin has pleiotropic effects on homeostatic sensors of energy balance (ie, Cart) and physiological effectors (ie, kidney, BAT). We propose that prolactin release from the pituitary gland acts as an output signal of the hypothalamic rheostat controller to regulate adaptive changes in body mass.

Modeling blood metabolite homeostatic levels reduces sample heterogeneity across cohorts

Blood metabolite levels are affected by numerous factors, including preanalytical factors such as collection methods and geographical sites. These perturbations have caused deleterious consequences for many metabolomics studies and represent a major challenge in the metabolomics field. It is important to understand these factors and develop models to reduce their perturbations. However, to date, the lack of suitable mathematical models for blood metabolite levels under homeostasis has hindered progress. In this study, we develop quantitative models of blood metabolite levels in healthy adults based on multisite sample cohorts that mimic the current challenge. Five cohorts of samples obtained across four geographically distinct sites were investigated, focusing on approximately 50 metabolites that were quantified using 1H NMR spectroscopy. More than one-third of the variation in these metabolite profiles is due to cross-cohort variation. A dramatic reduction in the variation of metabolite levels (90%), especially their site-to-site variation (95%), was achieved by modeling each metabolite using demographic and clinical factors and especially other metabolites, as observed in the top principal components. The results also reveal that several metabolites contribute disproportionately to such variation, which could be explained by their association with biological pathways including biosynthesis and degradation. The study demonstrates an intriguing network effect of metabolites that can be utilized to better define homeostatic metabolite levels, which may have implications for improved health monitoring. As an example of the potential utility of the approach, we show that modeling gender-related metabolic differences retains the interesting variance while reducing unwanted (site-related) variance.

Development and Validation of a Fluorogenic Probe for Lysosomal Zinc Release

Zinc homeostasis, which allows optimal zinc utilization in diverse life processes, is responsible for the general well-being of human beings. This paper describes developing and validating an easily accessible indole-containing zinc-specific probe in the cellular milieu. The probe was synthesized from readily available starting materials and was subjected to steady-state fluorescence studies. It showed selective sensing behavior towards Zn2+ with reversible binding. The suppression of PET (Photoinduced Electron Transfer) and ESIPT (Excited State Intramolecular Proton Transfer) elicited selectivity, and the detection limit was 0.63 μM (LOQ 6.8 μM). The zinc sensing capability of the probe was also screened in the presence of low molecular weight ligands [LMWLs] and showed interference only with GSH and ATP. It is non-toxic and can detect zinc in different cell lines under various stress conditions such as inflammation, hyperglycemia, and apoptosis. The probe could stain the early and late stages of apoptosis in PAN-2 cells by monitoring the zinc release. Most experiments were conducted without external zinc supplementation, showing its innate ability to detect zinc.

TR(i)P Goes On: Auxiliary TRP Channel Subunits?

Transient receptor potential (TRP) cation channels are a diverse family of channels whose members play prominent roles as cellular sensors and effectors. The important role of TRP channels (and mechanosensitive piezo channels) in the complex interaction of our senses with the environment was underlined by the award of the Nobel Prize in Physiology or Medicine to 2 pioneers in this field, David Julius and Ardem Patapoutian. There are many competent and comprehensive reviews on many aspects of the TRP channels, and there is no intention to expand on them. Rather, after an introduction to the nomenclature, the molecular architecture of native TRP channel/protein complexes in vivo will be summarized using TRP channels of the canonical transient receptor potential subfamily as an example. This molecular architecture provides the basis for the signatures of native canonical transient receptor potential currents and their control by endogenous modulators and potential drugs.

Adipocyte p53 coordinates the response to intermittent fasting by regulating adipose tissue immune cell landscape

In obesity, sustained adipose tissue (AT) inflammation constitutes a cellular memory that limits the effectiveness of weight loss interventions. Yet, the impact of fasting regimens on the regulation of AT immune infiltration is still elusive. Here we show that intermittent fasting (IF) exacerbates the lipid-associated macrophage (LAM) inflammatory phenotype of visceral AT in obese mice. Importantly, this increase in LAM abundance is strongly p53 dependent and partly mediated by p53-driven adipocyte apoptosis. Adipocyte-specific deletion of p53 prevents LAM accumulation during IF, increases the catabolic state of adipocytes, and enhances systemic metabolic flexibility and insulin sensitivity. Finally, in cohorts of obese/diabetic patients, we describe a p53 polymorphism that links to efficacy of a fasting-mimicking diet and that the expression of p53 and TREM2 in AT negatively correlates with maintaining weight loss after bariatric surgery. Overall, our results demonstrate that p53 signalling in adipocytes dictates LAM accumulation in AT under IF and modulates fasting effectiveness in mice and humans.

Adipose Tissue Inflammation: Linking Physiological Stressors to Disease Susceptibility

The study of adipose tissue (AT) is enjoying a renaissance. White, brown, and beige adipocytes are being investigated in adult animals, and the critical roles of small depots like perivascular AT are becoming clear. But the most profound revision of the AT dogma has been its cellular composition and regulation. Single-cell transcriptomic studies revealed that adipocytes comprise well under 50% of the cells in white AT, and a substantial portion of the rest are immune cells. Altering the function of AT resident leukocytes can induce or correct metabolic syndrome and, more surprisingly, alter adaptive immune responses to infection. Although the field is dominated by obesity research, conditions such as rapid lipolysis, infection, and heat stress impact AT immune dynamics as well. Recent findings in rodents lead to critical questions that should be explored in domestic livestock as potential avenues for improved animal resilience to stressors, particularly as animals age.

Versatile Endogenous Editing of GluRIIA in Drosophila melanogaster

Glutamate receptors at the postsynaptic side translate neurotransmitter release from presynapses into postsynaptic excitation. They play a role in many forms of synaptic plasticity, e.g., homeostatic scaling of the receptor field, activity-dependent synaptic plasticity and the induction of presynaptic homeostatic potentiation (PHP). The latter process has been extensively studied at Drosophila melanogaster neuromuscular junctions (NMJs). The genetic removal of the glutamate receptor subunit IIA (GluRIIA) leads to an induction of PHP at the synapse. So far, mostly imprecise knockouts of the GluRIIA gene have been utilized. Furthermore, mutated and tagged versions of GluRIIA have been examined in the past, but most of these constructs were not expressed under endogenous regulatory control or involved the mentioned imprecise GluRIIA knockouts. We performed CRISPR/Cas9-assisted gene editing at the endogenous locus of GluRIIA. This enabled the investigation of the endogenous expression pattern of GluRIIA using tagged constructs with an EGFP and an ALFA tag for super-resolution immunofluorescence imaging, including structured illumination microscopy (SIM) and direct stochastic optical reconstruction microscopy (dSTORM). All GluRIIA constructs exhibited full functionality and PHP could be induced by philanthotoxin at control levels. By applying hierarchical clustering algorithms to analyze the dSTORM data, we detected postsynaptic receptor cluster areas of ~0.15 µm2. Consequently, our constructs are suitable for ultrastructural analyses of GluRIIA.

Protection against overfeeding-induced weight gain is preserved in obesity but does not require FGF21 or MC4R

Overfeeding triggers homeostatic compensatory mechanisms that counteract weight gain. Here, we show that both lean and diet-induced obese (DIO) male mice exhibit a potent and prolonged inhibition of voluntary food intake following overfeeding-induced weight gain. We reveal that FGF21 is dispensable for this defense against weight gain. Targeted proteomics unveiled novel circulating factors linked to overfeeding, including the protease  legumain (LGMN). Administration of recombinant LGMN lowers body weight and food intake in DIO mice. The protection against weight gain is also associated with reduced vascularization in the hypothalamus and sustained reductions in the expression of the orexigenic neuropeptide genes, Npy and Agrp, suggesting a role for hypothalamic signaling in this homeostatic recovery from overfeeding. Overfeeding of melanocortin 4 receptor (MC4R) KO mice shows that these mice can suppress voluntary food intake and counteract the enforced weight gain, although their rate of weight recovery is impaired. Collectively, these findings demonstrate that the defense against overfeeding-induced weight gain remains intact in obesity and involves mechanisms independent of both FGF21 and MC4R.

elegans

Copper (Cu) is an essential trace element, however an excess is toxic due to its redox properties. Cu homeostasis therefore needs to be tightly regulated via cellular transporters, storage proteins and exporters. An imbalance in Cu homeostasis has been associated with neurodegenerative disorders such as Wilson's disease, but also Alzheimer's or Parkinson's disease. In our current study, we explored the utility of using Caenorhabditis elegans (C. elegans) as a model of Cu dyshomeostasis. The application of excess Cu dosing and the use of mutants lacking the intracellular Cu chaperone atox-1 and major Cu storage protein ceruloplasmin facilitated the assessment of Cu status, functional markers including total Cu levels, labile Cu levels, Cu distribution and the gene expression of homeostasis-related genes. Our data revealed a decrease in total Cu uptake but an increase in labile Cu levels due to genetic dysfunction, as well as altered gene expression levels of Cu homeostasis-associated genes. In addition, the data uncovered the role ceruloplasmin and atox-1 play in the worm's Cu homeostasis. This study provides insights into suitable functional Cu markers and Cu homeostasis in C. elegans, with a focus on labile Cu levels, a promising marker of Cu dysregulation during disease progression.

Vitamin K2 protects mice against non-alcoholic fatty liver disease induced by high-fat diet

Non-alcoholic fatty liver disease (NAFLD) is one of the most common liver diseases worldwide and there is a huge unmet need to find safer and more effective drugs. Vitamin K has been found to regulate lipid metabolism in the liver. However, the effects of vitamin K2 on NAFLD is unclear. This study aims to evaluate the preventive and therapeutic effects of vitamin K2 in the process of fatty liver formation and to explore molecular mechanisms the associated with lipid metabolism. A non-alcoholic fatty liver model was established by high-fat diet administration for three months. Vitamin K2 significantly reduced the body weight, abdominal circumference and body fat percentage of NAFLD mice. Vitamin K2 also showed histological benefits in reducing hepatic steatosis. NAFLD mice induced by high-fat diet showed increased HMGR while vitamin K2 intervention could reverse the pathological lterations. Adiponectin (APN) is an endogenous bioactive polypeptide or protein secreted by adipocytes. We detected APN, SOD, AlaDH and other indicators that may affect the state of high-fat diet mice, but the experimental results showed that the above indicators did not change significantly. It is worth noting that the effect of vitamin K2 supplementation on the lipid-lowering effect of uc OC in vivo needs to be further explored. This study first reported the protective effect of vitamin K2 on high-fat diet-induced NAFLD in mice. The protective effect of vitamin K2 may be related to the improvement of lipid metabolism disorder in NAFLD.

Aneuploidy-induced cellular behaviors: Insights from Drosophila

A balanced gene complement is crucial for proper cell function. Aneuploidy, the condition of having an imbalanced chromosome set, alters the stoichiometry of gene copy numbers and protein complexes and has dramatic consequences at the cellular and organismal levels. In humans, aneuploidy is associated with different pathological conditions including cancer, microcephaly, mental retardation, miscarriages, and aging. Over the last century, Drosophila has provided a valuable system for studying the consequences of systemic aneuploidies. More recently, it has contributed to the identification and molecular dissection of aneuploidy-induced cellular behaviors and their impact at the tissue and organismal levels. In this perspective, we review this active field of research, first by comparing knowledge from yeast, mouse, and human cells, then by highlighting the contributions of Drosophila. The aim of these discussions was to further our understanding of the functional interplay between aneuploidy, cell physiology, and tissue homeostasis in human development and disease.

The preoptic area and dorsal habenula jointly support homeostatic navigation in larval zebrafish

Animals must maintain physiological processes within an optimal temperature range despite changes in their environment. Through behavioral assays, whole-brain functional imaging, and neural ablations, we show that larval zebrafish, an ectothermic vertebrate, achieves thermoregulation through homeostatic navigation-non-directional and directional movements toward the temperature closest to its physiological setpoint. A brain-wide circuit encompassing several brain regions enables this behavior. We identified the preoptic area of the hypothalamus (PoA) as a key brain structure in triggering non-directional reorientation when thermal conditions are worsening. This result shows an evolutionary conserved role of the PoA as principal thermoregulator of the brain also in ectotherms. We further show that the habenula (Hb)-interpeduncular nucleus (IPN) circuit retains a short-term memory of the sensory history to support the generation of coherent directed movements even in the absence of continuous sensory cues. We finally provide evidence that this circuit may not be exclusive for temperature but may convey a more abstract representation of relative valence of physiologically meaningful stimuli regardless of their specific identity to enable homeostatic navigation.

Secretin-dependent signals in the ventromedial hypothalamus regulate energy metabolism and bone homeostasis in mice

Secretin, though originally discovered as a gut-derived hormone, is recently found to be abundantly expressed in the ventromedial hypothalamus, from which the central neural system controls satiety, energy metabolism, and bone homeostasis. However, the functional significance of secretin in the ventromedial hypothalamus remains unclear. Here we show that the loss of ventromedial hypothalamus-derived secretin leads to osteopenia in male and female mice, which is primarily induced by diminished cAMP response element-binding protein phosphorylation and upregulation in peripheral sympathetic activity. Moreover, the ventromedial hypothalamus-secretin inhibition also contributes to hyperphagia, dysregulated lipogenesis, and impaired thermogenesis, resulting in obesity in male and female mice. Conversely, overexpression of secretin in the ventromedial hypothalamus promotes bone mass accrual in mice of both sexes. Collectively, our findings identify an unappreciated secretin signaling in the central neural system for the regulation of energy and bone metabolism, which may serve as a new target for the clinical management of obesity and osteoporosis.

Dynamic changes of endothelial and stromal cilia are required for the maintenance of corneal homeostasis

Primary cilia are distributed extensively within the corneal epithelium and endothelium. However, the presence of cilia in the corneal stroma and the dynamic changes and roles of endothelial and stromal cilia in corneal homeostasis remain largely unknown. Here, we present compelling evidence for the presence of primary cilia in the corneal stroma, both in vivo and in vitro. We also demonstrate dynamic changes of both endothelial and stromal cilia during corneal development. In addition, our data show that cryoinjury triggers dramatic cilium formation in the corneal endothelium and stroma. Furthermore, depletion of cilia in mutant mice lacking intraflagellar transport protein 88 compromises the corneal endothelial capacity to establish the effective tissue barrier, leading to an upregulation of α-smooth muscle actin within the corneal stroma in response to cryoinjury. These observations underscore the essential involvement of corneal endothelial and stromal cilia in maintaining corneal homeostasis and provide an innovative strategy for the treatment of corneal injuries and diseases.

Role of type-I and type-III interferons in gastrointestinal homeostasis and pathogenesis

Interferon (IFN) was discovered based on interference with virus production, and three types of IFN are now defined. Since its discovery, IFN's roles have expanded beyond viruses to diverse pathogen types, tissue homeostasis, and inflammatory disease. The gastrointestinal (GI) tract is arguably the tissue where the roles of IFN types are most distinct, with a particularly prominent role for type-III IFN in antiviral protection of the intestinal epithelium. Current studies continue to deepen our understanding of the type- and tissue-specific roles of IFN. This review highlights these advances within the GI tract, including discovery of protective roles for type-III IFNs against nonviral GI pathogens, and discovery of an antiviral homeostatic type-III IFN response within the intestinal epithelium.

Ketocarotenoid production in tomato triggers metabolic reprogramming and cellular adaptation: The quest for homeostasis

Plants are sessile and therefore have developed an extraordinary capacity to adapt to external signals. Here, the focus is on the plasticity of the plant cell to respond to new intracellular cues. Ketocarotenoids are high-value natural red pigments with potent antioxidant activity. In the present study, system-level analyses have revealed that the heterologous biosynthesis of ketocarotenoids in tomato initiated a series of cellular and metabolic mechanisms to cope with the formation of metabolites that are non-endogenous to the plant. The broad multilevel changes were linked to, among others, (i) the remodelling of the plastidial membrane, where the synthesis and storage of ketocarotenoids occurs; (ii) the recruiting of core metabolic pathways for the generation of metabolite precursors and energy; and (iii) redox control. The involvement of the metabolites as regulators of cellular processes shown here reinforces their pivotal role suggested in the remodelled 'central dogma' concept. Furthermore, the role of metabolic reprogramming to ensure cellular homeostasis is proposed.

A Multi-center Trial Evaluating a Serum Comprised of Plant-based Adaptogens Targeting Skin Quality

Objective

The ability of the skin to maintain homeostasis declines with age. Adaptogens support the capacity of the skin to respond to stress. We sought to evaluate the efficacy of a novel serum comprised of plant-based adaptogens for improving photoaged skin following twice-daily application.

Methods

A multi-center, 12-week trial was conducted in participants aged 45 to 65 years, Fitzpatrick Skin Type (FST) I to VI, with mild-to-severe photoaging based on a 10-point grading scale (3 [Minimum] to 7 [Maximum]). Visible improvements were assessed in erythema, pore size, skin dullness, skin texture, and uneven pigmentation utilizing a six-point grading scale (0=None to 5=Severe). Global skin quality was measured utilizing our Global Skin Quality Index (GSQI). Sebum measurements were obtained in a subset of participants. Patient satisfaction and tolerability were recorded throughout the study.

Results

Fifty-three participants were enrolled and completed the study. Mean age was 56 years and 66 percent were White, 17 percent were Black, 8 percent were Hispanic, 6 percent were Asian/Pacific Islander, and 81 percent had moderate photodamage. At Week 12, significant mean percent improvements from baseline were demonstrated in erythema (50%), dullness (44%), texture (52%), pore size (23%), and uneven pigmentation (21%; all p<.0001). Significant GSQI improvements from baseline were observed at Week 12 (39%; p<0.0001). Significant mean reductions from baseline in skin surface sebum were demonstrated at Week 12 (-38%; p<0.0001). All adverse events (AEs) were mild and transient.

Conclusion

A novel serum comprised of plant-based adaptogens, demonstrated improvements from baseline in the appearance of erythema, dullness, texture, pore size, uneven pigmentation, and global skin quality over 12 weeks. Participants reported high levels of satisfaction, with mild, transient AEs reported.