Regulation of neuropeptide Y in body microenvironments and its potential application in therapies: a review

A new invertebrate NPY-like polypeptide, ZoaNPY, from the Zoanthus sociatus, as a novel ligand of human NPY Y2 receptor rescues vascular insufficiency via PLC/PKC and Src- FAK-dependent signaling pathways

Our recent multi-omics studies have revealed rich sources of novel bioactive proteins and polypeptides from marine organisms including cnidarians. In the present study, we initially conducted a transcriptomic analysis to review the composition profile of polypeptides from Zoanthus sociatus. Then, a newly discovered NPY-like polypeptide-ZoaNPY was selected for further in silico structural, binding and virtually pharmacological studies. To evaluate the pro-angiogenic effects of ZoaNPY, we employed an in vitro HUVECs model and an in vivo zebrafish model. Our results indicate that ZoaNPY, at 1-100 pmol, enhances cell survival, migration and tube formation in the endothelial cells. Besides, treatment with ZoaNPY could restore a chemically-induced vascular insufficiency in zebrafish embryos. Western blot results demonstrated the application of ZoaNPY could increase the phosphorylation of proteins related to angiogenesis signaling including PKC, PLC, FAK, Src, Akt, mTOR, MEK, and ERK1/2. Furthermore, through molecular docking and surface plasmon resonance (SPR) verification, ZoaNPY was shown to directly and physically interact with NPY Y2 receptor. In view of this, all evidence showed that the pro-angiogenic effects of ZoaNPY involve the activation of NPY Y2 receptor, thereby activating the Akt/mTOR, PLC/PKC, ERK/MEK and Src- FAK-dependent signaling pathways. Furthermore, in an excision wound model, the treatment with ZoaNPY was shown to accelerate the wound healing process in mice. Our findings provide new insights into the discovery and development of novel pro-angiogenic drugs derived from NPY-like polypeptides in the future.

The role of NPY signaling pathway in diagnosis, prognosis and treatment of stroke

Neuropeptide Y (NPY), an extensively distributed neurotransmitter within the central nervous system (CNS), was initially detected and isolated from the brain of a pig in 1982. By binding to its G protein-coupled receptors, NPY regulates immune responses and contributes to the pathogenesis of numerous inflammatory diseases. The hippocampus contained the maximum concentration in the CNS, with the cerebral cortex, hypothalamus, thalamus, brainstem, and cerebellum following suit. This arrangement suggests that the substance has a specific function within the CNS. More and more studies have shown that NPY is involved in the physiological and pathological mechanism of stroke, and its serum concentration can be one of the specific biomarkers of stroke and related complications because of its high activity, broad and complex effects. By summarizing relevant literature, this article aims to gain a thorough understanding of the potential clinical applications of NPY in the treatment of stroke, identification of stroke and its related complications, and assessment of prognosis.

Investigation of crocin's protective effect on cyclophosphamide-induced hypothalamic-pituitary-gonadal axis defects in adult female rats

Cyclophosphamide is a drug used in chemotherapy. However, it has side effects, including changes in reproductive system functioning. Some herbal compounds can reduce the harmful effects of cyclophosphamide. This study aims to investigate the protective role of crocin against changes caused by Cyclophosphamide in ovarian tissue through changes in the expression of genes involved in the hypothalamic-pituitary-gonadal axis. This experimental study was performed on 24 adult female Wistar rats. Mice were divided into four groups (normal saline, 30 mg/kg cyclophosphamide, 100 mg/kg crocin and 30 mg/kg cyclophosphamide, and 200 mg/kg crocin and 30 mg/kg cyclophosphamide). At the end of the treatment period, the hypothalamus and ovaries were also removed to evaluate ob-Rb, ob-Ra, and NPY genes expression using real-time PCR and histological changes in the ovaries. Data were analyzed by SPSS statistical software. The expression of genes, number of follicles, and follicle diameter significantly decreased in the cyclophosphamide-treated groups compared with the control group. In the crocin and cyclophosphamide-treated groups, drug-induced reproductive complications were mitigated. The current findings indicate that by increasing the expression of genes ob-Rb, ob-Ra, and NPY, crocin could modulate the harmful effects of cyclophosphamide.

Neuropeptide Y-Mediated Gut Microbiota Alterations Aggravate Postmenopausal Osteoporosis

Postmenopausal osteoporosis (PMO) is often accompanied by neuroendocrine changes in the hypothalamus, which closely associates with the microbial diversity, community composition, and intestinal metabolites of gut microbiota (GM). With the emerging role of GM in bone metabolism, a potential neuroendocrine signal neuropeptide Y (NPY) mediated brain-gut-bone axis has come to light. Herein, it is reported that exogenous overexpression of NPY reduced bone formation, damaged bone microstructure, and up-regulated the expressions of pyroptosis-related proteins in subchondral cancellous bone in ovariectomized (OVX) rats, but Y1 receptor antagonist (Y1Ra) reversed these changes. In addition, it is found that exogenous overexpression of NPY aggravated colonic inflammation, impaired intestinal barrier integrity, enhanced intestinal permeability, and increased serum lipopolysaccharide (LPS) in OVX rats, and Y1Ra also reversed these changes. Most importantly, NPY and Y1Ra modulated the microbial diversity and changed the community composition of GM in OVX rats, and thereby affecting the metabolites of GM (e.g., LPS) entering the blood circulation. Moreover, fecal microbiota transplantation further testified the effect of NPY-mediated GM changes on bone. In vitro, LPS induced pyroptosis, reduced viability, and inhibited differentiation of osteoblasts. The study demonstrated the existence of NPY-mediated brain-gut-bone axis and it might be a novel emerging target to treat PMO.

Neuropeptide Y and its receptors in prostate cancer: associations with cancer invasiveness and perineural spread

PURPOSE

Neuropeptide Y (NPY) is a pleiotropic peptide, which is involved in many biological mechanisms important in regulation of cell growth and survival. The aim of this study was a comprehensive analysis of the NPY system in prostate pathology.

METHODS

The study was based on immunohistochemical analysis of NPY and its receptors, Y1R, Y2R and Y5R, in tissue samples from benign prostate (BP), primary prostate cancer (PCa) and PCa bone metastases. Tissue microarray (TMA) technique was employed, with analysis of multiple cores from each specimen. Intensity of the immunoreactivity and expression index (EI), as well as distribution of the immunostaining in neoplastic cells and stromal elements were evaluated. Perineural invasion (PNI) and extraprostatic extension (EPE) were areas of special interests. Moreover, a transwell migration assay on the LNCaP PCa cell line was used to assess the chemotactic properties of NPY.

RESULTS

Morphological analysis revealed homogeneous membrane and cytoplasmic pattern of NPY staining in cancer cells and its membrane localization with apical accentuation in BP glands. All elements of the NPY system were upregulated in pre-invasive prostate intraepithelial neoplasia, PCa and metastases. EI and staining intensity of NPY receptors were significantly higher in PCa then in BP with correlation between Y2R and Y5R. The strength of expression of the NPY system was further increased in the PNI and EPE areas. In bone metastases, Y1R and Y5R presented high expression scores.

CONCLUSION

The results of our study suggest that the NPY system is involved in PCa, starting from early stages of its development to disseminated states of the disease, and participates in the invasion of PCa into the auto and paracrine matter.

Nociceptor-Macrophage Interactions in Apical Periodontitis: How Biomolecules Link Inflammation with Pain

Periradicular tissues have a rich supply of peripheral afferent neurons, also known as nociceptive neurons, originating from the trigeminal nerve. While their primary function is to relay pain signals to the brain, these are known to be involved in modulating innate and adaptive immunity by initiating neurogenic inflammation (NI). Studies have investigated neuroanatomy and measured the levels of biomolecules such as cytokines and neuropeptides in human saliva, gingival crevicular fluid, or blood/serum samples in apical periodontitis (AP) to validate the possible role of trigeminal nociceptors in inflammation and tissue regeneration. However, the contributions of nociceptors and the mechanisms involved in the neuro-immune interactions in AP are not fully understood. This narrative review addresses the complex biomolecular interactions of trigeminal nociceptors with macrophages, the effector cells of the innate immune system, in the clinical manifestations of AP.

Dynamics of the Second Extracellular Loop Control Transducer Coupling of Peptide-Activated GPCRs

Many peptide-activated rhodopsin-like GPCRs share a β-hairpin folding motif in the extracellular loop 2 (ECL2), which interacts with the peptide ligand while at the same time being connected to transmembrane helix 3 (TM3) via a highly conserved disulfide bond. Currently, it remains unknown whether the coupling of the specifically shaped ECL2 to TM3 influences the activation of peptide-activated GPCRs. We investigated this possibility in a selection of peptide GPCRs with known structures. Most of the receptors with cysteine to alanine mutations folded like the respective wild-type and resided in the cell membrane, challenging pure folding stabilization by the disulfide bridge. G-protein signaling of the disulfide mutants was retained to a greater extent in secretin-like GPCRs than in rhodopsin-like GPCRs, while recruitment of arrestin was completely abolished in both groups, which may be linked to alterations in ligand residence time. We found a correlation between receptor activity of the neuropeptide Y2 receptor and alterations in ECL2 dynamics using engineered disulfide bridges or site-directed spin labeling and EPR spectroscopy. These data highlight the functional importance of the TM3-ECL2 link for the activation of specific signaling pathways in peptide-activated GPCRs, which might have implications for future drug discovery.

RNA-Seq Reveals Sex Differences in Gene Expression during Peripheral Neuropathic Inflammation and in Pain Relief from a COX-2 Inhibiting Theranostic Nanoemulsion

Given decades of neuroinflammatory pain research focused only on males, there is an urgent need to better understand neuroinflammatory pain in females. This, paired with the fact that currently there is no long-term effective treatment for neuropathic pain furthers the need to evaluate how neuropathic pain develops in both sexes and how it can be relieved. Here we show that chronic constriction injury of the sciatic nerve caused comparable levels of mechanical allodynia in both sexes. Using a COX-2 inhibiting theranostic nanoemulsion with increased drug loading, both sexes achieved similar reduction in mechanical hypersensitivity. Given that both sexes have improved pain behavior, we specifically explored differential gene expression between sexes in the dorsal root ganglia (DRG) during pain and relief. Total RNA from the DRG revealed a sexually dimorphic expression for injury and relief caused by COX-2 inhibition. Of note, both males and females experience increased expression of activating transcription factor 3 (Atf3), however, only the female DRG shows decreased expression following drug treatment. Alternatively, S100A8 and S100A9 expression appear to play a sex specific role in relief in males. The sex differences in RNA expression reveal that comparable behavior does not necessitate the same gene expression.

Role and mechanism of fibroblast-activated protein-α expression on the surface of fibroblast-like synoviocytes in rheumatoid arthritis

Fibroblast-activated protein-α (FAP) is a type II integrated serine protease expressed by activated fibroblasts during fibrosis or inflammation. Fibroblast-like synoviocytes (FLSs) in rheumatoid arthritis (RA) synovial sites abundantly and stably overexpress FAP and play important roles in regulating the cellular immune, inflammatory, invasion, migration, proliferation, and angiogenesis responses in the synovial region. Overexpression of FAP is regulated by the initial inflammatory microenvironment of the disease and epigenetic signaling, which promotes RA development by regulating FLSs or affecting the signaling cross-linking FLSs with other cells at the local synovium and inflammatory stimulation. At present, several treatment options targeting FAP are in the process of development. This review discusses the basic features of FAP expressed on the surface of FLSs and its role in RA pathophysiology and advances in targeted therapies.

Peptidome and Transcriptome Analysis of Plant Peptides Involved in Bipolaris maydis Infection of Maize

Southern corn leaf blight (SCLB) caused by Bipolaris maydis threatens maize growth and yield worldwide. In this study, TMT-labeled comparative peptidomic analysis was established between infected and uninfected maize leaf samples using liquid-chromatography-coupled tandem mass spectrometry. The results were further compared and integrated with transcriptome data under the same experimental conditions. Plant peptidomic analysis identified 455 and 502 differentially expressed peptides (DEPs) in infected maize leaves on day 1 and day 5, respectively. A total of 262 common DEPs were identified in both cases. Bioinformatic analysis indicated that the precursor proteins of DEPs are associated with many pathways generated by SCLB-induced pathological changes. The expression profiles of plant peptides and genes in maize plants were considerably altered after B. maydis infection. These findings provide new insights into the molecular mechanisms of SCLB pathogenesis and offer a basis for the development of maize genotypes with SCLB resistance.

Molecular and Cellular Crosstalk between Bone and Brain: Accessing Bidirectional Neural and Musculoskeletal Signaling during Aging and Disease

Molecular omics technologies, including proteomics, have enabled the elucidation of key signaling pathways that mediate bidirectional communication between the brain and bone tissues. Here we provide a brief summary of the clinical and molecular evidence of the need to study the bone-brain axis of cross-tissue cellular communication. Clear clinical and molecular evidence suggests biological interactions and similarities between bone and brain cells. Here we review the current mass spectrometric techniques for studying brain and bone diseases with an emphasis on neurodegenerative diseases and osteoarthritis/osteoporosis, respectively. Further study of the bone-brain axis on a molecular level and evaluation of the role of proteins, neuropeptides, osteokines, and hormones in molecular pathways linked to bone and brain diseases is critically needed. The use of mass spectrometry and other omics technologies to analyze these cross-tissue signaling events and interactions will help us better understand disease progression and comorbidities and potentially identify new pathways and targets for therapeutic interventions. Proteomic measurements are particularly favorable for investigating the role of signaling and secreted and circulating analytes and identifying molecular and metabolic pathways implicated in age-related diseases.

Neuropeptide Y protects kidney from acute kidney injury by inactivating M1 macrophages via the Y1R-NF-κB-Mincle-dependent mechanism

Neuropeptide Y (NPY) is produced by the nerve system and may contribute to the progression of CKD. The present study found the new protective role for NPY in AKI in both patients and animal models. Interestingly, NPY was constitutively expressed in blood and resident kidney macrophages by co-expressing NPY and CD68+ markers, which was lost in patients and mice with AKI-induced by cisplatin. Unexpectedly, NPY was renoprotective in AKI as mice lacking NPY developed worse renal necroinflammation and renal dysfunction in cisplatin and ischemic-induced AKI. Importantly, NPY was also a therapeutic agent for AKI because treatment with exogenous NPY dose-dependently inhibited cisplatin-induced AKI. Mechanistically, NPY protected kidney from AKI by inactivating M1 macrophages via the Y1R-NF-κB-Mincle-dependent mechanism as deleting or silencing NPY decreased Y1R but increased NF-κB-Mincle-mediated M1macrophage activation and renal necroinflammation, which were reversed by addition of NPY or by silencing Mincle but promoted by blocking Y1R with BIBP 3226. Thus, NPY is renoprotective and may be a novel therapeutic agent for AKI. NPY may act via Y1R to protect kidney from AKI by blocking NF-κB-Mincle-mediated M1 macrophage activation and renal necroinflammation.

Bonding of Neuropeptide Y on Graphene Oxide for Drug Delivery Applications to the Central Nervous System

Nanoscale graphene-based materials (GBMs) enable targeting subcellular structures of the nervous system, a feature crucial for the successful engineering of alternative nanocarriers to deliver drugs and to treat neurodisorders. Among GBMs, graphene oxide (GO) nanoflakes, showing good dispersibility in water solution and being rich of functionalizable oxygen groups, are ideal core structures for carrying biological active molecules to the brain, such as the neuropeptide Y (NPY). In addition, when unconjugated, these nanomaterials have been reported to modulate neuronal function per se. Although some GBM-based nanocarriers have been tested both in vitro and in vivo, a thorough characterization of covalent binding impact on the biological properties of the carried molecule and/or of the nanomaterial is still missing. Here, a copper(I)-catalyzed alkyne-azide cycloaddition strategy was employed to synthesize the GO-NPY complex. By investigating through electrophysiology the impact of these conjugates on the activity of hippocampal neurons, we show that the covalent modification of the nanomaterial, while making GO an inert platform for the vectorized delivery, enhances the duration of NPY pharmacological activity. These findings support the future use of GO for the development of smart platforms for nervous system drug delivery.

Neuroprotective Effects of Neuropeptide Y on Human Neuroblastoma SH-SY5Y Cells in Glutamate Excitotoxicity and ER Stress Conditions

Neuropeptide Y (NPY), a sympathetic neurotransmitter, is involved in various physiological functions, and its dysregulation is implicated in several neurodegenerative diseases. Glutamate excitotoxicity, endoplasmic reticulum (ER) stress, and oxidative stress are the common mechanisms associated with numerous neurodegenerative illnesses. The present study aimed to elucidate the protective effects of NPY against glutamate toxicity and tunicamycin-induced ER stress in the human neuroblastoma SH-SY5Y cell line. We exposed the SH-SY5Y cells to glutamate and tunicamycin for two different time points and analyzed the protective effects of NPY at different concentrations. The protective effects of NPY treatments were assessed by cell viability assay, and the signalling pathway changes were evaluated by biochemical techniques such as Western blotting and immunofluorescence assays. Our results showed that treatment of SH-SY5Y cells with NPY significantly increased the viability of the cells in both glutamate toxicity and ER stress conditions. NPY treatments significantly attenuated the glutamate-induced pro-apoptotic activation of ERK1/2 and JNK/BAD pathways. The protective effects of NPY were further evident against tunicamycin-induced ER stress. NPY treatments significantly suppressed the ER stress activation by downregulating BiP, phospho-eIF2α, and CHOP expression. In addition, NPY alleviated the Akt/FoxO3a pathway in acute oxidative conditions caused by glutamate and tunicamycin in SH-SY5Y cells. Our results demonstrated that NPY is neuroprotective against glutamate-induced cell toxicity and tunicamycin-induced ER stress through anti-apoptotic actions.

Psychological and Physiological Changes during Basic, Underwater, Demolition/SEAL Training

This longitudinal study examines the growth of psychological characteristics and adaptation of physiological markers of stress during a six-month assessment and selection course for U.S. Navy SEALs. Resilience, hardiness, and grit instruments were used to evaluate the psychological characteristics. Blood samples were taken to determine physiological markers related to stress adaptation; specifically, evaluating DHEA, DHEA-to-cortisol ratio, BDNF, NPY, and cortisol. Data was collected at four timepoints throughout the assessment and selection course from 353 students over three classes. Results indicated that resilience and hardiness grow after an initial decline, DHEA and DHEA-to-cortisol increased suggesting physiological adaptation. However, psychological and physiological markers do not exhibit the same growth patterns for participants in the course. This study enhances the understanding of psychological growth and physiological adaptation in a high-stress environment over an extended duration.

Neuropeptides in Cancer: Friend and Foe?

Neuropeptides are small regulatory molecules found throughout the body, most notably in the nervous, cardiovascular, and gastrointestinal systems. They serve as neurotransmitters or hormones in the regulation of diverse physiological processes. Cancer cells escape normal growth control mechanisms by altering their expression of growth factors, receptors, or intracellular signals, and neuropeptides have recently been recognized as mitogens in cancer growth and development. Many neuropeptides and their receptors exist in multiple subtypes, coupling with different downstream signaling pathways and playing distinct roles in cancer progression. The consideration of neuropeptide/receptor systems as anticancer targets is already leading to new biological and diagnostic knowledge that has the potential to enhance the understanding and treatment of cancer. In this review, recent discoveries regarding neuropeptides in a wide range of cancers, emphasizing their mechanisms of action, signaling cascades, regulation, and therapeutic potential, are discussed. Current technologies used to manipulate and analyze neuropeptides/receptors are described. Applications of neuropeptide analogs and their receptor inhibitors in translational studies and radio-oncology are rapidly increasing, and the possibility for their integration into therapeutic trials and clinical treatment appears promising.

Neurotransmitters: Potential Targets in Glioblastoma

Simple Summary

Aiming to discover potential treatments for GBM, this review connects emerging research on the roles of neurotransmitters in the normal neural and the GBM microenvironments and sheds light on the prospects of their application in the neuropharmacology of GBM. Conventional therapy is blamed for its poor effect, especially in inhibiting tumor recurrence and invasion. Facing this dilemma, we focus on neurotransmitters that modulate GBM initiation, progression and invasion, hoping to provide novel therapy targeting GBM. By analyzing research concerning GBM therapy systematically and scientifically, we discover increasing insights into the regulatory effects of neurotransmitters, some of which have already shown great potential in research in vivo or in vitro. After that, we further summarize the potential drugs in correlation with previously published research. In summary, it is worth expecting that targeting neurotransmitters could be a promising novel pharmacological approach for GBM treatment.

Abstract

For decades, glioblastoma multiforme (GBM), a type of the most lethal brain tumor, has remained a formidable challenge in terms of its treatment. Recently, many novel discoveries have underlined the regulatory roles of neurotransmitters in the microenvironment both physiologically and pathologically. By targeting the receptors synaptically or non-synaptically, neurotransmitters activate multiple signaling pathways. Significantly, many ligands acting on neurotransmitter receptors have shown great potential for inhibiting GBM growth and development, requiring further research. Here, we provide an overview of the most novel advances concerning the role of neurotransmitters in the normal neural and the GBM microenvironments, and discuss potential targeted drugs used for GBM treatment.

Immunomodulatory Role of Neuropeptides in the Cornea

The transparency of the cornea along with its dense sensory innervation and resident leukocyte populations make it an ideal tissue to study interactions between the nervous and immune systems. The cornea is the most densely innervated tissue of the body and possesses both immune and vascular privilege, in part due to its unique repertoire of resident immune cells. Corneal nerves produce various neuropeptides that have a wide range of functions on immune cells. As research in this area expands, further insights are made into the role of neuropeptides and their immunomodulatory functions in the healthy and diseased cornea. Much remains to be known regarding the details of neuropeptide signaling and how it contributes to pathophysiology, which is likely due to complex interactions among neuropeptides, receptor isoform-specific signaling events, and the inflammatory microenvironment in disease. However, progress in this area has led to an increase in studies that have begun modulating neuropeptide activity for the treatment of corneal diseases with promising results, necessitating the need for a comprehensive review of the literature. This review focuses on the role of neuropeptides in maintaining the homeostasis of the ocular surface, alterations in disease settings, and the possible therapeutic potential of targeting these systems.

Bisphenol A (BPA) Leading to Obesity and Cardiovascular Complications: A Compilation of Current In Vivo Study

BPA is one of the most common endocrine disruptors that is widely being manufactured daily nationwide. Although scientific evidence supports claims of negative effects of BPA on humans, there is also evidence suggesting that a low level of BPA is safe. However, numerous in vivo trials contraindicate with this claim and there is a high possibility of BPA exposure could lead to obesity. It has been speculated that this does not stop with the exposed subjects only, but may also cause transgenerational effects. Direct disruption of endocrine regulation, neuroimmune and signaling pathways, as well as gut microbiata, has been identified to be interrupted by BPA exposure, leading to overweight or obesity. In these instances, cardiovascular complications are one of the primary notable clinical signs. In regard to this claim, this review paper discusses the role of BPA on obesity in the perspective of endocrine disruptions and possible cardiovascular complications that may arise due to BPA. Thus, the aim of this review is to outline the changes in gut microbiota and neuroimmune or signaling mechanisms involved in obesity in relation to BPA. To identify potentially relevant articles, a depth search was done on the databases Nature, PubMed, Wiley Online Library, and Medline & Ovid from the past 5 years. According to Boolean operator guideline, selected keywords such as (1) BPA OR environmental chemical AND fat OR LDL OR obese AND transgenerational effects or phenocopy (2) Endocrine disruptors OR chemical AND lipodystrophy AND phenocopy (3) Lipid profile OR weight changes AND cardiovascular effect (4) BPA AND neuroimmune OR gene signaling, were used as search terms. Upon screening, 11 articles were finalized to be further reviewed and data extraction tables containing information on (1) the type of animal model (2) duration and dosage of BPA exposure (3) changes in the lipid profile or weight (4) genes, signaling mechanism, or any neuroimmune signal involved, and (5) transgenerational effects were created. In toto, the study indicates there are high chances of BPA exposure affecting lipid profile and gene associated with lipolysis, leading to obesity. Therefore, this scoping review recapitulates the possible effects of BPA that may lead to obesity with the evidence of current in vivo trials. The biomarkers, safety concerns, recommended dosage, and the impact of COVID-19 on BPA are also briefly described.

Wearable electrochemical biosensors to measure biomarkers with complex blood-to-sweat partition such as proteins and hormones

Smart electronic devices based on micro-controllers, also referred to as fashion electronics, have raised wearable technology. These devices may process physiological information to facilitate the wearer's immediate biofeedback in close contact with the body surface. Standard market wearable devices detect observable features as gestures or skin conductivity. In contrast, the technology based on electrochemical biosensors requires a biomarker in close contact with both a biorecognition element and an electrode surface, where electron transfer phenomena occur. The noninvasiveness is pivotal for wearable technology; thus, one of the most common target tissues for real-time monitoring is the skin. Noninvasive biosensors formats may not be available for all analytes, such as several proteins and hormones, especially when devices are installed cutaneously to measure in the sweat. Processes like cutaneous transcytosis, the paracellular cell–cell unions, or even reuptake highly regulate the solutes content of the sweat. This review discusses recent advances on wearable devices based on electrochemical biosensors for biomarkers with a complex blood-to-sweat partition like proteins and some hormones, considering the commented release regulation mechanisms to the sweat. It highlights the challenges of wearable epidermal biosensors (WEBs) design and the possible solutions. Finally, it charts the path of future developments in the WEBs arena in converging/emerging digital technologies.