Tissue Environment Research Articles

An injectable, self-healable, and antimicrobial hydroxypropyl chitosan/poly(vinyl alcohol) hydrogel for drug delivery systems

Periodontitis is a chronic inflammatory disease caused by bacteria, and topical medication is the most efficient way to treat it. Injectable hydrogels have been used in the treatment of periodontitis because of their injectability, excellent biocompatibility, and controlled drug-release properties. However, conventional injectable hydrogels lack self-healing properties or have weak mechanical properties, which render them unable to adapt to the intricate oral environment of periodontal tissues. Therefore, a double cross-linked network hydrogel was prepared in this study using poly(vinyl alcohol) and hydroxypropyl chitosan as substrates, and the properties of the hydrogels were evaluated by altering the concentration of poly(vinyl alcohol). Experimental evidence indicates that the hydrogels showed excellent biocompatibility, degradation performances, slow-release properties of the drug (168 h), and significant antibacterial efficacy against E. coli (86.18 %) and S. aureus (85.69 %). Additionally, the hydrogel exhibited favorable mechanical properties (18.20 KPa), self-healing capabilities, and injectability because of the synergistic interaction of multiple dynamic covalent bonds, which allowed it to adapt to the complex therapeutic conditions of the oral cavity. These excellent properties suggest that the hydrogel has the potential to be used as a drug carrier for periodontitis treatment.

Reversing Pdgfrβ Signaling Restores Metabolically Active Beige Adipocytes by Alleviating ILC2 Suppression in Aged and Obese Mice.

Platelet Derived Growth Factor Receptor Beta (Pdgfrβ) suppresses the formation of cold temperature-induced beige adipocytes in aged mammals. We aimed to determine if deleting Pdgfrβ in aged mice could rejuvenate metabolically active beige adipocytes by activating group 2 innate lymphoid cells (ILC2), and whether this effect could counteract diet-induced obesity-associated beige fat decline. We employed Pdgfrβ gain-of-function and loss-of-function mouse models targeting beige adipocyte progenitor cells (APCs). Our approach included cold exposure, metabolic cage analysis, and age and diet-induced obesity models to examine beige fat development and metabolic function under varied Pdgfrβ activity. Acute cold exposure alone enhanced metabolic benefits in aged mice, irrespective of beige fat generation. However, Pdgfrβ deletion in aged mice reestablished the formation of metabolically functional beige adipocytes, enhancing metabolism. Conversely, constitutive Pdgfrβ activation in young mice stymied beige fat development. Mechanistically, Pdgfrβ deletion upregulated IL-33, promoting ILC2 recruitment and activation, whereas Pdgfrβ activation reduced IL-33 levels and suppressed ILC2 activity. Notably, diet-induced obesity markedly increased Pdgfrβ expression and Stat1 signaling, which inhibited IL-33 induction and ILC2 activation. Genetic deletion of Pdgfrβ restored beige fat formation in obese mice, improving whole-body metabolism. This study reveals that cold temperature exposure alone can trigger metabolic activation in aged mammals. However, reversing Pdgfrβ signaling in aged and obese mice not only restores beige fat formation but also renews metabolic function and enhances the immunological environment of white adipose tissue (WAT). These findings highlight Pdgfrβ as a crucial target for therapeutic strategies aimed at combating age- and obesity-related metabolic decline.

Detailed role of SR-A1 and SR-E3 in tumor biology, progression, and therapy.

The first host defense systems are the innate immune response and the inflammatory response. Among innate immune cells, macrophages, are crucial because they preserve tissue homeostasis and eradicate infections by phagocytosis, or the ingestion of particles. Macrophages exhibit phenotypic variability contingent on their stimulation state and tissue environment and may be detected in several tissues. Meanwhile, critical inflammatory functions are played by macrophage scavenger receptors, in particular, SR-A1 (CD204) and SR-E3 (CD206), in a variety of pathophysiologic events. Such receptors, which are mainly found on the surface of multiple types of macrophages, have different effects on processes, including atherosclerosis, innate and adaptive immunity, liver and lung diseases, and, more recently, cancer. Although macrophage scavenger receptors have been demonstrated to be active across the disease spectrum, conflicting experimental findings and insufficient signaling pathways have hindered our comprehension of the molecular processes underlying its array of roles. Herein, as SR-A1 and SR-E3 functions are often binary, either protecting the host or impairing the pathophysiology of cancers has been reviewed. We will look into their function in malignancies, with an emphasis on their recently discovered function in macrophages and the possible therapeutic benefits of SR-A1 and SR-E3 targeting.

HDI-STARR-seq: Condition-specific enhancer discovery in mouse liver in vivo.

STARR-seq and other massively-parallel reporter assays are widely used to discover functional enhancers in transfected cell models, which can be confounded by plasmid vector-induced type-I interferon immune responses and lack the multicellular environment and endogenous chromatin state of complex mammalian tissues. Here, we describe HDI-STARR-seq, which combines STARR-seq plasmid library delivery to the liver, by hydrodynamic tail vein injection (HDI), with reporter RNA transcriptional initiation driven by a minimal Albumin promoter, which we show is essential for mouse liver STARR-seq enhancer activity assayed 7 days after HDI. Importantly, little or no vector-induced innate type-I interferon responses were observed. Comparisons of HDI-STARR-seq activity between male and female mouse livers and in livers from males treated with an activating ligand of the transcription factor CAR (Nr1i3) identified many condition-dependent enhancers linked to condition-specific gene expression. Further, thousands of active liver enhancers were identified using a high complexity STARR-seq library comprised of ~50,000 genomic regions released by DNase-I digestion of mouse liver nuclei. When compared to stringently inactive library sequences, the active enhancer sequences identified were highly enriched for liver open chromatin regions with activating histone marks (H3K27ac, H3K4me1, H3K4me3), were significantly closer to gene transcriptional start sites, and were significantly depleted of repressive (H3K27me3, H3K9me3) and transcribed region histone marks (H3K36me3). HDI-STARR-seq offers substantial improvements over current methodologies for large scale, functional profiling of enhancers, including condition-dependent enhancers, in liver tissue in vivo, and can be adapted to characterize enhancer activities in a variety of species and tissues by selecting suitable tissue- and species-specific promoter sequences.

Chlorination of epithelial tight junction proteins by neutrophil myeloperoxidase promotes barrier dysfunction and mucosal inflammation.

Neutrophils (polymorphonuclear leukocytes, PMNs) comprise a major component of the immune cell infiltrate during acute mucosal inflammation and have an important role in molding the inflammatory tissue environment. While PMNs are essential to clearance of invading microbes, the major PMN antimicrobial enzyme myeloperoxidase (MPO) can also promote bystander tissue damage. We hypothesized that blocking MPO would attenuate acute colitis and prevent the development of chronic colitis by limiting bystander tissue damage. Using the acute and chronic dextran sodium sulfate model of murine colitis, we demonstrated that MPO-deficient mice experienced less inflammation and more rapidly resolved colitis relative to wild-type controls. Mechanistic studies demonstrated that activated MPO disrupted intestinal epithelial barrier function through the dysregulation of the epithelial tight junction proteins. Our findings revealed that activated MPO chlorinates tyrosine within several tight junction proteins, thereby promoting tight junction mislocalization and dysfunction. These observations in cell models and in murine colitis were validated in human intestinal biopsies from individuals with ulcerative colitis and revealed a strong correlation between disease severity (Mayo score) and tissue chlorinated tyrosine levels. In summary, these findings implicate MPO as a viable therapeutic target to limit bystander tissue damage and preserve mucosal barrier function during inflammation.

Epigenetic targets of Janus kinase inhibitors are linked to genetic risks of rheumatoid arthritis

BackgroundCurrent strategies that target cytokines (e.g., tumor necrosis factor (TNF)-α), or signaling molecules (e.g., Janus kinase (JAK)) have advanced the management for allergies and autoimmune diseases. Nevertheless, the molecular mechanism that underpins its clinical efficacy have largely remained elusive, especially in the local tissue environment. Here, we aimed to identify the genetic, epigenetic, and immunological targets of JAK inhibitors (JAKis), focusing on their effects on synovial fibroblasts (SFs), the major local effectors associated with destructive joint inflammation in rheumatoid arthritis (RA).MethodsSFs were activated by cytokines related to inflammation in RA, and were treated with three types of JAKis or a TNF-α inhibitor (TNFi). Dynamic changes in transcriptome and chromatin accessibility were profiled across samples to identify drug targets. Furthermore, the putative targets were validated using luciferase assays and clustered regularly interspaced short palindromic repeat (CRISPR)-based genome editing. ResultsWe found that both JAKis and the TNFi targeted the inflammatory module including IL6. Conversely, specific gene signatures that were preferentially inhibited by either of the drug classes were identified. Strikingly, RA risk enhancers for CD40 and TRAF1 were distinctively regulated by JAKis and the TNFi. We performed luciferase assays and CRISPR-based genome editing, and successfully fine-mapped the single causal variants in these loci, rs6074022-CD40 and rs7021049-TRAF1.ConclusionsJAKis and the TNFi had a direct impact on different RA risk enhancers, and we identified nucleotide-resolution targets for both drugs. Distinctive targets of clinically effective drugs could be useful for tailoring the application of these drugs and future design of more efficient treatment strategies.

Spatially and Single‐Cell Resolved Profiling of RNA Life Cycle and Epitranscriptomics

AbstractThe intricate network of cell functions relies on gene expression programs, where the whole RNA life cycle from DNA to protein is subjected to extensive transcriptional and post‐transcriptional gene regulation events. Established bulk RNA sequencing methods provide an averaged, transcriptome‐wide quantification of the RNA life cycle, including transcription, processing, translation, transport, and degradation through RNA‐protein interactions. Furthermore, numerous studies using bulk epitranscriptomic profiling unveiled that dynamic RNA modifications (e. g., N6‐Methyladenosine), add another layer of gene regulations. However, many regulatory events are cell‐type specific, subcellularly localized, and subjected to cell‐cell communications within the native tissue environment. Thanks to the advances in single‐cell sequencing, spatial sequencing, and highly multiplexed imaging methods, we can routinely measure single‐cell and spatial transcriptomics. Yet more comprehensive methods to profile every step of the RNA life cycle with single‐cell and spatial information are still lacking. In this review, we will summarize and compare early explorations in developing state‐of‐the‐art methods for spatially and single‐cell resolved mapping of RNA kinetics, translation, RNA‐protein interactions, and epitranscriptomics. It is promising that these new techniques will greatly facilitate our understanding of the RNA‐centered regulation landscapes in different cell types and how the post‐transcriptional regulations are interconnected within cellular and tissue architecture.

Differences in the characteristics and functions of brain and spinal cord regulatory T cells

T cells play an important role in the acquired immune response, with regulatory T cells (Tregs) serving as key players in immune tolerance. Tregs are found in nonlymphoid and damaged tissues and are referred to as “tissue Tregs”. They have tissue-specific characteristics and contribute to immunomodulation, homeostasis, and tissue repair through interactions with tissue cells. However, important determinants of Treg tissue specificity, such as antigen specificity, tissue environment, and pathology, remain unclear. In this study, we analyzed Tregs in the central nervous system of mice with ischemic stroke and experimental autoimmune encephalomyelitis (EAE), a mouse model of multiple sclerosis. The gene expression pattern of brain Tregs in the EAE model was more similar to that of ischemic stroke Tregs in the brain than to that of spinal cord Tregs. In addition, most T-cell receptors (TCRs) with high clonality were present in both the brain and spinal cord. Furthermore, Gata3+ and Rorc+ Tregs expressed TCRs recognizing MOG in the spinal cord, suggesting a tissue environment conducive to Rorc expression. Tissue-specific chemokine/chemokine receptor interactions in the spinal cord and brain influenced Treg localization. Finally, spinal cord- or brain-derived Tregs had greater anti-inflammatory capacities in EAE mice, respectively. Taken together, these findings suggest that the tissue environment, rather than pathogenesis or antigen specificity, is the primary determinant of the tissue-specific properties of Tregs. These findings may contribute to the development of novel therapies to suppress inflammation through tissue-specific Treg regulation.

Supersulfide metabolome of exhaled breath condensate for diagnostic biomarkers of esophageal cancer.

e15027 Background: The early estimate and detection of esophageal cancer (EC) is essentially required for continuous esophagogastroduodenoscopy and histopathological diagnosis. However, endoscopic examination is sometimes invasive, which may cause somehow limited clinical application and compliance. Also, the traditional blood tumor marker is unsuitable for a cancer screening. In recent years, the energy production by sulfur respiration in hypoxic environments in cancer tissues is getting spotlighted in tumor biology. The current study is aimed to evaluate usefulness of sulfur containing compounds as new biomarkers for EC by using blood samples and exhaled breath condensate (EBC) that can be readily obtained in a non-invasive fashion. Methods: Fifty EC patients were included in the study between June 2021 and September 2021. EBC and plasma samples were collected before starting any medicinal remedy including medication, chemotherapy, radiation, surgery, and endoscopic and dentistry maneuvers. Thirty healthy controls were recruited if they did not have any cancer history, surgery and aged over 50s preferred age for esophageal cancer. All samples were stored at -80℃ immediately after appropriate preparation until the following inspection. Then, sulfur metabolome analysis using LC-MS/MS was performed to see the difference of metabolic profile between the two groups. We used Student t tests for comparing two groups, and one -way ANOVA test for more than two groups, with significance set at P<0.05. To evaluate the diagnostic value of some metabolites, ROC curves and the AUC were calculated. Results: The supersulfide metabolic profiles were remarkably different between EC patients and controls. Especially, cysteine persulfide (CysSSH) was significantly increased in both EBC and plasma of the EC patients. The sensitivity and specificity of CysSSH in EBC were 60% and 96%, respectively, with an AUC of 0.71. The sensitivity and specificity of CysSSH in plasma were 49% and 96%, respectively, with an AUC of 0.73. In addition, homocysteine persulfide (HomoCysSSH) in plasma showed more significant difference than CysSSH and was able to distinguish EC patients from healthy subjects with AUC of 0.93 (sensitivity, 89%; specificity, 96%). The level of HomoCysSSH was correlated with that of CysSSH in EBC. The subgroup analysis for histological subtypes and tumor progression showed that both two metabolites were increased in EC patients regardless of histological type and disease’ progression. In particular, the amount of homoCysSSH in plasma was statistically higher in early-stage EC than that of controls (p<0.0001). Conclusions: Supersulfides like CysSSH and HomoCysSSH could be potential biomarkers for detecting EC. Cysteine persulfide from EBC may serve as a valuable non-invasive biomarker with similar detectable ability compared with several biomarkers of blood samples that are currently reported.

Comparative evaluation of six commercial adult toothpaste formulations reveals cytotoxicity and altered functions in a human oral melanocyte model: an in vitro study.

This study aims to compare six commercial adult toothpaste (labeled as A, B, C, D, E, and F) for cytotoxicity and melanocyte function alterations in vitro using primary human epidermal melanocytes from a Caucasian donor (HEMn-LP cells) as a model of oral melanocytes. Cells were incubated with toothpaste extracts (50% w/v) in culture media at dilutions (1:25, 1:50, 1:100, 1:200, 1:500, 1:800, and 1:1000) for 24h. MTS and LDH assays were used to assess cytotoxicity. The effects of noncytotoxic toothpaste concentrations on melanocyte functional endpoints were then examined using spectrophotometric methods. All toothpaste showed concentration-dependent cytotoxicity that was heterogeneous across toothpaste containing SLS detergent. IC50 values of cytotoxicity followed the order: A = E > C > B > D > F. To compare toothpaste, they were tested at 1:800 and 1:1000 dilutions that were noncytotoxic after 24h. None of the toothpaste affected cellular melanin production. However, toothpaste A, C, and D suppressed tyrosinase activity at both dilutions, while toothpaste B suppressed tyrosinase activity only at 1:800 dilution. Toothpaste A, C, E, and F elevated ROS production at 1:800 dilution, with no change at 1:1000 dilution. Toothpaste has a heterogeneous effect on melanocytes. Toothpaste B, E, and F at 1:1000 dilution were the safest as they did not alter melanocyte functions at this dilution, although toothpaste F is the least cytotoxic of these. Future studies are necessary to expand these results in a physiological environment of oral tissue. The findings of this study provide novel insight into the biocompatibility studies of toothpaste on oral melanocytes. They can aid dental practitioners and consumers in selecting noncytotoxic toothpaste that do not contribute to ROS generation by melanocytes in the oral cavity or lead to cytotoxicity and impaired cellular function.

Single-cell RNA sequencing reveals the evolution of the immune landscape during perihematomal edema progression after intracerebral hemorrhage

BackgroundPerihematomal edema (PHE) after post-intracerebral hemorrhage (ICH) has complex pathophysiological mechanisms that are poorly understood. The complicated immune response in the post-ICH brain constitutes a crucial component of PHE pathophysiology. In this study, we aimed to characterize the transcriptional profiles of immune cell populations in human PHE tissue and explore the microscopic differences between different types of immune cells.Methods9 patients with basal ganglia intracerebral hemorrhage (hematoma volume 50-100 ml) were enrolled in this study. A multi-stage profile was developed, comprising Group1 (n = 3, 0–6 h post-ICH, G1), Group2 (n = 3, 6–24 h post-ICH, G2), and Group3 (n = 3, 24–48 h post-ICH, G3). A minimal quantity of edematous tissue surrounding the hematoma was preserved during hematoma evacuation. Single cell RNA sequencing (scRNA-seq) was used to map immune cell populations within comprehensively resected PHE samples collected from patients at different stages after ICH.ResultsWe established, for the first time, a comprehensive landscape of diverse immune cell populations in human PHE tissue at a single-cell level. Our study identified 12 microglia subsets and 5 neutrophil subsets in human PHE tissue. What’s more, we discovered that the secreted phosphoprotein-1 (SPP1) pathway served as the basis for self-communication between microglia subclusters during the progression of PHE. Additionally, we traced the trajectory branches of different neutrophil subtypes. Finally, we also demonstrated that microglia-produced osteopontin (OPN) could regulate the immune environment in PHE tissue by interacting with CD44-positive cells.ConclusionsAs a result of our research, we have gained valuable insight into the immune-microenvironment within PHE tissue, which could potentially be used to develop novel treatment modalities for ICH.

The serum tenascin C level is a marker of metabolic disorder-related inflammation affecting pancreatic cancer prognosis

Obesity is a risk factor for pancreatic cancer development, partly due to the tissue environment of metabolic disorder-related inflammation. We aimed to detect a tissue environment marker triggered by obesity-related metabolic disorders related to pancreatic cancer progression. In murine experiments, Bl6/j mice fed a normal diet (ND) or a high-fat diet (HFD) were orthotopically injected with mPKC1, a murine-derived pancreatic cancer cell line. We used stocked sera from 140 pancreatic cancer patients for analysis and 14 colon polyp patients as a disease control. Compared with ND-fed mice, HFD-fed mice exhibited obesity, larger tumors, and worse prognoses. RNA sequencing of tumors identified tenascin C (TNC) as a candidate obesity-related serum tissue environment marker with elevated expression in tumors of HFD-fed mice. Serum TNC levels were greater in HFD-fed mice than in ND-fed mice. In pancreatic cancer patients, serum TNC levels were greater than those in controls. The TNC-high group had more metabolic disorders and greater CA19-9 levels than did the TNC-low group. There was no relationship between serum TNC levels and disease stage. Among 77 metastatic patients treated with chemotherapy, a high serum TNC concentration was an independent poor prognostic factor. Pancreatic cancer patients with high serum TNC levels experienced progression more rapidly.

Inflammation‐Activated Endogenous Macrophage‐Mediated Prodrug Delivery System Overcoming Biological Barriers for Enhanced Oral Meningitis Therapy

AbstractSignificant health risks are posed by meningitis due to its rapid progression, and challenges are encountered in intravenous antibiotic administration, especially in crossing the blood‐brain barrier. To address this, an inflammation‐activated, endogenous macrophage (MΦ)‐mediated oral prodrug delivery system is developed for targeted therapeutic interventions in bacterial meningitis treatment. This system is guided by inflammation‐derived chemoattractants and triggers drug release through inflammation‐induced reactive oxygen species (ROS). Comprised of naturally derived β‐glucans conjugated with the antibiotic cefotaxime (CTX) using a ROS‐responsive linker, nanoparticles (βGlus–CTX NPs) are formed in aqueous solutions. In a mouse model of Klebsiella pneumoniae‐induced meningitis, orally administered βGlus–CTX NPs are traversed by intestinal microfold cells, surpassing the intestine‐epithelial barrier, and are absorbed by resident endogenous MΦ. These MΦ‐mediated drug delivery vehicles are then traveled through the lymphatic and circulatory systems, crossing the compromised blood‐brain barrier, ultimately reaching inflamed brain tissues, guided by their derived chemoattractants. In ROS‐rich inflamed tissue environments, the linkers in the βGlus–CTX NPs are cleaved, releasing therapeutic CTX for localized treatment. Targeted antibiotic treatment for bacterial meningitis is offered by this oral, endogenous MΦ‐mediated prodrug delivery system, overcoming the robust gut‐to‐brain biological barriers and potentially enhancing effectiveness for comfortable home‐based treatment.

A Novel Ex Vivo Tumor Spheroid-Tissue Model for Investigating Microvascular Remodeling and Lymphatic Blood Vessel Plasticity.

Biomimetic tumor microenvironment models bridge the gap between in vitro and in vivo systems and serve as a useful way to address the modeling challenge of how to recreate the cell and system complexity associated with real tissues. Our laboratory has developed an ex vivo rat mesentery culturemodel, which allows for simultaneous investigation of blood and lymphatic microvascular network remodeling in an intact tissue environment. Given that angiogenesis and lymphangiogenesis are key contributors to the progression of cancer, the objective of this study was to combine tissue and tumor spheroid culture methods to establish a novel ex vivo tumor spheroid-tissue model by verifying its use for evaluating the effects of cancer cell behavior on the local microvascular environment. H1299 or A549 tumor spheroids were formed via hanging drop culture and seeded onto rat mesenteric tissues harvested from adult male Wistar rats. Tissues with transplanted spheroids were cultured in serum-free media for 3 to 5days. PECAM, NG2, CD11b, and αSMA labeling identified endothelial cells, pericytes, immune cells, and smooth muscle cells, respectively. Time-lapse imaging confirmed cancer cell type specific migration. In addition to increasing PECAM positive capillary sprouting and LYVE-1 positive endothelial cell extensions indicative of lymphangiogenesis, tumor spheroid presence induced the formation of lymphatic/blood vessel connections and the formation of hybrid, mosaic vessels that were characterized by discontinuous LYVE-1 labeling. The results support the application of a novel tumor spheroid microenvironment model for investigating cancer cell-microvascular interactions.

Continuous protein-density gradients: A new approach to correlate physical cues with cell response.

To assess cellular behavior within heterogeneous tissues, such as bone, skin, and nerves, scaffolds with biophysical gradients are required to adequately replicate the in vivo interaction between cells and their native microenvironment. In this study, we introduce a strategy for depositing ultrathin films comprised of laminin-111 with precisely controlled biophysical gradients onto planar substrates using the Langmuir-Blodgett (LB) technique. The gradient is created by controlled desynchronization of the barrier compression and substrate withdrawal speed during the LB deposition process. Characterization of the films was performed using techniques such as atomic force microscopy and confocal fluorescence microscopy, enabling the comprehensive analysis of biophysical parameters along the gradient direction. Furthermore, human adipose-derived stem cells were seeded onto the gradient films to investigate the influence of protein density on cell attachment, showing that the distribution of the cells can be modulated by the arrangement of the laminin at the air-water interface. The presented approach not only allowed us to gain insights into the intricate interplay between biophysical cues and cell behavior within complex tissue environments, but it is also suited as a screening approach to determine optimal protein concentrations to achieve a target cellular output.

Urolithin A's Role in Alleviating Severe Acute Pancreatitis via Endoplasmic Reticulum-Mitochondrial Calcium Channel Modulation.

Severe acute pancreatitis (SAP), characterized by pancreatic acinar cell death, currently lacks effective targeted therapies. Ellagic acid (EA), rich in pomegranate, shows promising anti-inflammatory and antioxidant effects in SAP treatment. However, the roles of other forms of EA, such as plant extracellular vesicles (EVs) extracted from pomegranate, and Urolithin A (UA), converted from EA through gut microbiota metabolism in vivo, have not been definitively elucidated. Our research aimed to compare the effects of pomegranate-derived EVs (P-EVs) and UA in the treatment of SAP to screen an effective formulation and to explore its mechanisms in protecting acinar cells in SAP. By comparing the protective effects of P-EVs and UA on injured acinar cells, UA showed superior therapeutic effects than P-EVs. Subsequently, we further discussed the mechanism of UA in alleviating SAP inflammation. In vivo animal experiments found that UA could not only improve the inflammatory environment of pancreatic tissue and peripheral blood circulation in SAP mice but also revealed that the mechanism of UA in improving SAP might be related to mitochondria and endoplasmic reticulum (ER) through the results including pancreatic tissue transcriptomics and transmission electron microscopy. Further research found that UA could regulate ER-mitochondrial calcium channels and reduce pancreatic tissue necroptosis. In vitro experiments of mouse pancreatic organoids and acinar cells also confirmed that UA could improve pancreatic inflammation by regulating the ER-mitochondrial calcium channel and necroptosis pathway proteins. This study not only explored the therapeutic effect of plant EVs on SAP but also revealed that UA could alleviate SAP by regulating ER-mitochondrial calcium channel and reducing acinar cell necroptosis, providing insights into the pathogenesis and potential treatment of SAP.

Dynamic Imaging of Lipid Droplets in Cells and Tissues by Using Dioxaborine Barbiturate-Based Fluorogenic Probes.

Lipids are essential for various cellular functions, including energy storage, membrane flexibility, and signaling molecule production. Maintaining proper lipid levels is important to prevent health problems such as cancer, neurodegenerative disorders, cardiovascular diseases, obesity, and diabetes. Monitoring cellular lipid droplets (LDs) in real-time with high resolution can provide insights into LD-related pathways and diseases owing to the dynamic nature of LDs. Fluorescence-based imaging is widely used for tracking LDs in live cells and animal models. However, the current fluorophores have limitations such as poor photostability and high background staining. Herein, we developed a novel fluorogenic probe based on a push-pull interaction combined with aggregation-induced emission enhancement (AIEE) for dynamic imaging of LDs. Probe 1 exhibits favorable membrane permeability and spectroscopic characteristics, allowing specific imaging of cellular LDs and time-lapse imaging of LD accumulation. This probe can also be used to examine LDs in fruit fly tissues in various metabolic states, serving as a highly versatile and specific tool for dynamic LD imaging in cellular and tissue environments.

MAPP unravels frequent co-regulation of splicing and polyadenylation by RNA-binding proteins and their dysregulation in cancer

Maturation of eukaryotic pre-mRNAs via splicing and polyadenylation is modulated across cell types and conditions by a variety of RNA-binding proteins (RBPs). Although there exist over 1,500 RBPs in human cells, their binding motifs and functions still remain to be elucidated, especially in the complex environment of tissues and in the context of diseases. To overcome the lack of methods for the systematic and automated detection of sequence motif-guided pre-mRNA processing regulation from RNA sequencing (RNA-Seq) data we have developed MAPP (Motif Activity on Pre-mRNA Processing). Applying MAPP to RBP knock-down experiments reveals that many RBPs regulate both splicing and polyadenylation of nascent transcripts by acting on similar sequence motifs. MAPP not only infers these sequence motifs, but also unravels the position-dependent impact of the RBPs on pre-mRNA processing. Interestingly, all investigated RBPs that act on both splicing and 3’ end processing exhibit a consistently repressive or activating effect on both processes, providing a first glimpse on the underlying mechanism. Applying MAPP to normal and malignant brain tissue samples unveils that the motifs bound by the PTBP1 and RBFOX RBPs coordinately drive the oncogenic splicing program active in glioblastomas demonstrating that MAPP paves the way for characterizing pre-mRNA processing regulators under physiological and pathological conditions.

Customized Proteinaceous Nanoformulation for In Vivo Chemical Reprogramming.

Sweat gland (SwG) regeneration is crucial for the functional rehabilitation of burn patients. In vivo chemical reprogramming that harnessing the patient's own cells in damaged tissue is of substantial interest to regenerate organs endogenously by pharmacological manipulation, which could compensate for tissue loss in devastating diseases and injuries, for example, burns. However, achieving in vivo chemical reprogramming is challenging due to the low reprogramming efficiency and an unfavorable tissue environment. Herein, this work has developed a functionalized proteinaceous nanoformulation delivery system containing prefabricated epidermal growth factor structure for on-demand delivery of a cocktail of seven SwG reprogramming components to the dermal site. Such a chemical reprogramming system can efficiently induce the conversion of epidermal keratinocytesinto SwG myoepithelial cells, resulting in successful in situ regeneration of functional SwGs. Notably, in vivo chemical reprogramming of SwGs is achieved for the first time with an impressive efficiency of 30.6%, surpassing previously reported efficiencies. Overall, this proteinaceous nanoformulation provides a platform for coordinating the target delivery of multiple pharmacological agents and facilitating in vivo SwG reprogramming by chemicals. This advancement greatly improves the clinical accessibility of in vivo reprogramming and offers a non-surgical, non-viral, and cell-free strategy for in situ SwG regeneration.

Chitosan-PLGA mucoadhesive nanoparticles for gemcitabine repurposing for glioblastoma therapy

Glioblastoma (GBM) is a highly deadly brain tumor that does not respond satisfactorily to conventional treatment. The non-alkylating agent gemcitabine (GEM) has been proposed for treating GBM. It can overcome MGMT protein-mediated resistance, a major limitation of conventional therapy with the alkylating agent temozolomide (TMZ). However, GEM's high systemic toxicity and poor permeability across the blood–brain barrier (BBB) pose significant challenges for its delivery to the brain. Thus, mucoadhesive poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) coated with chitosan (CH), suitable for intranasal GEM delivery, were proposed in this work. A central composite design (CCD) was implemented for NPs optimization, and NPs with appropriate characteristics for intranasal administration were obtained. in vitro studies revealed that the NPs possess excellent mucoadhesive properties and the ability to selectively release GEM in the simulated tumor tissue environment. in vitro studies using two human GBM cell lines (U215 and T98G) revealed the NPs' ability to promote GEM's antiproliferative activity to sensitize cells to the effect of TMZ. The findings of this work demonstrate that the developed CH-GEM-NPs are suitable delivery systems for GEM, both as a single therapy and as a chemosensitizer to the GBM gold standard therapy.