Endogenous Function Research Articles

Generation of p27icreER transgenic mice: A tool for inducible gene expression in supporting cells in the cochlea

The loss of cochlear hair cells (HCs) is an important cause of sensorineural hearing loss, and finding ways to regenerate HCs would be the ideal way forward for restoring hearing. In this research field, tamoxifen-inducible Cre recombinase (iCreER) transgenic mice and the Cre-loxp system are widely used to manipulate gene expression in supporting cells (SCs), which lie beneath the sensory HCs and are a natural source for HC regeneration. However, many iCreER transgenic lines are of limited utility because they cannot target all subtypes of SCs or they cannot be used in the adult stage. In this study, a new line of iCreER transgenic mice, the p27-P2A-iCreERT2 knock-in mouse strain, was generated by inserting the P2A-iCreERT2 cassette immediately in front of the stop codon of p27, which kept the endogenous expression and function of p27 intact. Using a reporter mouse line with tdTomato fluorescence, we showed that the p27iCreER transgenic line can target all subtypes of cochlear SCs, including Claudius cells. p27-CreER activity in SCs was observed in both the postnatal and the adult stage, suggesting that this mouse strain can be useful for research work in adult cochlear HC regeneration. We then overexpressed Gfi1, Pou4f3, and Atoh1 in p27+ SCs of P6/7 mice using this strain and successfully induced many new Myo7a/tdTomato double-positive cells, further confirming that the p27-P2A-iCreERT2 mouse strain is a new and reliable tool for cochlear HC regeneration and hearing restoration.

Modelling pandemic risks for policy analysis and forecasting.

What were the economic effects of vaccination campaign, agents' adaptation to containment measures, and fiscal and monetary measures during the COVID-19 pandemic? To quantify these effects, we augment the ECB's macro-econometric model with an endogenous epidemiological block, providing one of the first institutional policy models with epidemiological elements. The model tracks closely actual pandemic developments by relying on detailed epidemiological data and by nesting a wide range of features, including vaccination campaigns, emergence of new variants and learning effects. Importantly, it includes an endogenous policy reaction function for containment measures, allowing counterfactual simulations. Our simulation results show that: (i) agents' adaptation to containment measures over time was key in reducing negative macroeconomic consequences of lockdowns, (ii) the vaccination campaign slowed down infection rates and hospitalizations, enabling a relaxation of containment measures and avoiding a sharp double dip in economic activity and (iii) complementary fiscal and monetary policy interventions provided support to the economy.

Racial Differences in Head Pain and Other Pain-Related Outcomes After Mild Traumatic Brain Injury.

Recent research suggests that mild traumatic brain injury (TBI) may exert deleterious effects on endogenous pain modulatory function, potentially underlying the elevated risk for persistent headaches following injury. Accumulating research also shows race differences in clinical and experimental pain, with African Americans (AA) generally reporting more severe pain, worse pain modulation, and greater pain sensitivity compared with Caucasians. However, race differences in pain-related outcomes following mild TBI have rarely been studied. The purpose of this study was to explore race differences in endogenous pain modulation, pain sensitivity, headache pain, and psychological factors among AA and Caucasian individuals with mild TBI in the first month following injury compared with healthy controls and across time. Patients with mild TBI were recruited from local emergency department trauma centers. Sixty-three participants with mild TBI (AAs: n = 23, Caucasians: n = 40) enrolled in this study and completed study sessions at 1-2 weeks and 1-month post-injury. Forty-one mild-TBI-free control participants (AAs: n = 11, Caucasians: n = 30), matched on age and sex, completed one study session. Assessments included a Headache Survey, Pain Catastrophizing Scale, Center for Epidemiological Studies-Depression Scale (CES-D), and quantitative sensory testing (QST) to measure endogenous pain modulatory function. QST included conditioned pain modulation (CPM) to measure endogenous pain inhibitory function and temporal summation (TS) of pain and pressure pain thresholds (PPTs) of the head to measure pain sensitization and sensitivity. Two-way analysis of variance (ANOVA) was used to determine whether the outcome measures differed as a function of race, mild TBI, and time. Mediation analysis was used to explore potential mediators for the race differences in headache pain intensity. The results showed that AA participants with mild TBI reported significantly greater headache pain and pain catastrophizing and exhibited higher pain sensitivity and worse pain modulation on QST compared with Caucasian participants with mild TBI. These same race differences were not observed among the healthy TBI-free control sample. The mediation analyses showed complete mediation for the relation between race and headache pain intensity by pain catastrophizing at 1-2 weeks and 1-month post-injury. Overall, the results of this study suggest that AAs compared with Caucasians are characterized by psychological and pain modulatory profiles following mild TBI that could increase the risk for the development of intense and persistent headaches following injury.

Bacteriophages inhibit and evade cGAS-like immune function in bacteria

A fundamental strategy of eukaryotic antiviral immunity involves the cGAS enzyme, which synthesizes 2',3'-cGAMP and activates the effector STING. Diverse bacteria contain cGAS-like enzymes that produce cyclic oligonucleotides and induce anti-phage activity, known as CBASS. However, this activity has only been demonstrated through heterologous expression. Whether bacteria harboring CBASS antagonize and co-evolve with phages is unknown. Here, we identified an endogenous cGAS-like enzyme in Pseudomonas aeruginosa that generates 3',3'-cGAMP during phage infection, signals to a phospholipase effector, and limits phage replication. In response, phages express an anti-CBASS protein ("Acb2") that forms a hexamer with three 3',3'-cGAMP molecules and reduces phospholipase activity. Acb2 also binds to molecules produced by other bacterial cGAS-like enzymes (3',3'-cUU/UA/UG/AA) and mammalian cGAS (2',3'-cGAMP), suggesting broad inhibition of cGAS-based immunity. Upon Acb2 deletion, CBASS blocks lytic phage replication and lysogenic induction, but rare phages evade CBASS through major capsid gene mutations. Altogether, we demonstrate endogenous CBASS anti-phage function and strategies of CBASS inhibition and evasion.

Heterogeneity in hormone-dependent breast cancer and therapy: Steroid hormones, HER2, melanoma antigens, and cannabinoid receptors

Breast cancer is the most frequently diagnosed cancer and the leading cause of death by cancer among women worldwide. The prognosis of the disease and patients’ response to different types of therapies varies in different subgroups of this heterogeneous disease. The subgroups are based on histological and molecular characteristics of the tumor, especially the expression of estrogen (ER) and progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2). Hormone-dependent breast cancer, determined predominantly by the presence of ER, is the most common type of breast cancer. Patients with hormone-dependent breast cancer have an available targeted therapy, however, tumor cells can develop resistance to the therapy, which is a major obstacle limiting the success of treatment and enabling relapse to metastatic disease. The complicated crosstalk of both tumor-intrinsic and exogenous factors may contribute to endocrine resistance, although the underlying molecular details are still enigmatic. For example, the expression of the melanoma antigen genes (MAGE) correlates with a worse clinical prognosis and therapy resistance in many types of cancers, including breast cancer. Recent studies suggested that cancers co-opt MAGEs’ physiological functions to promote therapy resistance and potentially metastasis development. The response to the therapy can be also affected by the concurrent use of alternative therapy, e.g., cannabinoid use is popular among breast cancer patients. Cannabinoids interact with endogenous estrogen function, however, how they interfere with breast cancer therapy is still poorly understood. In this review, we summarize the role of ER, PR, and HER2 in hormone-dependent breast cancer; provide current knowledge of MAGEs and cannabinoid receptors in breast cancer; ultimately discuss the potential interlacement of their signaling paths which may underlay diverse responses to therapies in breast cancer patients simultaneously using cannabinoids. These interactions are poorly understood but critical for the advancement of conventional and complementary treatment options for patients, particularly the ones with metastatic disease.

Laforin targets malin to glycogen in Lafora progressive myoclonus epilepsy.

Glycogen is the largest cytosolic macromolecule and is kept in solution through a regular system of short branches allowing hydration. This structure was thought to solely require balanced glycogen synthase and branching enzyme activities. Deposition of overlong branched glycogen in the fatal epilepsy Lafora disease (LD) indicated involvement of the LD gene products laforin and the E3 ubiquitin ligase malin in regulating glycogen structure. Laforin binds glycogen, and LD-causing mutations disrupt this binding, laforin-malin interactions and malin's ligase activity, all indicating a critical role for malin. Neither malin's endogenous function nor location had previously been studied due to lack of suitable antibodies. Here, we generated a mouse in which the native malin gene is tagged with the FLAG sequence. We show that the tagged gene expresses physiologically, malin localizes to glycogen, laforin and malin indeed interact, at glycogen, and malin's presence at glycogen depends on laforin. These results, and mice, open the way to understanding unknown mechanisms of glycogen synthesis critical to LD and potentially other much more common diseases due to incompletely understood defects in glycogen metabolism.

Autoregressive distributed lag estimation of bank financing and Nigerian manufacturing sector capacity utilization

<abstract> <p>This study examined the short-term and long-term relationship between credit financing by commercial banks and capacity utilization of the manufacturing sector in Nigeria. The study employed both classical Multiple Linear Regression (OLS-MLR) and the autoregressive distributed lag model (ARDL) to analyze data representing the period 1981–2020 relating to sectoral credit finance,labor employment,and capacity utilization from the <xref ref-type="bibr" rid="b6">Central Bank of Nigeria Statistical Bulletin (2020)</xref> and <xref ref-type="bibr" rid="b38">World Bank Development Indicators (2021)</xref>. Further,the two estimation procedures were performed within a classical endogenous Cobb-Douglas production function framework that takes technical change into consideration. The bounds test indicated no long-term relationship between bank financing and average capacity utilization of the manufacturing sector in Nigeria. However,the ARDL results revealed that bank financing exerts a positive but insignificant short-term impact on the average capacity utilization of the manufacturing sector in Nigeria. Consequently,the researchers affirm that credit financing by commercial banks in Nigeria has no significant impact on the capacity utilization of the country's manufacturing sector,in neither the short run nor the long run.</p> </abstract>

C-peptide as an investigatory tool for endogenous insulin secretion in Type 2 diabetes mellitus patients of Mahakaushal region

Background: Type 2 diabetes mellitus (T2DM) is a disease state of chronic hyperglycemia that occurs due to decrease insulin secretion or attenuated insulin response or both. Insulin resistance with relative insulin deficiency is a peculiar feature of T2DM. Proinsulin is synthesized by the beta cell of the pancreas. Before secretion into the portal vein, proinsulin cleaves into equal quantities of insulin and C-peptide. The secreted insulin gets extensively metabolized by the liver and has a shorter half-life than C-peptide. Thus, C-peptide levels more accurately perceive the endogenous insulin secretion of the pancreas. Hence, C-peptide can be used to interpret the significant pathophysiology behind T2DM. Aims and Objectives: The aim of the study was to perceive endogenous insulin secretion or beta cell functioning of the pancreas by measuring C-peptide levels in T2DM patients. Materials and Methods: The cross-sectional study were conducted on 120 random T2DM patients attending the outpatient clinic of tertiary care hospital (Netaji Subash Chandra Bose Medical College, Jabalpur) from January 2021 to August 2022. All T2DM patients were evaluated with fasting C-peptide levels. Results: Among 120 cases,25 (20.8%) have low C-peptide levels of <1.1 ng/dL, indicating poor insulin reserve.33 (27.5%) have normal C-peptide levels, and approximately half −62 (51.6%) have high C-peptide levels of more than 3.3 ng/dL, indicating adequate endogenous insulin secretion and insulin resistance is the significant pathophysiology behind T2DM. Conclusion: C-peptide level is a useful investigation to perceive endogenous insulin secretion and beta cell function of the pancreas. Insulin resistance rather than insulin deficiency is the significant pathophysiology behind T2DM.

High-efficiency knock-in of degradable tags (dTAG) at endogenous loci in cell lines.

The dTAG system is a versatile strategy for tunable control of protein abundance and facilitates the time-resolved assessment of disease-associated protein function. A "co-opted" fusion-based degron peptide, the "dTAG" facilitates the study of endogenous protein function when knocked-in at the endogenous genetic loci of proteins of interest. We combine CRISPR/Cas9 mediated induction of double-strand breaks (DSB) with the delivery of a single-stranded DNA HDR-donor-template via crude preparations of recombinant adeno-associated virus (rAAV). Our approach to knock-in of large (1-2kb) DNA fragments via crude-rAAV mediated HDR donor delivery is rapid and inexpensive. It facilitates genetic modification of a variety of human as well as mouse cell lines at high efficiency and precision.

Disease-associated oligodendrocyte signatures in neurodegenerative disease: the known and unknown.

Disease-associated oligodendrocyte signatures in neurodegenerative disease: the known and unknown.

Revisiting institutional credibility of informal rental housing in Shenzhen: For dwelling function or exclusion function?

The credibility thesis premises that an institution's endogenous credibility and function, rather than its form, ensures its persistence. Informal rental housing (IRH), an informal housing institution in China, was suggested to serve as a dwelling for low-income residents in previous research on institutional credibility. Combining the institutional functionalism in credibility thesis and the relational and constructivist perspective in the strategic-relational approach (SRA), this research on two distinct SPRH cases in Shenzhen aims to re-examine the credibility thesis, moving the emphasis away from institutional functions toward the interaction between function and dysfunction, and their substitutability in the relation reconstruction dynamics. It reveals that the informal housing institution's credibility rationale has shifted in Shenzhen. Instead of serving a dwelling function, IRH is becoming an investment tool for profit-making and a part of public service for government targets, contributing to the credibility of informal housing and exacerbating the exclusion of the disadvantaged groups from urban areas. IRH's institutional credibility is contingent upon not just the endogenous institutional function, but also on the interplay of the function and dysfunction embedded in its institutional environment.

Circadian age, chronological age, and Alzheimer’s dementia

AbstractBackgroundIn older adults, circadian rhythms show alterations in multiple dimensions with aging and during Alzheimer’s dementia progression. We propose that circadian function may serve as a unique gauge of biological age (i.e., circadian age), and that individuals with greater circadian age than chronological age have increased risk of Alzheimer’s dementia.MethodWe constructed a regression model with chronological age as the predicting target. The model prediction was termed circadian age. A softplus activation function was used to ensure positivity. The model was optimized to minimize the mean‐squared prediction error while penalizing the covariance between chronological age and prediction error. Cosinor analysis, nonparametric analysis, uniform phase empirical mode decomposition, and detrended fluctuation analysis were performed on baseline actigraphy data of 882 participants (age: 80.1±7.3; female/male: 692/190) from the Rush Memory and Aging Project who were cognitively intact and were not taking sleep medications. These analyses resulted in 23 features for circadian daily activity patterns as model inputs. The optimal model was trained through cross‐validation for the penalization parameter and applied to follow‐up actigraphy data. We compared circadian age among participants at different cognitive stages, evaluated the longitudinal change of circadian age, and examined the association of circadian age with incident Alzheimer’s dementia.ResultChronological age explained 24.8% of the variance in circadian age. At analytical baseline, participants with Alzheimer’s dementia had significantly greater circadian–chronological age deviation (CCD) than cognitively normal participants (2.98±1.43 vs. ‐0.13±0.42 years, p=0.04). For each 1‐year increase in chronological age, circadian age increased by 1.05±0.06 years (p<0.001), suggesting accelerated circadian aging. Among baseline cognitively normal participants, greater CCD was associated with an increased risk of Alzheimer’s dementia independent from chronological age, sex, total daily activity, sleep fragmentation, vascular disease and risk factors, and depressive symptoms. For a 10‐year increase in CCD, the hazard ratio was 1.23 (95% CI: 1.06‐1.42).ConclusionCircadian daily patterns can be integrated to predict chronological age. Older circadian age than chronological age is an independent risk factor for Alzheimer’s dementia. Future work should refine the determination of health status for training dataset and examine whether circadian age links with endogenous circadian function.

Characterization of the Doublesex/MAB-3 transcription factor DMD-9 in Caenorhabditis elegans.

DMD-9 is a Caenorhabditis elegans Doublesex/MAB-3 Domain transcription factor (TF) of unknown function. Single-cell transcriptomics has revealed that dmd-9 is highly expressed in specific head sensory neurons, with lower levels detected in non-neuronal tissues (uterine cells and sperm). Here, we characterized endogenous dmd-9 expression and function in hermaphrodites and males to identify potential sexually dimorphic roles. In addition, we dissected the trans- and cis-regulatory mechanisms that control DMD-9 expression in neurons. Our results show that of the 22 neuronal cell fate reporters we assessed in DMD-9-expressing neurons, only the neuropeptide-encoding flp-19 gene is cell-autonomously regulated by DMD-9. Further, we did not identify defects in behaviors mediated by DMD-9 expressing neurons in dmd-9 mutants. We found that dmd-9 expression in neurons is regulated by 4 neuronal fate regulatory TFs: ETS-5, EGL-13, CHE-1, and TTX-1. In conclusion, our study characterized the DMD-9 expression pattern and regulatory logic for its control. The lack of detectable phenotypes in dmd-9 mutant animals suggests that other proteins compensate for its loss.

Determination of potential toxicodynamic differences of pyrethroid insecticides on native voltage-sensitive sodium channels in juvenile versus adult rat brain

Microtransplantation of neurolemma tissue fragments from mammalian brain into the plasma membrane of Xenopus laevis oocytes is a tool to examine the endogenous structure and function of various ion channels and receptors associated with the central nervous system. Microtransplanted neurolemma can originate from a variety of sources, contain ion channels and receptors in their native configuration, and are applicable to examine diseases associated with different channelopathies. Here, we examined potential age-related differences in voltage-sensitive sodium channel (VSSC) expression and concentration-dependent responses to pyrethroids following the microtransplantation of juvenile or adult rat brain tissue (neurolemma) into X. laevis oocytes. Using automated western blotting, adult neurolemma exhibited a 2.5-fold higher level of expression of VSSCs compared with juvenile neurolemma. The predominant isoform expressed in both tissues was Nav1.2. However, adult neurolemma expressed 2.8-fold more Nav1.2 than juvenile and expressed Nav1.6 at a significantly higher level (2.2-fold). Microtransplanted neurolemma elicited ion currents across the plasma membrane of oocytes following membrane depolarization using two electrode voltage clamp electrophysiology. A portion of this current was sensitive to tetrodotoxin (TTX) and this TTX-sensitive current was abolished when external sodium ion was replaced by choline ion, functionally demonstrating the presence of native VSSC. Increasing concentrations of permethrin or deltamethrin exhibited concentration-dependent increases in inward TTX-sensitive current in the presence of niflumic acid from both adult and juvenile tissues following a pulsed depolarization of the oocyte plasma membrane. Concentration-dependent response curves illustrate that VSSCs associated with juvenile neurolemma were up to 2.5-fold more sensitive to deltamethrin than VSSCs in adult neurolemma. In contrast, VSSCs from juvenile neurolemma were less sensitive to permethrin than adult VSSCs at lower concentrations (0.6–0.8-fold) but were more sensitive at higher concentrations (up to 2.4-fold). Nonetheless, because the expected concentrations in human brains following realistic exposure levels are approximately 21- (deltamethrin) to 333- (permethrin) times below the threshold concentration for response in rat neurolemma-injected oocytes, age-related differences, if any, are not likely to be toxicologically relevant.

LBMON185 Isthmin-1 As A Modulator Of Metabolic Health

Abstract Insulin resistance involves impaired glucose clearance capacity by the skeletal muscle and adipose tissue and is also associated with muscle loss. However, the underlying mechanistic link between diabetes and muscle loss is not well understood. Here, we identify Isthmin-1 (Ism1) as a secreted signaling protein with multi-organ actions. By performing untargeted phosphoproteomics revealing the global signaling actions of Ism1, we identify that Ism1 stimulates adipose and skeletal muscle glucose uptake and an increase in skeletal muscle protein synthesis. Mechanistically, Ism1 activates pAKT-mTOR-S6 signaling independently of insulin or the insulin receptor. In mice, Ism1 ablation results in impaired glucose clearance capacity and reduced insulin sensitivity, demonstrating an endogenous function for Ism1 in systemic glucose regulation. Notably, the administration of recombinant Ism1 is sufficient to ameliorate diabetes in a diet-induced obese mouse model. Ism1 ablation also results in smaller skeletal muscle fiber size and lower muscle protein content, demonstrating that Ism1 is required for muscle proteostasis. These findings reveal a new secreted protein hormone that activates anabolic pathways in muscle and adipose tissue. Presentation: Monday, June 13, 2022 12:30 p.m. - 2:30 p.m.

Endogenous opioid systems alterations in pain and opioid use disorder.

Decades of research advances have established a central role for endogenous opioid systems in regulating reward processing, mood, motivation, learning and memory, gastrointestinal function, and pain relief. Endogenous opioid systems are present ubiquitously throughout the central and peripheral nervous system. They are composed of four families, namely the μ (MOPR), κ (KOPR), δ (DOPR), and nociceptin/orphanin FQ (NOPR) opioid receptors systems. These receptors signal through the action of their endogenous opioid peptides β-endorphins, dynorphins, enkephalins, and nociceptins, respectfully, to maintain homeostasis under normal physiological states. Due to their prominent role in pain regulation, exogenous opioids-primarily targeting the MOPR, have been historically used in medicine as analgesics, but their ability to produce euphoric effects also present high risks for abuse. The ability of pain and opioid use to perturb endogenous opioid system function, particularly within the central nervous system, may increase the likelihood of developing opioid use disorder (OUD). Today, the opioid crisis represents a major social, economic, and public health concern. In this review, we summarize the current state of the literature on the function, expression, pharmacology, and regulation of endogenous opioid systems in pain. Additionally, we discuss the adaptations in the endogenous opioid systems upon use of exogenous opioids which contribute to the development of OUD. Finally, we describe the intricate relationship between pain, endogenous opioid systems, and the proclivity for opioid misuse, as well as potential advances in generating safer and more efficient pain therapies.

Therapeutic modulation of gene expression in the disease state: Treatment strategies and approaches for the development of next-generation of the epigenetic drugs.

Epigenetic dysregulation is an important determinant of many pathological conditions and diseases. Designer molecules that can specifically target endogenous DNA sequences provide a means to therapeutically modulate gene function. The prokaryote-derived CRISPR/Cas editing systems have transformed our ability to manipulate the expression program of genes through specific DNA and RNA targeting in living cells and tissues. The simplicity, utility, and robustness of this technology have revolutionized epigenome editing for research and translational medicine. Initial success has inspired efforts to discover new systems for targeting and manipulating nucleic acids on the epigenetic level. The evolution of nuclease-inactive and RNA-targeting Cas proteins fused to a plethora of effector proteins to regulate gene expression, epigenetic modifications and chromatin interactions opened up an unprecedented level of possibilities for the development of "next-generation" gene therapy therapeutics. The rational design and construction of different types of designer molecules paired with viral-mediated gene-to-cell transfers, specifically using lentiviral vectors (LVs) and adeno-associated vectors (AAVs) are reviewed in this paper. Furthermore, we explore and discuss the potential of these molecules as therapeutic modulators of endogenous gene function, focusing on modulation by stable gene modification and by regulation of gene transcription. Notwithstanding the speedy progress of CRISPR/Cas-based gene therapy products, multiple challenges outlined by undesirable off-target effects, oncogenicity and other virus-induced toxicities could derail the successful translation of these new modalities. Here, we review how CRISPR/Cas-based gene therapy is translated from research-grade technological system to therapeutic modality, paying particular attention to the therapeutic flow from engineering sophisticated genome and epigenome-editing transgenes to delivery vehicles throughout efficient and safe manufacturing and administration of the gene therapy regimens. In addition, the potential solutions to some of the obstacles facing successful CRISPR/Cas utility in the clinical research are discussed in this review. We believe, that circumventing these challenges will be essential for advancing CRISPR/Cas-based tools towards clinical use in gene and cell therapies.

Phase III, randomised, double-blind, placebo-controlled, multicentre trial to evaluate the efficacy and safety of rhGAD65 to preserve endogenous beta cell function in adolescents and adults with recently diagnosed type 1 diabetes, carrying the genetic HLA DR3-DQ2 haplotype: the DIAGNODE-3 study protocol

IntroductionType 1 diabetes (T1D) is an autoimmune disease leading to the destruction of the insulin-producing beta cells resulting in insulin deficiency and hyperglycaemic. Today, no approved therapy exists to halt...

Hydrogen Sulfide Regulates Macrophage Function in Cardiovascular Diseases.

Significance: Hydrogen sulfide (H2S) is an endogenous gasotransmitter that plays a vital role in immune system regulation. Recently, the regulation of macrophage function by H2S has been extensively and actively recognized. Recent Advances: The mechanisms by which endogenous H2S controls macrophage function have attracted increasing attention. The generation of endogenous H2S from macrophages is mainly catalyzed by cystathionine-γ-lyase. H2S is involved in the macrophage activation and inflammasome formation, which contributes to macrophage apoptosis, adhesion, chemotaxis, and polarization. In addition, H2S has redox ability and interacts with reactive oxygen species to prevent oxidative stress. Moreover, H2S epigenetically regulates gene expression. Critical Issues: In this article, the generation of endogenous H2S in macrophages and its regulatory effect on macrophage function are reviewed. In addition, the signal transduction targeting macrophages by H2S is also addressed. Finally, the potential therapeutic effect of H2S on macrophages is discussed. Future Directions: Further experiments are required to explore the involvement of endogenous H2S in the regulation of macrophage function in various physiological and pathophysiological processes and elucidate the mechanisms involved. Regarding the clinical translation of H2S, further exploration of the application of H2S in inflammation-related diseases is needed. Antioxid. Redox Signal. 38, 45-56.

Biomaterials-based nanoparticles conjugated to regulatory T cells provide a modular system for localized delivery of pharmacotherapeutic agents.

Type 1 diabetes (T1D) presents with two therapeutic challenges: the need to correct underlying autoimmunity and restore β-cell mass. We harnessed the unique capacity of regulatory T cells (Tregs) and the T cell receptor (TCR) to direct tolerance induction along with tissue-localized delivery of therapeutic agents to restore endogenous β-cell function. Specifically, we designed a combinatorial therapy involving biomaterials-based poly(lactic-co-glycolic acid) nanoparticles co-loaded with the Treg growth factor, IL-2, and the β-cell regenerative agent, harmine (a tyrosine-regulated kinase 1A [DYRK1A] inhibitor), conjugated to the surface of Tregs. We observed continuous elution of IL-2 and harmine from nanoparticles for at least 7 days in vitro. When conjugated to primary human Tregs, IL-2 nanoparticles provided sufficient IL-2 receptor signaling to support STAT5 phosphorylation for sustained phenotypic stability and viability in culture. Inclusion of poly-L-lysine (PLL) during nanoparticle-cell coupling dramatically increased conjugation efficiency, providing sufficient IL-2 to support in vitro proliferation of IL-2-dependent CTLL-2 cells and primary murine Tregs. In 12-week-old female non-obese diabetic mice, adoptive transfer of IL-2/harmine nanoparticle-conjugated NOD.BDC2.5 Tregs, which express an islet antigen-specific TCR, significantly prevented diabetes demonstrating preserved in vivo viability. These data provide the preclinical basis to develop a biomaterials-optimized cellular therapy to restore immune tolerance and promote β-cell proliferation in T1D through receptor-targeted drug delivery within pancreatic islets.