α Cell dysfunction in islets from nondiabetic, glutamic acid decarboxylase autoantibody-positive individuals

BACKGROUNDMultiple islet autoantibodies (AAbs) predict the development of type 1 diabetes (T1D) and hyperglycemia within 10 years. By contrast, T1D develops in only approximately 15% of individuals who are positive for single AAbs (generally against glutamic acid decarboxylase [GADA]); hence, the single GADA+ state may represent an early stage of T1D.METHODSHere, we functionally, histologically, and molecularly phenotyped human islets from nondiabetic GADA+ and T1D donors.RESULTSSimilar to the few remaining β cells in the T1D islets, GADA+ donor islets demonstrated a preserved insulin secretory response. By contrast, α cell glucagon secretion was dysregulated in both GADA+ and T1D islets, with impaired glucose suppression of glucagon secretion. Single-cell RNA-Seq of GADA+ α cells revealed distinct abnormalities in glycolysis and oxidative phosphorylation pathways and a marked downregulation of cAMP-dependent protein kinase inhibitor β (PKIB), providing a molecular basis for the loss of glucose suppression and the increased effect of 3-isobutyl-1-methylxanthine (IBMX) observed in GADA+ donor islets.CONCLUSIONWe found that α cell dysfunction was present during the early stages of islet autoimmunity at a time when β cell mass was still normal, raising important questions about the role of early α cell dysfunction in the progression of T1D.FUNDINGThis work was supported by grants from the NIH (3UC4DK112217-01S1, U01DK123594-02, UC4DK112217, UC4DK112232, U01DK123716, and P30 DK019525) and the Vanderbilt Diabetes Research and Training Center (DK20593).

Single-cell multi-omics analysis of human pancreatic islets reveals novel cellular states in type 1 diabetes

Type 1 diabetes (T1D) is an autoimmune disease in which immune cells destroy insulin-producing beta cells. The aetiology of this complex disease is dependent on the interplay of multiple heterogeneous cell types in the pancreatic environment. Here, we provide a single-cell atlas of pancreatic islets of 24 T1D, autoantibody-positive and nondiabetic organ donors across multiple quantitative modalities including ~80,000 cells using single-cell transcriptomics, ~7,000,000 cells using cytometry by time of flight and ~1,000,000 cells using in situ imaging mass cytometry. We develop an advanced integrative analytical strategy to assess pancreatic islets and identify canonical cell types. We show that a subset of exocrine ductal cells acquires a signature of tolerogenic dendritic cells in an apparent attempt at immune suppression in T1D donors. Our multimodal analyses delineate cell types and processes that may contribute to T1D immunopathogenesis and provide an integrative procedure for exploration and discovery of human pancreatic function.

Highly Multiplexed Image Analysis of Intestinal Tissue Sections in Patients With Inflammatory Bowel Disease

BACKGROUND & AIMS

Significant progress has been made since the first report of inflammatory bowel disease (IBD) in 1859, after decades of research that have contributed to the understanding of the genetic and environmental factors involved in IBD pathogenesis. Today, a range of treatments is available for directed therapy, mostly targeting the overactive immune response. However, the mechanisms by which the immune system contributes to disease pathogenesis and progression are not fully understood. One challenge hindering IBD research is the heterogeneous nature of the disease and the lack of understanding of how immune cells interact with one another in the gut mucosa. Introduction of a technology that enables expansive characterization of the inflammatory environment of human IBD tissues may address this gap in knowledge.

METHODS

We used the imaging mass cytometry platform to perform highly multiplex image analysis of IBD and healthy deidentified intestine sections (6 Crohn's disease compared to 6 control ileum; 6 ulcerative colitis compared to 6 control colon). The acquired images were graded for inflammation severity by analysis of adjacent H&E tissue sections. We assigned more than 300,000 cells to unique cell types and performed analyses of tissue integrity, epithelial activity, and immune cell composition.

RESULTS

The intestinal epithelia of patients with IBD exhibited increased proliferation rates and expression of HLA-DR compared to control tissues, and both features were positively correlated with the severity of inflammation. The neighborhood analysis determined enrichment of regulatory T cell interactions with CD68⁺ macrophages, CD4⁺ T cells, and plasma cells in both forms of IBD, whereas activated lysozyme C⁺ macrophages were preferred regulatory T cell neighbors in Crohn's disease but not ulcerative colitis.

CONCLUSIONS

Altogether, our study shows the power of imaging mass cytometry and its ability to both quantify immune cell types and characterize their spatial interactions within the inflammatory environment by a single analysis platform.

Single-cell analysis of the human pancreas in type 2 diabetes using multi-spectral imaging mass cytometry

Type 2 diabetes mellitus (T2D) is a chronic age-related disorder characterized by hyperglycemia due to the failure of pancreatic beta cells to compensate for increased insulin demand. Despite decades of research, the pathogenic mechanisms underlying T2D remain poorly defined. Here, we use imaging mass cytometry (IMC) with a panel of 34 antibodies to simultaneously quantify markers of pancreatic exocrine, islet, and immune cells and stromal components. We analyze over 2 million cells from 16 pancreata obtained from donors with T2D and 13 pancreata from age-similar non-diabetic controls. In the T2D pancreata, we observe significant alterations in islet architecture, endocrine cell composition, and immune cell constituents. Thus, both HLA-DR-positive CD8 T cells and macrophages are enriched intra-islet in the T2D pancreas. These efforts demonstrate the utility of IMC for investigating complex events at the cellular level in order to provide insights into the pathophysiology of T2D.

Highly multiplexed 2-dimensional imaging mass cytometry analysis of HBV-infected liver

Studies of human hepatitis B virus (HBV) immune pathogenesis are hampered by limited access to liver tissues and technologies for detailed analyses. Here, utilizing imaging mass cytometry (IMC) to simultaneously detect 30 immune, viral, and structural markers in liver biopsies from patients with hepatitis B e antigen⁺ (HBeAg⁺) chronic hepatitis B, we provide potentially novel comprehensive visualization, quantitation, and phenotypic characterizations of hepatic adaptive and innate immune subsets that correlated with hepatocellular injury, histological fibrosis, and age. We further show marked correlations between adaptive and innate immune cell frequencies and phenotype, highlighting complex immune interactions within the hepatic microenvironment with relevance to HBV pathogenesis.

Tumor-infiltrating mast cells are associated with resistance to anti-PD-1 therapy

Anti-PD-1 therapy is used as a front-line treatment for many cancers, but mechanistic insight into this therapy resistance is still lacking. Here we generate a humanized (Hu)-mouse melanoma model by injecting fetal liver-derived CD34⁺ cells and implanting autologous thymus in immune-deficient NOD-scid IL2Rγ^null (NSG) mice. Reconstituted Hu-mice are challenged with HLA-matched melanomas and treated with anti-PD-1, which results in restricted tumor growth but not complete regression. Tumor RNA-seq, multiplexed imaging and immunohistology staining show high expression of chemokines, as well as recruitment of FOXP3⁺ Treg and mast cells, in selective tumor regions. Reduced HLA-class I expression and CD8⁺/Granz B⁺ T cells homeostasis are observed in tumor regions where FOXP3⁺ Treg and mast cells co-localize, with such features associated with resistance to anti-PD-1 treatment. Combining anti-PD-1 with sunitinib or imatinib results in the depletion of mast cells and complete regression of tumors. Our results thus implicate mast cell depletion for improving the efficacy of anti-PD-1 therapy.

Immune checkpoint therapies (ICT) are promising for treating various cancers, but response rates vary. Here the authors show, in mouse models, that tumor-infiltrating mast cells colocalize with regulatory T cells, coincide with local reduction of MHC-I and CD8 T cells, and is associated with resistance to ICT, which can be reversed by c-kit inhibitor treatment.

Multiplexed In Situ Imaging Mass Cytometry Analysis of the Human Endocrine Pancreas and Immune System in Type 1 Diabetes

The interaction between the immune system and endocrine cells in the pancreas is crucial for the initiation and progression of type 1 diabetes (T1D). Imaging mass cytometry (IMC) enables multiplexed assessment of the abundance and localization of more than 30 proteins on the same tissue section at 1-μm resolution. Herein, we have developed a panel of 33 antibodies that allows for the quantification of key cell types including pancreatic exocrine cells, islet cells, immune cells, and stromal components. We employed this panel to analyze 12 pancreata obtained from donors with clinically diagnosed T1D and 6 pancreata from non-diabetic controls. In the pancreata from donors with T1D, we simultaneously visualized significant alterations in islet architecture, endocrine cell composition, and immune cell presentation. Indeed, we demonstrate the utility of IMC to investigate complex events on the cellular level that will provide new insights on the pathophysiology of T1D.

Single-Cell Mass Cytometry Analysis of the Human Endocrine Pancreas

The human endocrine pancreas consists of multiple cell types and plays a critical role in glucose homeostasis. Here, we apply mass cytometry technology to measure all major islet hormones, proliferative markers, and readouts of signaling pathways involved in proliferation at single-cell resolution. Using this innovative technology, we simultaneously examined baseline proliferation levels of all endocrine cell types from birth through adulthood, as well as in response to the mitogen harmine. High-dimensional analysis of our marker protein expression revealed three major clusters of beta cells within individuals. Proliferating beta cells are confined to two of the clusters.

Hepatitis B Virus--Specific and Global T-Cell Dysfunction in Chronic Hepatitis B

BACKGROUND & AIMS

T cells play a critical role in viral infection. We examined whether T-cell effector and regulatory responses can define clinical stages of chronic hepatitis B (CHB).

METHODS

We enrolled 200 adults with CHB who participated in the National Institutes of Health-supported Hepatitis B Research Network from 2011 through 2013 and 20 uninfected individuals (controls). Peripheral blood lymphocytes from these subjects were analyzed for T-cell responses (proliferation and production of interferon gamma and interleukin 10) to overlapping hepatitis B virus (HBV) peptides (preS, S, preC, core, and reverse transcriptase), influenza matrix peptides, and lipopolysaccharide. T-cell expression of regulatory markers FOXP3, programmed death-1, and cytotoxic T lymphocyte-associated antigen-4 was examined by flow cytometry. Immune measures were compared with clinical parameters, including physician-defined immune-active, immune-tolerant, or inactive CHB phenotypes, in a blinded fashion.

RESULTS

Compared with controls, patients with CHB had weak T-cell proliferative, interferon gamma, and interleukin 10 responses to HBV, with increased frequency of circulating FOXP3(+)CD127(-) regulatory T cells and CD4(+) T-cell expression of programmed death-1 and cytotoxic T lymphocyte-associated antigen-4. T-cell measures did not clearly distinguish between clinical CHB phenotypes, although the HBV core-specific T-cell response was weaker in hepatitis B e antigen (HBeAg)(+) than HBeAg(-) patients (percent responders: 3% vs 23%; P = .00008). Although in vitro blockade of programmed death-1 or cytotoxic T lymphocyte-associated antigen-4 increased T-cell responses to HBV, the effect was weaker in HBeAg(+) than HBeAg(-) patients. Furthermore, T-cell responses to influenza and lipopolysaccharide were weaker in CHB patients than controls.

CONCLUSIONS

HBV persists with virus-specific and global T-cell dysfunction mediated by multiple regulatory mechanisms, including circulating HBeAg, but without distinct T-cell-based immune signatures for clinical phenotypes. These findings suggest additional T-cell-independent or regulatory mechanisms of CHB pathogenesis that warrant further investigation.

Effect of black tea extract on herpes simplex virus-1 infection of cultured cells

Background

The purpose of this investigation was to determine if black tea extract (BTE), consisting primarily of flavanol compounds called theaflavins, could inhibit herpes simplex virus type-1 (HSV-1) infection in cultured A549 (human epithelial) and Vero cells.

Methods

The effect of BTE both on A549 and Vero cultured cells and on HSV-1 was assessed by using phase contrast and fluorescent microscopy, and cell viability and proliferation assays. After establishing the maximum non-cytotoxic concentration of BTE, A549 and Vero cells and HSV-1 virions were treated with varying concentrations of BTE, respectively. A549 and Vero cells were infected with HSV-1 with green fluorescent protein (GFP) insert at the UL46 gene. The effect of infectivity was determined by viral DNA extraction followed by PCR, plaque assays, adsorption assays, and electrophoresis of PCR products.

Results

BTE was not cytotoxic to A549 and Vero cells, as confirmed by cell viability and proliferation assays, in which BTE treated groups paralleled the positive control group. For both cell lines, plaque assays and fluorescent microscopy indicated an inverse relationship between BTE concentration (from 0.14 μM – 1.4 mM) and HSV-1 infectivity. Specifically, PCR and electrophoresis showed a reduction in the viral genome following treatment with BTE. In addition, there was a noticeable decrease in the amount of viral plaques for BTE treated samples in the adsorption assays.

Conclusions

BTE consisting primarily of theaflavins is not cytotoxic and can reduce or block the production of infectious HSV-1 virions in cultured A549 and Vero cells, thus inhibiting the infectivity of the virus by interfering in the attachment, penetration and viral DNA replication of HSV-1 particles. These findings indicate that BTE enriched with theaflavins has the potential to be developed as a safe, therapeutic antiviral agent to prevent the spread of HSV-1.

IL-10-induced gp130 expression in mouse mast cells permits IL-6 trans-signaling

It is reported that human and mouse mast cells express the IL-27R, which consists of WSX-1 (the IL-27Rα subunit) and the signal-transducing subunit gp130. Although it has been proposed that IL-27 may negatively regulate mast cell-dependent, immediate hypersensitivity responses directly, this has yet to be examined specifically. We found that mouse BMMC and primary peritoneal mast cells are unresponsive to IL-27. Consistent with this, gp130 protein in resting BMMC was not on the cell surface to a measurable degree but was found intracellularly, and data are consistent with incompletely processed N-linked glycosylation. Furthermore, BMMC constitutively expressed SOCS3, a major negative regulator of gp130 signaling. However, BMMC stimulation with IL-10 and consequential STAT3 activation increased gp130 expression, which resulted in a functional gp130 receptor on the BMMC cell surface. IL-10 has not been previously shown to regulate gp130 expression, which on the BMMC surface, permitted IL-6 trans-signaling, found to increase survival under limiting conditions and enhance IL-13 and TNF-α secretion. This study identifies factors that regulate mouse mast cell gp130 expression and signaling and makes conspicuous the limitations of using cultured mouse mast cells to study the effects of the IL-6/IL-12 cytokine family on mast cell biology.

A requirement for the p85 PI3K adapter protein BCAP in the protection of macrophages from apoptosis induced by endoplasmic reticulum stress

Macrophages are innate immune cells that play key roles in regulation of the immune response and in tissue injury and repair. In response to specific innate immune stimuli, macrophages may exhibit signs of endoplasmic reticulum (ER) stress and progress to apoptosis. Factors that regulate macrophage survival under these conditions are poorly understood. In this study, we identified B cell adapter protein (BCAP), a p85 PI3K-binding adapter protein, in promoting survival in response to the combined challenge of LPS and ER stress. BCAP was unique among nine PI3K adapter proteins in being induced >10-fold in response to LPS. LPS-stimulated macrophages incubated with thapsigargin, a sarcoplasmic/endoplasmic reticulum calcium ATPase inhibitor that induces ER stress, underwent caspase-3 activation and apoptosis. Macrophages from BCAP(-/-) mice exhibited increased apoptosis in response to these stimuli. BCAP-deficient macrophages demonstrated decreased activation of Akt, but not ERK, and, unlike BCAP-deficient B cells, expressed normal amounts of the NF-κB subunits, c-Rel and RelA. Retroviral transduction of BCAP-deficient macrophages with wild-type BCAP, but not a Y4F BCAP mutant defective in binding the SH2 domain of p85 PI3K, reversed the proapoptotic phenotype observed in BCAP-deficient macrophages. We conclude that BCAP is a nonredundant PI3K adapter protein in macrophages that is required for maximal cell survival in response to ER stress. We suggest that as macrophages engage their pathogenic targets, innate immune receptors trigger increased expression of BCAP, which endows them with the capacity to withstand further challenges from ongoing cellular insults, such as ER stress.

Phagocytosis in macrophages lacking Cbl reveals an unsuspected role for Fc gamma receptor signaling and actin assembly in target binding

Fc gamma receptor (Fc gammaR)-mediated phagocytosis is known to require tyrosine kinases (TKs). We identified c-Cbl and Cbl-b as proteins that undergo tyrosine phosphorylation during phagocytosis. Cbl-deficient macrophages displayed enhanced Fc gammaR-mediated signaling and phagocytosis. Surprisingly, binding of IgG-coated targets (EIgG) was also enhanced. c-Cbl-deficient macrophages expressed less Fc gammaRIIb, the inhibitory Fc gamma receptor; however, this did not account for enhanced target binding. We isolated the function of one Fc receptor isoform, Fc gammaRI, using IgG2a-coated targets (EIgG2a). Cbl-deficient macrophages demonstrated a disproportionate increase in binding EIgG2a, suggesting that signal strength regulates binding efficiency toward opsonized targets. In resting cells, Fc gammaRI colocalized with the Src family TK Hck in F-actin-rich structures, which was enhanced in Cbl-deficient macrophages. Target binding was sensitive to TK inhibitors, profoundly inhibited following depletion of cholesterol, and ablated at 4 degrees C or in the presence of inhibitors of actin polymerization. Sensitivity of EIgG binding to cytoskeletal disruption was inversely proportional to opsonin density. These findings challenge the view that Fc gammaR-mediated binding is a passive event. They suggest that dynamic engagement of TKs and the cytoskeleton enables macrophages to serve as cellular "Venus fly traps", with the capacity to capture phagocytic targets under conditions of limiting opsonin density.

An LKB1 AT-AC intron mutation causes Peutz-Jeghers syndrome via splicing at noncanonical cryptic splice sites

Peutz-Jeghers syndrome (PJS) is an autosomal dominant disorder associated with gastrointestinal polyposis and an increased cancer risk. PJS is caused by germline mutations in the tumor suppressor gene LKB1. One such mutation, IVS2+1A>G, alters the second intron 5' splice site, which has sequence features of a U12-type AT-AC intron. We report that in patients, LKB1 RNA splicing occurs from the mutated 5' splice site to several cryptic, noncanonical 3' splice sites immediately adjacent to the normal 3' splice site. In vitro splicing analysis demonstrates that this aberrant splicing is mediated by the U12-dependent spliceosome. The results indicate that the minor spliceosome can use a variety of 3' splice site sequences to pair to a given 5' splice site, albeit with tight constraints for maintaining the 3' splice site position. The unusual splicing defect associated with this PJS-causing mutation uncovers differences in splice-site recognition between the major and minor pre-mRNA splicing pathways.

Acupuncture in general practice

BACKGROUND

Many Australian general practitioners have embraced acupuncture as a viable modality in the treatment of a wide range of conditions commonly seen in general practice, especially those which do not respond to conventional therapy. Many practitioners, such as myself, have become convinced of the efficacy through personal experience.

OBJECTIVE

This article reviews what acupuncture is and its place in the modern doctor's therapeutic armamentarium.

DISCUSSION

A clinically attractive element in medical acupuncture, is that positive responses can be obtained without the use of drugs, and in the more chronic conditions, by significantly reducing the need for drugs. This elimination or reduction in the need for medication is very important to every doctor and patient, for reasons of dependence and side effects.