Immunoglobulin G4 -related gastrointestinal disease associated with type 1 autoimmune pancreatitis: A case report.

Immunoglobulin G4 (IgG4)-related diseaseis a systemic inflammatory condition of unknown etiology characterized by increases in serum IgG4 and in the number of IgG4-positive cells in affected tissues. One of the commonly involved locations is the pancreas; this condition is known as type 1 autoimmune pancreatitis (AIP). Type 1 AIP, which shows a biliary stricture in the intrapancreatic bile duct, can be misdiagnosed as a malignancy due to similar cholangiography findings and clinical presentation. In rare cases complicated by post-bulbar duodenal ulcers, differentiating between type 1 AIP and malignancies is even more difficult. An 81-year-old male was referred to our hospital for the treatment of a pancreatic head mass and obstructive jaundice. Serological and radiological findings were consistent with both type 1 AIP and a malignancy. Gastroduodenoscopy revealed a post-bulbar duodenal ulcer with endoscopic features that evoked malignant duodenal invasion. Although biopsies were negative for malignant cells, subsequent bleeding from the lesion suggested the progression of malignancy, which led to surgical resection. Pancreatoduodenectomy and pathological examination indicated that type 1 AIP was present. Simultaneously, the involvement of IgG4-related disease in the ulcerative lesion was suggested. To our knowledge, this is the first reported case of type 1 AIP complicated by post-bulbar duodenal ulcers, which was misdiagnosed as malignancy and considered an IgG4-related gastrointestinal disease associated with type 1 AIP.

Genome-wide mapping of native co-localized G4s and R-loops in living cells.

The interplay between G4s and R-loops are emerging in regulating DNA repair, replication, and transcription. A comprehensive picture of native co-localized G4s and R-loops in living cells is currently lacking. Here, we describe the development of HepG4-seq and an optimized HBD-seq methods, which robustly capture native G4s and R-loops, respectively, in living cells. We successfully employed these methods to establish comprehensive maps of native co-localized G4s and R-loops in human HEK293 cells and mouse embryonic stem cells (mESCs). We discovered that co-localized G4s and R-loops are dynamically altered in a cell type-dependent manner and are largely localized at active promoters and enhancers of transcriptional active genes. We further demonstrated the helicase Dhx9 as a direct and major regulator that modulates the formation and resolution of co-localized G4s and R-loops. Depletion of Dhx9 impaired the self-renewal and differentiation capacities of mESCs by altering the transcription of co-localized G4s and R-loops -associated genes. Taken together, our work established that the endogenous co-localized G4s and R-loops are prevalently persisted in the regulatory regions of active genes and are involved in the transcriptional regulation of their linked genes, opening the door for exploring broader roles of co-localized G4s and R-loops in development and disease.

Clinical characteristics of chronic sclerosing sialadenitis as a distinctive entity from primary Sjögren's syndrome.

Objective: This study aimed to elucidate the clinical and laboratory differences between chronic sclerosing sialadenitis (CSS) and primary Sjögren's syndrome (pSS), highlighting CSS as a distinct pathological entity within the spectrum of salivary gland pathology. Methods: This retrospective, single-center study was conducted at Seoul St. Mary's Hospital between January 2000 and December 2022. Patients diagnosed with CSS via salivary gland biopsy were included, and those with IgG4-related disease (IgG4-RD) or other confounding factors were excluded. Clinical and laboratory CSS profiles were compared with those of a control group of patients with typical pSS from the Korean Initiative of Primary Sjögren's Syndrome (KISS) prospective cohort study. Twenty-one with CSS and 501 patients with pSS from Seoul St. Mary's Hospital were retrospectively analyzed. Results: Patients with CSS were older at diagnosis, had a lower prevalence of ocular symptoms, and exhibited distinct immunological markers compared to those with pSS. Logistic regression analysis revealed that anti-Ro antibody positivity, elevated erythrocyte sedimentation rate levels, low serum complement 3 levels, and accompanying dry eye symptoms were factors distinguishing pSS from CSS. Conclusion: Even after excluding IgG4-RD, CSS was significantly different from pSS in terms of clinical and laboratory findings. Recognition of these differences is crucial for the accurate diagnosis and management of CSS, underscoring its status as a distinct pathological entity among salivary gland pathologies.

Immunoglobulin G4 in primary Sjögren's syndrome and IgG4-related disease - connections and dissimilarities.

Primary Sjögren's syndrome (pSS) is an autoimmune disease, with B cell hyperactivation and autoantibody production as its immunological hallmarks. Although the distinction between immunoglobulin G4-related disease (IgG4-RD) and pSS, based on the presence or absence of certain autoantibodies, seems easy to make, possibility of elevated serum IgG4 concentration and often similar organ involvement may lead to a misdiagnosis. The increased serum concentration of IgG4 in IgG4-RD is not clearly linked to the pathogenesis of IgG-RD and it has been suggested that it may constitute just an epiphenomenon. The aim of this article is to discuss the presence of IgG4 in pSS and IgG4-RD and its potential significance for these two diseases.

Küttner's Tumor and Autoimmune Pancreatitis as Metachronous Manifestations of IgG4-Related Disease.

Immunoglobulin G4-related disease (IgG4-RD) is a multiorgan, fibro-inflammatory condition that presents with painless organ swelling, lymphoplasmacytic infiltration, and obliterative phlebitis, often showing a favorable response to corticosteroid therapy. The most affected organs include the pancreas, kidneys, retroperitoneum, lacrimal glands, and salivary glands. Diagnosis relies on serological, imaging, and histopathological findings, with glucocorticoids as the primary treatment. Despite its reversible nature and good prognosis in many cases, long-term complications such as organ dysfunction or malignancy can still occur. International collaborative efforts have enhanced the understanding, diagnosis, and management of IgG4-RD, emphasizing the importance of comprehensive diagnostic criteria and appropriate therapeutic strategies. Herein, we present an interesting case of a geriatric male who was referred to our clinic because of concern for pancreatic cancer. We diagnosed the patient with autoimmune pancreatitis, a manifestation of IgG4-RD. The patient experienced a dramatic response to steroid therapy and is currently on maintenance therapy.

Fulminant Myocarditis in Patients With Autoimmune Disease That Requires Extracorporeal Membrane Oxygenation Support.

Myocarditis is a potentially life-threatening inflammatory disease of the myocardium, often resulting from infectious and immune-mediated responses. Clinical presentation in severe cases often results in a devastating illness requiring extracorporeal membrane oxygenation support as a result of cardiogenic shock. Although endomyocardial biopsy is still considered the gold standard for diagnosis, it often reveals nonspecific lymphocytic infiltration. Because the precise cause is usually unknown, the initial treatment typically involves immunosuppression and frequent assessment of myocardial contractility. This report presents 3 rare cases of autoimmune diseases (polymyositis, immunoglobulin G4-related disease, and systemic lupus erythematosus) that require extracorporeal membrane oxygenation support as a result of fulminant myocarditis, including their follow-up periods.

Opportunities and challenges with G-quadruplexes as promising targets for drug design.

INTRODUCTION: G-quadruplexes (G4s) are secondary structures formed in guanine-rich regions of nucleic acids (both DNA and RNA). G4s are significantly enriched at regulatory genomic regions and are associated with important biological processes ranging from telomere homeostasis and genome instability to transcription and translation. Importantly, G4s are related to health and diseases such as cancer, neurological diseases, as well as infections with viruses and microbial pathogens. Increasing evidence suggests the potential of G4s for designing new diagnostic and therapeutic strategies although in vivo studies are still at early stages. AREAS COVERED: This review provides an updated summary of the literature describing the impact of G4s in human diseases and different approaches based on G4 targeting in therapy. EXPERT OPINION: Within the G4 field, most of the studies have been performed in vitro and in a descriptive manner. Therefore, detailed mechanistic understanding of G4s in the biological context remains to be deciphered. In clinics, the use of G4s as therapeutic targets has been hindered due to the low selectivity profile and poor drug-like properties of G4 ligands. Future research on G4s may overcome current methodological and interventional limitations and shed light on these unique structural elements in the pathogenesis and treatment of diseases.

Spinal cord compression by cystic IgG4-related spinal pachymeningitis mimicking neurocysticercosis: a case report.

BACKGROUND: To report a case of IgG4-related pachymeningitis presenting with cystic lesions mimicking neurocysticercosis. CASE PRESENTATION: A 40-year-old female patient with tetraparesis, dysphagia and dysphonia was evaluated with clinical examination, magnetic resonance imaging, and meningeal biopsy. Magnetic resonance imaging (MRI) revealed diffuse pachymeningeal enhancement involving the cranial, cervical, thoracic, and lumbar segments with spinal cord compression and cystic lesions. CSF immunology was initially positive for cysticercus cellulosae. After disease progression a meningeal biopsy was compatible with IgG4 related disease. The patient had partial response to rituximab and needed multiple surgical procedures for spinal cord decompression and CSF shunting. CONCLUSIONS: This case highlights the possibility of IgG4-related disease in patients with diffuse pachymeningitis causing spinal cord compression, even with cystic lesions on MRI. Diagnosis of IgG4-related pachymeningitis is paramount due to the possibility of treatment response to immunotherapy, particularly to anti-CD20 agents.

Label-Free and Universal CRISPR/Cas12a-Based Detection Platform for Nucleic Acid Biomarkers.

CRISPR/Cas12a has been widely used in molecular diagnostics due to its excellent trans-cleavage activity. However, conventional reporters, such as F/Q-labeled single-stranded DNA (ssDNA) reporters, enzyme-labeled reporters, and spherical nucleic acid reporters, require complex modification or labeling processes. In this study, we have developed a rapid, universal, and label-free CRISPR/Cas12a-based biomarker detection platform via designing a G-quadruplex (G4) containing a hairpin structure as the reporter. The hairpin loop design of hairpin G4 improves the cleavage efficiency of Cas12a and the signal strength of the G4 binding ligand. Meanwhile, the incorporation of a G4 binding dye (protoporphyrin IX) eliminates the need for complex modifications. The CRISPR-hairpin G4 detection platform is capable of detecting ssDNA, double-stranded DNA, genetic RNAs, and miRNAs. Moreover, this platform achieves label-free detection in clinical samples, demonstrating its practical applicability and efficiency.

A NRAS mRNA G-quadruplex structure-targeting small-molecule ligand reactivating DNA damage response in human cancer cells for combination therapy with clinical PI3K inhibitors.

The Neuroblastoma RAS (NRAS) oncogene homologue plays crucial roles in diverse cellular processes such as cell proliferation, survival, and differentiation. Several strategies have been developed to inhibit NRAS or its downstream effectors; however, there is no effective drug available to treat NRAS-driven cancers and thus new approaches are needed to be established. The mRNA sequence expressing NRAS containing several guanine(G)-rich regions may form quadruplex structures (G4s) and regulate NRAS translation. Therefore, targeting NRAS mRNA G4s to repress NRAS expression at translational level with ligands may be a feasible strategy against NRAS-driven cancers but it is underexplored. We reported herein a NRAS mRNA G4-targeting ligand, B3C, specifically localized in cytoplasm in HeLa cells. It effectively downregulates NRAS proteins, reactivates the DNA damage response (DDR), causes cell cycle arrest in G2/M phase, and induces apoptosis and senescence. Moreover, combination therapy with NARS mRNA G4-targeting ligands and clinical PI3K inhibitors for cancer cells inhibition treatment is unexplored, and we demonstrated that B3C combining with PI3Ki (pictilisib (GDC-0941)) showed potent antiproliferation activity against HeLa cells (IC50 = 1.03 µM (combined with 10 µM PI3Ki) and 0.42 µM (combined with 20 µM PI3Ki)) and exhibited strong synergistic effects in inhibiting cell proliferation. This study provides new insights into drug discovery against RAS-driven cancers using this conceptually new combination therapy strategy.

Characterization of 1,1- and 1,2-ethenedithiol, elusive compounds of potential astrochemical interest.

CONTEXT: 1,1- and 1,2-ethenedithiol are elusive systems that could potentially exist in interstellar space, similar to analogous diols. In this paper, we investigate the structure, stability, and bonding characteristics of these compounds as well as the ions produced by protonation, deprotonation, or simple ionization processes. 1,2-ethenedithiol has two isomers, Z and E, with the most stable conformer being syn-anti for the Z isomer and anti-anti for the E isomer. However, the energy gaps between the different conformers are never larger than 6 kJ·mol-1. For 1,1-ethenedithiol, the global minimum is the syn-anti conformer. The vertical and adiabatic ionization processes as well as the intrinsic basicities and acidities of these families of compounds were analyzed and compared with those of the corresponding diols previously reported in the literature. This comparison revealed not only the numerical differences in these thermodynamic properties but also distinct trends between the two families of compounds. METHODS: State-of-the-art G4 ab initio calculations were employed to calculate the structures and total energies of the systems under investigation. The QTAIM, ELF, and NBO approaches were used to analyze the electron density of all the neutral and charged systems included in our study. Van der Waals contributions, when relevant, were analyzed by locating regions of low reduced density gradient(s) using the NCIPLOT approach.

Cross-Effects in Folding and Phase Transitions of hnRNP A1 and C9Orf72 RNA G4 In Vitro.

Abnormal intracellular phase transitions in mutant hnRNP A1 may underlie the development of several neurodegenerative diseases. The risk of these diseases increases upon C9Orf72 repeat expansion and the accumulation of the corresponding G-quadruplex (G4)-forming RNA, but the link between this RNA and the disruption of hnRNP A1 homeostasis has not been fully explored so far. Our aim was to clarify the mutual effects of hnRNP A1 and C9Orf72 G4 in vitro. Using various optical methods and atomic force microscopy, we investigated the influence of the G4 on the formation of cross-beta fibrils by the mutant prion-like domain (PLD) of hnRNP A1 and on the co-separation of the non-mutant protein with a typical SR-rich fragment of a splicing factor (SRSF), which normally drives the assembly of nuclear speckles. The G4 was shown to act in a holdase-like manner, i.e., to restrict the fibrillation of the hnRNP A1 PLD, presumably through interactions with the PLD-flanking RGG motif. These interactions resulted in partial unwinding of the G4, suggesting a helicase-like activity of hnRNP A1 RGG. At the same time, the G4 was shown to disrupt hnRNP A1 co-separation with SRSF, suggesting its possible contribution to pathology through interference with splicing regulation.

The first embryonic landscape of G-quadruplexes related to myogenesis.

BACKGROUND: DNA G-quadruplexes (G4s) represent a distinctive class of non-canonical DNA secondary structures. Despite their recognition as potential therapeutic targets in some cancers, the developmental role of G4 structures remains enigmatic. Mammalian embryonic myogenesis studies are hindered by limitations, prompting the use of chicken embryo-derived myoblasts as a model to explore G4 dynamics. This study aims to reveal the embryonic G4s landscape and elucidate the underlying mechanisms for candidate G4s that influence embryonic myogenesis. RESULTS: This investigation unveils a significant reduction in G4s abundance during myogenesis. G4s stabilizer pyridostatin impedes embryonic myogenesis, emphasizing the regulatory role of G4s in this process. G4 Cut&Tag sequencing and RNA-seq analyses identify potential G4s and DEGs influencing embryonic myogenesis. Integration of G4 and DEG candidates identifies 32 G4s located in promoter regions capable of modulating gene transcription. WGBS elucidates DNA methylation dynamics during embryonic myogenesis. Coordinating transcriptome data with DNA G4s and DNA methylation profiles constructs a G4-DMR-DEG network, revealing nine interaction pairs. Notably, the NFATC2 promoter region sequence is confirmed to form a G4 structure, reducing promoter mCpG content and upregulating NFATC2 transcriptional activity. CONCLUSIONS: This comprehensive study unravels the first embryonic genomic G4s landscape, highlighting the regulatory role of NFATC2 G4 in orchestrating transcriptional activity through promoter DNA methylation during myogenesis.

IgG4-related sclerosing cholangitis associated with essential thrombocythemia: A case report.

BACKGROUND: The complexity of immunoglobulin G4 (IgG4)-related diseases and their potential connection to hematologic malignancies remains unclear. This article provided a review of the diagnosis and treatment of a patient with IgG4-related sclerosing cholangitis (SC) and essential thrombocythemia (ET), along with an analysis of relevant literature to enhance comprehension of this disease. CASE SUMMARY: A 56-year-old male was admitted to two hospitals with deteriorating jaundice and pruritus prior to hospitalization. Beyond our expectations, the patient was first diagnosed with IgG4-SC and ET with the Janus kinase 2 V617F mutation. Interestingly, the administration of acetate prednisone significantly resulted in improvements in both IgG4-SC and ET. Clinicians need to pay attention to immune disorders and inflammation as they contribute to the development of various disease phenotypes. CONCLUSION: When IgG4-SC is suspected without histopathological evidence, diagnostic therapy and long-term regular follow-up can lead to positive treatment outcomes. Clinicians should be mindful of the potential presence of concurrent hematologic diseases in patients with immune disorders.

G-quadruplexes as pivotal components of cis-regulatory elements in the human genome.

BACKGROUND: Cis-regulatory elements (CREs) are crucial for regulating gene expression, and G-quadruplexes (G4s), as prototypal non-canonical DNA structures, may play a role in this regulation. However, the relationship between G4s and CREs, especially with non-promoter-like functional elements, requires further systematic investigation. We aimed to investigate the associations between G4s and human cCREs (candidate CREs) inferred from the Encyclopedia of DNA Elements (ENCODE) data. RESULTS: We found that G4s are prominently enriched in most types of cCREs, especially those with promoter-like signatures (PLS). The co-occurrence of CTCF signals with H3K4me3 or H3K27ac signals strengthens the association between cCREs and G4s. Genetic variants in G4s, particularly within their G-runs, exhibit higher regulatory potential and deleterious effects compared to cCREs. The G-runs within G4s near transcriptional start sites (TSSs) are more evolutionarily constrained compared to G-runs in cCREs, while those far from the TSS are relatively less conserved. The presence of G4s is often linked to a more favorable local chromatin environment for the activation and execution of regulatory function of cCREs, potentially attributable to the formation of G4 secondary structures. Finally, we discovered that G4-associated cCREs exhibit widespread activation in a variety of cancers. CONCLUSIONS: Our study suggests that G4s are integral components of human cis-regulatory elements, extending beyond their potential role in promoters. The G4 primary sequences are associated with the localization of CREs, while the G4 structures are linked to the activation of these elements. Therefore, we propose defining G4s as pivotal regulatory elements in the human genome.

Several orphan solute carriers functionally identified as organic cation transporters: Substrates specificity compared with known cation transporters.

Organic cations comprise a significant part of medically relevant drugs and endogenous substances. Such substances need organic cation transporters for efficient transfer via cell membranes. However, the membrane transporters of most natural or synthetic organic cations are still unknown. To identify these transporters, genes of 10 known OCTs and 18 orphan solute carriers (SLC) were overexpressed in HEK293 cells and characterized concerning their transport activities with a broad spectrum of low molecular weight substances emphasizing organic cations. Several SLC35 transporters and SLC38A10 significantly enhanced the transport of numerous relatively hydrophobic organic cations. Significant organic cation transport activities have been found in gene families classified as transporters of other substance classes. For instance, SLC35G3 and SLC38A10 significantly accelerated the uptake of several cations, such as clonidine, 3,4-methylenedioxymethamphetamine, and nicotine, which are known as substrates of a thus far genetically unidentified proton/organic cation antiporter. The transporters SLC35G4 and SLC35F5 stood out by their significantly increased choline uptake, and several other SLC transported choline together with a broader spectrum of organic cations. Overall, there are many more polyspecific organic cation transporters than previously estimated. Several transporters had one predominant substrate but accepted some other cationic substrates, and others showed no particular preference for one substrate but transported several organic cations. The role of these transporters in biology and drug therapy remains to be elucidated.

Nuclear PKM2 binds pre-mRNA at folded G-quadruplexes and reveals their gene regulatory role.

Nuclear localization of the metabolic enzyme PKM2 is widely observed in various cancer types. We identify nuclear PKM2 as a non-canonical RNA-binding protein (RBP) that specifically interacts with folded RNA G-quadruplex (rG4) structures in precursor mRNAs (pre-mRNAs). PKM2 occupancy at rG4s prevents the binding of repressive RBPs, such as HNRNPF, and promotes the expression of rG4-containing pre-mRNAs (the "rG4ome"). We observe an upregulation of the rG4ome during epithelial-to-mesenchymal transition and a negative correlation of rG4 abundance with patient survival in different cancer types. By preventing the nuclear accumulation of PKM2, we could repress the rG4ome in triple-negative breast cancer cells and reduce migration and invasion of cancer cells in vitro and in xenograft mouse models. Our data suggest that the balance of folded and unfolded rG4s controlled by RBPs impacts gene expression during tumor progression.

Classical autoimmune hepatitis and the IgG4-associated autoimmune hepatitis in paediatric patients.

The IgG4-associated autoimmune hepatitis (IgG4-AIH) is a newly proposed disease entity characterised by the accumulation of the IgG4-expressing plasma cells in the liver. Its pathophysiology and clinical significance remain unclear and have poor evidence in the paediatric population. Thus, our study aims at comparing the group of paediatric patients with classical AIH and the IgG4-AIH. We carried out a retrospective analysis of 23 children (median age 8.5 years) diagnosed with AIH, who were compared according to the presence of IgG4-positive plasma cells in the liver biopsy. IgG4-AIH was defined if 10 or more IgG4 positive plasma cells/high-power field were found in the biopsy. The presence of the IgG4 component seems to be clinically insignificant. That is why, the conventional immunosuppressive protocol should be considered the standard treatment in the case of the IgG4-associated AIH.

Navigating the Diagnostic Maze: A Case Report of Immunoglobulin G4-Related Disease.

Immunoglobulin G4-related disease (IgG4-RD) is a systemic fibroinflammatory condition characterized by significant infiltration of immunoglobulin G4 (IgG4)-positive plasma cells within affected tissues, with or without elevated serum IgG4 levels. The prevalence of IgG4-RD remains largely undetermined due to diagnostic challenges, as the condition is frequently unrecognized or misdiagnosed. This report describes a case of a 63-year-old man who was ultimately diagnosed with this rare condition after an extensive two-year period of elusive symptoms. Initially presenting with intermittent body pains and fluctuating fever, his condition progressively evolved to include severe right orbital swelling with marked tenderness and ecchymosis, recurrent non-tender nodules on his arm, and diminished vision. A detailed review of his medical history prompted the consideration of IgG4-RD, leading to the measurement of serum human IgG4 levels, which were found to be significantly elevated at 1504 mg/L (normal range: 39.2-864 mg/L). Following his diagnosis, treatment with glucocorticoids (0.6 mg/kg for one month) was initiated, resulting in a positive clinical response. This case emphasizes the critical importance of considering less common conditions in the differential diagnosis of patients presenting with complex, multi-system symptoms.

A Case of Immunoglobulin G4-related Disease Complicated by Atopic Dermatitis Responsive to Upadacitinib Treatment.

Immunoglobulin G4-related disease is mainly treated with glucocorticoids. In many cases, this disease is resistant to glucocorticoids, and their toxicity can be a problem. We encountered a patient with immunoglobulin G4-related disease affecting multiple organs (such as the skin, lung, and lacrimal gland), who had comorbidities, including atopic dermatitis and diabetes. In this case, while glucocorticoid tapering was difficult, the introduction of upadacitinib resulted in remission of both atopic dermatitis and immunoglobulin G4-related disease without glucocorticoid dose escalation. Peripheral blood flow cytometry analysis showed that the proportions of activated non Th1/Th17 cells subset (Th2 cells), follicular helper T cells, and plasmocytes were increased before upadacitinib therapy but all normalised after treatment. Interleukin-4 and interleukin-21 signals are important for the differentiation of CD4+ T cells into type 2 helper T or B cells in the peripheral blood. Our case suggested that inhibition of Janus kinase 1, which mediates these signals, might have contributed to improved pathological conditions in immunoglobulin G4-related disease.