NOTCH and Graft-Versus-Host Disease

Lower expression of NOTCH components in peripheral blood mononuclear cells of allogeneic hematopoietic cell transplant patients

INTRODUCTION

Chronic graft-versus-host disease (cGvHD) not only remains the main cause of late mortality after allogeneic hematopoietic cell transplant, but also has the capacity of causing severe organ impairment in those who survive. The Notch, a highly conserved ligand-receptor pathway, is involved in many immunological processes, including inflammatory and regulatory responses. Recently, mouse models have shown that the blockage of canonical Notch signaling prevents GvHD.

OBJECTIVE AND METHOD

Due to the lack of data on the Notch pathway in human chronic GvHD, we sought to study the expression of NOTCH components in primary samples of patients who received allo-HCT and presented active cGvHD or a long-term clinical tolerance to cGvHD.

RESULTS

Our results showed a significantly lower expression of NOTCH components in both groups that received allo-HCT, independently of their cGvHD status, when compared to healthy controls.

CONCLUSION

Moreover, there were no differences in gene expression levels between the active cGvHD and clinically tolerant groups. To our knowledge, this is one of the first studies performed in human primary samples and our data indicate that much remains to be learned regarding NOTCH signaling as a new regulator of GvHD.

Recent advances in graft-versus-host disease

Acute and chronic graft-versus-host disease (GVHD) continue to present a significant challenge to physicians, accounting for considerable haematopoietic stem cell transplant (HSCT)-related morbidity and mortality, particularly those patients with steroid-refractory disease. In this review, we discuss recent advances in understanding the underlying pathophysiology, prevention and management of acute and chronic GVHD. Barriers to progress include the difficulty in obtaining high-quality evidence with sufficient patient numbers to identify optimal preventative and treatment strategies, with the heterogeneity of multiple patient, donor, graft and transplant-related factors, in addition to limited availability of human tissue to study the underlying pathophysiology, particularly in steroid-refractory disease. Continued collaborative efforts to improve our understanding of the pathophysiology involved, particularly in steroid-refractory disease, identification of biomarkers to permit risk stratification, and further well-designed randomised clinical trials are essential to help physicians determine optimal GVHD preventative and treatment strategies for each individual patient.

Notch signaling pathway: architecture, disease, and therapeutics

The NOTCH gene was identified approximately 110 years ago. Classical studies have revealed that NOTCH signaling is an evolutionarily conserved pathway. NOTCH receptors undergo three cleavages and translocate into the nucleus to regulate the transcription of target genes. NOTCH signaling deeply participates in the development and homeostasis of multiple tissues and organs, the aberration of which results in cancerous and noncancerous diseases. However, recent studies indicate that the outcomes of NOTCH signaling are changeable and highly dependent on context. In terms of cancers, NOTCH signaling can both promote and inhibit tumor development in various types of cancer. The overall performance of NOTCH-targeted therapies in clinical trials has failed to meet expectations. Additionally, NOTCH mutation has been proposed as a predictive biomarker for immune checkpoint blockade therapy in many cancers. Collectively, the NOTCH pathway needs to be integrally assessed with new perspectives to inspire discoveries and applications. In this review, we focus on both classical and the latest findings related to NOTCH signaling to illustrate the history, architecture, regulatory mechanisms, contributions to physiological development, related diseases, and therapeutic applications of the NOTCH pathway. The contributions of NOTCH signaling to the tumor immune microenvironment and cancer immunotherapy are also highlighted. We hope this review will help not only beginners but also experts to systematically and thoroughly understand the NOTCH signaling pathway.

Highlighting the interaction between immunomodulatory properties of mesenchymal stem cells and signaling pathways contribute to Graft Versus Host Disease management

Background Allogeneic hematopoietic stem cell transplantation (Allo-HSCT) has been increasingly used as a therapeutic approach for hematological malignancies. Several potential strategies have been developed for treating or preventing allo-HSCT complications, specifically graft-versus-host disease (GVHD). GVHD could significantly affect the morbidity and mortality of patients after allo-HSCT. Curative treatment and prophylaxis regimens for GVHD could reduce GVHD incidence and improve survival rate. Among these therapeutic strategies, mesenchymal stem cell (MSCs) mediated immunomodulation has been explored widely in clinical trials. MSCs immunomodulation ability in GVHD correlates with the interactions of MSCs with innate and adaptive immune cells. However, signaling pathways responsible for MSCs' impact on GVHD regulation, like JAK/STAT, NOTCH, MAPK/ERK, and NFκβ signaling pathways, have not been clearly described yet. This review aims to illuminate the effect of MSCs-mediated immunomodulation in GVHD management after allo-HSCT representing the role of MSCs therapy on signaling pathways in GVHD. Conclusion MSCs could potentially modulate immune responses, prevent GVHD, and improve survival after allo-HSCT. Previous studies have investigated different signaling pathways' contributions to MSCs immunoregulatory ability. Accordingly, targeting signaling pathways components involved in MSCs related GVHD regulation is proven to be beneficial.

Fluorescence in situ hybridization-based confirmation of acute graft-vs-host disease diagnosis following liver transplantation: A case report

BACKGROUND

Although acute graft-vs-host disease (aGvHD) is a rare complication of liver transplantation, it is poorly understood and has an extremely high mortality rate. No standardized diagnostic criteria or treatment regimens currently exist.

CASE SUMMARY

The present study investigated the etiology, diagnosis, and treatment of aGvHD following liver transplantation. Presentation, diagnosis, disease course, histology, and treatment of an aGvHD case are reported, and associated literature is reviewed. A 64-year-old female required LTx due to primary biliary cirrhosis. The donor was a 12-year-old male. Three weeks following liver transplantation, the recipient developed pyrexia, diarrhea, rashes, and antibiotic-unresponsive pancytopenia. Clinical symptoms together with laboratory investigations suggested a diagnosis of aGvHD, which was confirmed via peripheral blood fluorescent in situ hybridization. Donor XY chromosome fluorescent in situ hybridization indicating early chimerism achieved 93% sensitivity in the detection of GvHD. Existing immunosuppressants were discontinued, and high-dose intravenous methylprednisolone was initiated along with antibiotics. While diarrhea resolved, the patient’s general condition continued to deteriorate until demise due to multi-system organ failure at 37 d post-liver transplantation. This case illustrates the life-threatening nature of aGvHD.

CONCLUSION

Herein, we have summarized a post-LTx aGvHD case and reviewed associated literature in order to increase awareness and provide potentially risk-mitigating recommendations.

Circulating miR-455-3p, miR-5787, and miR-548a-3p as potential noninvasive biomarkers in the diagnosis of acute graft-versus-host disease: a validation study

Currently, acute graft-versus-host disease (aGVHD) diagnosis is based on clinical features and pathological findings. Until now, there is no non-invasive diagnostic test for aGVHD. MicroRNAs may act as promising predictive, diagnostic, or prognostic biomarkers for aGVHD. The purpose of the current study was to validate circulating microRNAs as diagnostic biomarkers to assist clinicians in promptly diagnosing aGVHD, so that treatment can be initiated earlier. In the present study, we evaluated six microRNAs (miR-455-3p, miR-5787, miR-6729-5p, miR-6776-5p, miR-548a-3p, and miR-6732-5p) selected from miRNA array data in 40 aGVHD patients compared to 40 non-GVHD patients with RT-qPCR. Target genes of differentially expressed microRNAs (DEMs) were predicted using Targetscan, miRanda, miRDB, miRWalk, PICTAR5, miRmap, DIANA, and miRTarBase algorithms, and their functions were analyzed using EnrichNet, Metascape, and DIANA-miRPath databases. The expressions of plasma miR-455-3p and miR-5787 were significantly downregulated, whereas miR-548a-3p was significantly upregulated in aGVHD patients compared to non-GVHD patients. Moreover, DEMs showed potentially high diagnostic accuracy for aGVHD. In silico analysis of DEMs provided valuable information on the role of DEMs in GVHD, immune regulation, and inflammatory response. Our study suggested that miR-455-3p, miR-5787, and miR-548a-3p could be used as potential noninvasive biomarkers in the diagnosis of aGVHD in addition to possible therapeutic targets in aGVHD.

Blockade of the Notch1/Jagged1 pathway in Kupffer cells aggravates ischemia-reperfusion injury of orthotopic liver transplantation in mice

Liver ischemia-reperfusion injury (IRI) represents a risk factor for early graft dysfunction and an obstacle to expanding donor pool in orthotopic liver transplantation (OLT). Kupffer cells (KCs) are the largest antigen-presenting cell (APC) group and the primary modulators of inflammation in liver tissues. The vital role of Notch1/Jagged1 pathway in mouse OLT model has been reported, however, its potential therapeutic mechanism is unknown. Here, we made use of short hairpin RNA-Jagged1 and AAV-Jagged1 to explore the effects of Notch1/Jagged1 pathway in OLT. In vitro, blockade of Notch1/Jagged1 pathway downregulated the expression of Hairy and enhancer of split-1 (Hes1) gene, which in turn increased the proinflammatory effects of KCs. Moreover, the anti-inflammatory effects of Notch1/Jagged1 pathway were induced by inhibiting Hes1/gene of phosphate and tension/protein kinase B/Toll-like receptor 4/nuclear factor kappa B (Hes1/PTEN/AKT/TLR4/NF-κB) axis in KCs. In vivo, we used a well-established mouse model of OLT to mimic clinical transplantation. Mice were stochastically divided into 6 groups: Sham group (n = 15); Normal saline (NS) group (n = 15); Adeno-associated virus-green fluorescent protein (AAV-GFP) group (n = 15); AAV-Jagged1 group (n = 15); Clodronate liposome (CL) group (n = 15); CL+AAV-Jagged1 group (n = 15) . After OLT the liver damage in AAV-Jagged1 group were significantly accentuated compared to the AAV-GFP group. While blockade of Jagged1 aftet clearence of KCs by CL would not lead to further liver injuries. Taken together, our study demonstrated that blockade of Notch1/Jagged1 pathway aggravates inflammation induced by lipopolysaccharide (LPS) via Hes1/PTEN/AKT/TLR4/NF-κB in KCs, and the blockade of Notch1/Jagged1 pathway in donor liver increased neutrophil/macrophage infiltration and hepatocellular apoptosis, which suggested the function of Notch1/Jagged1 pathway in mouse OLT and highlighted the protective function of Notch1/Jagged1 pathway in liver transplantation.