Lysosome Dysfunction Contributes to Myeloproliferative Neoplasm Development Via Oncostatin-M Dependent Inflammation

Lysosomal storage disorder (LSD) is a congenital metabolic disorder caused by gene mutations involved in lysosomal function. Gene defects encoding hydrolases and transporters and enzyme activators are found in some LSD's, leading to macro molecular accumulation in the late endocytic system. It is suggested that lysosomal function is important in cancer as it can promote the development of malignant cells via various mechanism: widespread cytokine dysregulation, aberrant inflammatory and immune responses, endoplasmic reticulum and oxidative stress, proliferative signaling, degradation of extracellular matrix, and induction of Integrin-β4-mediated cell migration and invasion.

Using germline analysis of ICGC-PCAWG data, we recently found that the incidence of myeloproliferative neoplasia (MPN) is significantly increased in the presence of LSD putative pathogenic germline variant (PPGV). Based on this, we generated multi-omics data (Whole Exome sequencing, Whole Transcriptome sequencing, Single cell RNA sequencing) using MPN patient's samples with both LSD PPGV carrier and non-carrier to elucidate the pathophysiological association between LSD PPGV and MPN. Various functional analyzes were performed with WTS to identify a wide range of functional differences by dividing into two groups. We analyzed Single cell RNA data to confirm the above hypothesis at the single cell level.

Using WTS, the cytokine and chemokine receptor-ligand gene, pro-inflammatory gene, and inflammation-related transcription factor and pathway were up regulated in the LSD carrier group compared to the LSD non carrier group. In addition, the network modules showing inflammation-related functions were differentially activated in the LSD non-carrier group compared to the LSD carrier group in the differential co-expressed network analysis. Beside JAK2, MPL and CALR mutations, well known main drivers of MPN, chronic inflammation has also been reported as a key player in the onset of MPN. Therefore, we hypothesized that cytokine dysregulation, which is specific to LSD PPGV retention, pre-dispositions the inflammatory milieu, affecting several aspects, including MPN disease onset, progression, and symptoms.

From the Single-cell RNA data of MPN patients, differential expression analysis and gene set enrichment analysis confirmed that a number of cytokine genes and inflammation-related pathways were up regulated in LSD carrier group MPN compared to LSD non carrier group MPN in monocytes among several immune cells profiled through functionality analysis. Several types of cytokine and chemokine receptor-ligand genes showed a statistically significantly high interaction (Oncostatin-M(OSM)^IL6ST*LIFR, CXCL2,3,8,10,11^{CXCR2,CXCR3,ACKR1}, CCL2,3,7^{CCR2,CCR1,CCR5,ACKR1})in the cell-cell interaction analysis. We performed Gene Regulatory Network (GRN) analysis to check whether the transcription factor associated with OSM^IL6ST*LIFR was activated. Accordingly, CEBPB and STAT1, known as downstream regulators of OSM^IL6ST*LIFR, were activated in LSD carrier MPN compared to LSD non carrier MPN.

In summary, we demonstrated that the cytokine-family candidate receptor-ligand gene identified in monocytes may contribute to the pathogenesis of MPN by dysregulation of cytokines and induction of inflammatory environment in the presence of LSD PPGV. Especially OSM, known as a key regulator of cancer development and regulating the production of cytokines and chemokines, could be one of the molecules highly expressed with MPNs bearing LSD PPGV. Future studies will enable to understand the pathophysiology of OSM in MPN patients bearing LSD PPGV.

Kim:Agenus: Consultancy; Nextcure: Research Funding. Koh:Sanofi Genzyme: Research Funding. Yoon:Chugai Pharmaceutical: Consultancy; Janssen Pharmaceutical: Consultancy; Celgene: Consultancy; Astellas Pharma: Consultancy; Kyowa Kirin: Research Funding; Novartis: Consultancy; Amgen: Consultancy; Roche-Genetech: Research Funding; Yuhan Pharmaceutical: Research Funding; Tikaros: Consultancy; Takeda: Consultancy.