We used single cell RNA-Seq to examine molecular heterogeneity in multiple myeloma (MM) in 597 CD138 positive cells from bone marrow aspirates of 15 patients at different stages of disease progression. 790 genes were selected by coefficient of variation (CV) method and organized cells into four groups (L1–L4) using unsupervised clustering. Plasma cells from each patient clustered into at least two groups based on gene expression signature. The L1 group contained cells from all MGUS patients having the lowest expression of genes involved in the oxidative phosphorylation, Myc targets, and mTORC1 signaling pathways (p < 1.2 × 10−14). In contrast, the expression level of these pathway genes increased progressively and were the highest in L4 group containing only cells from MM patients with t(4;14) translocations. A 44 genes signature of consistently overexpressed genes among the four groups was associated with poorer overall survival in MM patients (APEX trial, p < 0.0001; HR, 1.83; 95% CI, 1.33–2.52), particularly those treated with bortezomib (p < 0.0001; HR, 2.00; 95% CI, 1.39–2.89). Our study, using single cell RNA-Seq, identified the most significantly affected molecular pathways during MM progression and provided a novel signature predictive of patient prognosis and treatment stratification.

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1. The purpose of the present study was to examine lung water transport properties and the expression and regulation of the alveolar endothelial water channel aquaporin (AQP)-1 and the epithelial water channel AQP-5 in aged mouse lung using gene expression analysis and water permeability measurements. 2. In aged (20-24-month-old) mice, AQP-1 and AQP-5 mRNA expression decreased by 55.5 and 50.3%, respectively, compared with that in young (8-10-week-old) mice (P < 0.01). In addition, AQP-1 and AQP-5 protein expression decreased in aged mice by 36.9 and 44.6%, respectively, compared with that in young mice (P < 0.01). 3. The osmotically driven water transport rate between the airspace and capillary compartments was reduced by 31.7% in aged mice compared with young mice (2.8 +/- 0.3 vs 4.1 +/- 0.3 mg/s, respectively; P < 0.01). The hydrostatically driven lung water accumulation rate in response to a 10 cmH(2)O increase in pulmonary artery pressure was also reduced in aged mice by 21.9% compared with young mice (0.32 +/- 0.06 vs 0.41 +/- 0.04 mg/s, respectively; P < 0.01). 4. There was a 62.7% decrease in serum glucocorticoids in aged mice compared with young mice (67.6 +/- 26.8 vs 181.3 +/- 44.4 nmol/L, respectively; P < 0.01). In vivo administration of dexamethasone (4 mg/kg) for 5 consecutive days to aged mice increased lung AQP-1 mRNA and protein expression by 2.1 +/- 0.1 fold (P < 0.01) and 1.8 +/- 0.2 fold (P < 0.01), respectively. Accordingly, osmotically and hydrostatically driven water transport rates increased by 35.6% (P < 0.01) and 31.2% (P < 0.01), respectively. 5. The present study provides the first evidence of altered lung water transport associated with downregulation of AQPs in aged lung. Blood glucocorticoid hormone levels are important to maintain normal AQP-1 expression in the lung microvascular endothelium. Corticosteroid-induced AQP-1 upregulation may contribute to the role of corticosteroids in accelerating oedema clearance in aged lung.