Stemness-related genes revealed by single-cell profiling of naïve and stimulated human CD34+ cells from CB and mPB.

BACKGROUND: Hematopoietic stem cells (HSCs) from different sources show varied repopulating capacity, and HSCs lose their stemness after long-time ex vivo culture. A deep understanding of these phenomena may provide helpful insights for HSCs. METHODS: Here, we applied single-cell RNA-seq (scRNA-seq) to analyse the naïve and stimulated human CD34+ cells from cord blood (CB) and mobilised peripheral blood (mPB). RESULTS: We collected over 16 000 high-quality single-cell data to construct a comprehensive inference map and characterised the HSCs under a quiescent state on the hierarchy top. Then, we compared HSCs in CB with those in mPB and HSCs of naïve samples to those of cultured samples, and identified stemness-related genes (SRGs) associated with cell source (CS-SRGs) and culture time (CT-SRGs), respectively. Interestingly, CS-SRGs and CT-SRGs share genes enriched in the signalling pathways such as mRNA catabolic process, translational initiation, ribonucleoprotein complex biogenesis and cotranslational protein targeting to membrane, suggesting dynamic protein translation and processing may be a common requirement for stemness maintenance. Meanwhile, CT-SRGs are enriched in pathways involved in glucocorticoid and corticosteroid response that affect HSCs homing and engraftment. In contrast, CS-SRGs specifically contain genes related to purine and ATP metabolic process, which is crucial for HSC homeostasis in the stress settings. Particularly, when CT-SRGs are used as reference genes for the construction of the development trajectory of CD34+ cells, lymphoid and myeloid lineages are clearly separated after HSCs/MPPs. Finally, we presented an application through a small-scale drug screening using Connectivity Map (CMap) against CT-SRGs. A small molecule, cucurbitacin I, was found to efficiently expand HSCs ex vivo while maintaining its stemness. CONCLUSIONS: Our findings provide new perspectives for understanding HSCs, and the strategy to identify candidate molecules through SRGs may be applicable to study other stem cells.

Sjogren's syndrome complicating pancytopenia, cerebral hemorrhage, and damage in nervous system: A case report and literature review.

RATIONALE: Sjogren's syndrome(SS) is a chronic autoimmune disease, which damages exocrine glands especially salivary and lacrimal glands, with xerostomia and xerophthalmia as common symptoms. PATIENT CONCERNS: We report a case of a 49-year-old woman presented with pancytopenia. Her laboratory examinations lead us diagnose her as Sjogren's syndrome complicating pancytopenia. She had neurological symptoms during her treatment, which represent only 4.5% of Sjogren's syndrome complicating damage in nervous system. DIAGNOSES: Sjogren's syndrome complicating pancytopenia. INTERVENTIONS: Dexamethasone (40mg QD for 4 days) and immunoglobulin (25g QD for 2 days) were administered for intensive treatment followed by oral methylprednisolone 40mg QD as maintenance treatment. Total glucosides of paeony 0.6g TID and danazol 0.2g BID per os were given. We also gave her Piperacillin-tazobactam and moxifloxacin for anti-infection and Fluconazole for anti-fungal therapy, as well as other supportive treatments. OUTCOMES: Follow-up of the patient observed the normalization of peripheral blood cell count, immunity indices and neurological examinations 6 months after discharge. LESSONS: For patients presented with blood system abnormalities unilineage or multiple-lineage cytopenia in particular, history investigations and relevant examinations should be considered to exclude the existence of autoimmune diseases like Sjogren's syndrome.