Single-cell RNA-seq analysis identifies meniscus progenitors and reveals the progression of meniscus degeneration. Single-cell RNA-seq analysis identifies meniscus progenitors and reveals the progression of meniscus degeneration

We identified seven clusters in healthy human meniscus, including five empirically-defined populations and two novel populations. Pseudotime analysis showed EC and FCP existed at the pseudospace trajectory start. MCAM (CD146) was highly expressed in two clusters. CD146+ meniscus cells differentiated into osteoblasts and adipocytes and formed colonies. We identified changes in the proportions of degenerated meniscus cell clusters and found a cluster specific to degenerative meniscus with progenitor cell characteristics. The reconstruction of four progenitor cell clusters indicated that FCP differentiation into DegP was an aberrant process. Interleukin-1β stimulation in healthy human meniscus cells decreased CD146+ cells and increased CD318+ cells, while TGFβ1 attenuated the increase in CD318+ cells in degenerated meniscus cells. Overall design: scRNA-seq was used to identify cell subsets and their gene signatures in healthy human and degenerated meniscus cells

本研究在健康人类半月板组织中鉴定出7个细胞簇，其中包含5个经实验界定的细胞群与2个全新发现的细胞群。伪时序分析（Pseudotime analysis）显示，EC与FCP位于伪空间轨迹的起始位点。细胞黏附分子MCAM（CD146）在两个细胞簇中呈高表达。CD146阳性半月板细胞可分化为成骨细胞与脂肪细胞，并能形成细胞集落。本研究分析了退变半月板细胞簇的比例变化，并发现了一个兼具祖细胞特征的退变半月板特异性细胞簇。对4个祖细胞簇的重构分析表明，FCP向DegP的分化属于异常分化过程。用白细胞介素-1β（Interleukin-1β）刺激健康人类半月板细胞，可降低CD146阳性细胞的占比并提升CD318阳性细胞的数量；而转化生长因子-β1（TGFβ1）可抑制退变半月板细胞中CD318阳性细胞的数量上升。实验设计方案：采用单细胞RNA测序（scRNA-seq）技术，对健康人类与退变人类半月板组织的细胞亚群及其基因特征进行鉴定。