Advanced metastatic cancer poses utmost clinical challenges and may present molecular and cellular features distinct from an early-stage cancer. Herein, we present single-cell transcriptome profiling of metastatic lung adenocarcinoma, the most prevalent histological lung cancer type diagnosed at stage IV in over 40% of all cases. From 208,506 cells populating the normal tissues or early to metastatic stage cancer in 44 patients, we identify a cancer cell subtype deviating from the normal differentiation trajectory and dominating the metastatic stage. In all stages, the stromal and immune cell dynamics reveal ontological and functional changes that create a pro-tumoral and immunosuppressive microenvironment. Normal resident myeloid cell populations are gradually replaced with monocyte-derived macrophages and dendritic cells, along with T-cell exhaustion. This extensive single-cell analysis enhances our understanding of molecular and cellular dynamics in metastatic lung cancer and reveals potential diagnostic and therapeutic targets in cancer-microenvironment interactions.

Objective Human Lyme arthritis caused by Borrelia burgdorferi is characterized by an inflammatory infiltrate that consists mainly of neutrophils and T cells. This study was undertaken to evaluate the role of the innate and acquired immune responses elicited by the neutrophil‐activating protein A (NapA) of B burgdorferi in patients with Lyme arthritis. Methods Serum anti‐NapA antibodies were measured in 27 patients with Lyme arthritis and 30 healthy control subjects. The cytokine profile of synovial fluid T cells specific for NapA was investigated in 5 patients with Lyme arthritis. The cytokine profile induced by NapA in neutrophils and monocytes was also investigated. Results Serum anti‐NapA antibodies were found in 48% of the patients with Lyme arthritis but were undetectable in the healthy controls. T cells from the synovial fluid of patients with Lyme arthritis produced interleukin‐17 (IL‐17) in response to NapA. Moreover, NapA was able to induce the expression of IL‐23 in neutrophils and monocytes, as well as the expression of IL‐6, IL‐1β, and transforming growth factor β (TGFβ) in monocytes, via Toll‐like receptor 2. Conclusion These findings indicate that NapA of B burgdorferi is able to drive the expression of IL‐6, IL‐1β, IL‐23, and TGFβ by cells of the innate immune system and to elicit a synovial fluid Th17 cell response that might play a crucial role in the pathogenesis of Lyme arthritis.

We have identified missense mutations at conserved amino acids in the PRPS1 gene on Xq22.3 in two families with a syndromic form of inherited peripheral neuropathy, one of Asian and one of European descent. The disease is inherited in an X-linked recessive manner, and the affected male patients invariably develop sensorineural hearing loss of prelingual type followed by gating disturbance and visual loss. The family of European descent was reported in 1967 as having Rosenberg-Chutorian syndrome, and recently a Korean family with the same symptom triad was identified with a novel disease locus CMTX5 on the chromosome band Xq21.32-q24. PRPS1 (phosphoribosyl pyrophosphate synthetase 1) is an isoform of the PRPS gene family and is ubiquitously expressed in human tissues, including cochlea. The enzyme mediates the biochemical step critical for purine metabolism and nucleotide biosynthesis. The mutations identified were E43D, in patients with Rosenberg-Chutorian syndrome, and M115T, in the Korean patients with CMTX5. We also showed decreased enzyme activity in patients with M115T. PRPS1 is the first CMT gene that encodes a metabolic enzyme, shedding a new light on the understanding of peripheral nerve-specific metabolism and also suggesting the potential of PRPS1 as a target for drugs in prevention and treatment of peripheral neuropathy by antimetabolite therapy.