Transcriptome and secretome profiling of sensory neurons reveals sex differences in pathways relevant to insulin sensing and insulin secretion.

Sensory neurons in the dorsal root ganglia (DRG) convey somatosensory and metabolic cues to the central nervous system and release substances from stimulated terminal endings in peripheral organs. Sex-biased variations driven by the sex chromosome complement (XX and XY) have been implicated in the sensory-islet crosstalk. However, the molecular underpinnings of these male-female differences are not known. Here, we aim to characterize the molecular repertoire and the secretome profile of the lower thoracic spinal sensory neurons and to identify molecules with sex-biased insulin sensing- and/or insulin secretion-modulating activity that are encoded independently of circulating gonadal sex hormones. We used transcriptomics and proteomics to uncover differentially expressed genes and secreted molecules in lower thoracic T5-12 DRG sensory neurons derived from sexually immature 3-week-old male and female C57BL/6J mice. Comparative transcriptome and proteome analyses revealed differential gene expression and protein secretion in DRG neurons in males and females. The transcriptome analysis identified, among others, higher insulin signaling/sensing capabilities in female DRG neurons; secretome screening uncovered several sex-specific candidate molecules with potential regulatory functions in pancreatic ß cells. Together, these data suggest a putative role of sensory interoception of insulin in the DRG-islet crosstalk with implications in sensory feedback loops in the regulation of ß-cell activity in a sex-biased manner. Finally, we provide a valuable resource of molecular and secretory targets that can be leveraged for understanding insulin interoception and insulin secretion and inform the development of novel studies/approaches to fathom the role of the sensory-islet axis in the regulation of energy balance in males and females.

Anti­osteopontin autoantibodies in various types of cancer.

The aberrant processing of biomolecules by cancer cells may give rise to autoimmune phenomena. The metastasis gene osteopontin is alternatively spliced only in transformed cells, and the variants promote tumor progression. They may also serve as tumor­associated antigens, and their neutralization by autoantibodies could favorably affect prognosis. A competitive solid­phase ELISA format was applied to determine reactivity toward recombinant osteopontin in human serum or plasma samples. Approximately 35% of thyroid cancer patients and 15% of other cancer patients were found to harbor autoantibodies directed to osteopontin variants, averaging 21% of patients across all cancers studied. The reactivity of the autoantibodies was consistent with the differential appearance of splice variants in individual malignancies. In thyroid cancer, autoantibodies were found to be more frequently associated with a milder form of the disease. The junctions of osteopontin splice variants produced by cancers represent tumor­associated neo­epitopes. Whereas the uniqueness of their sequences renders the acquisition of tolerance during immune maturation improbable, their immunogenicity is predicted to be low. The rare occurrence of antibodies to either osteopontin­b or osteopontin­c suggests that the breaking of tolerance to full­length osteopontin is more prevalent in tumor autoimmunity than a reaction to a poorly immunogenic neo­epitope.