Fig 1: Prosaposin (PSAP) and PS18 as a novel myokine enriched in 5xFAD;cTFEB;HSACre mice that recapitulates enhancement of neurotrophic signaling and synaptic integrity. A, B Immunoblots for PSAP and 3x-FLAG in skeletal muscle (A) and for PSAP and saposin-C in cortex (B). Transgenic 3x-FLAG-TFEB protein weighs ∼75 kDa. The arrow highlights the TFEB protein; the asterisk (*) highlights a non-specific band. Densitometry quantification normalized by Total StainFree protein lane densitometry is shown below. C Enzyme-linked immunosorbent assay (ELISA) for PSAP in peripheral plasma of an 8-month-old female mice. D Schematic illustration of PS18 or dimethyl sulfoxide (DMSO) subcutaneous injection in healthy 3-month-old C57/B6L male mice and subsequent isolation of cortical protein lysates and synaptosome-enriched fractions. E Immunoblot for pro and mature BDNF in cortical protein lysates from PS18- or DMSO-injected C57/B6L male mice. Densitometry quantification for proBDNF and BDNF normalized by Total StainFree protein lane densitometry is shown below. F Immunoblots for SNAP25 and PSD95 in cortical synaptosome-enriched fractions from PS18- or DMSO-injected C57/B6L male mice. Densitometry quantification normalized to β tubulin is shown below. Statistical comparison was performed using one-way ANOVA and post hoc multiple comparisons or independent t-tests, * p < 0.05, ** p < 0.01, ***p < 0.001; n.s., non-significant. Data is represented as mean ± SEM