Fig 2: Tmem106b Reduction Does Not Rescue Most Lysosomal Phenotypes of Grn+/− Mice. Frontal cortex samples from 5- to 6-month-old Grn+/− mice exhibited no differences from wild-type in LAMP-1 levels (a) or GCase activity (c), but increased HexA activity (b, **** = ANOVA effect of Grn, p < 0.0001) and Gusb activity (d, ANOVA effect of Grn, p = 0.0009). Tmem106b reduction had no significant effect on LAMP-1, HexA, or GCase in 5- to 6-month-old mice, but significantly reduced Gusb activity (ANOVA effect of Tmem106b, p = 0.0031, * = p < 0.05 by Tukey’s post-hoc test). Frontal cortex samples from 12-month-old Grn+/− mice exhibited increased LAMP-1 levels (e, ** = ANOVA effect of Grn, p = 0.0072), HexA activity (f, **** = ANOVA effect of Grn, p < 0.0001), GCase activity (g, * = ANOVA effect of Grn, p = 0.0179), and Gusb activity (h, ANOVA effect of Grn, p < 0.0001). As in the younger mice, Tmem106b reduction had no significant effect on LAMP-1, HexA, or GCase in 12 month-old mice, but significantly reduced Gusb activity (ANOVA effect of Tmem106b, p = 0.0010, * = p < 0.05, **** = p < 0.0001 by Tukey’s post-hoc test). n = 12 mice per group for 5- to 6-month-old mice and 11–12 mice per group for 12-month-old mice

Fig 3: Tmem106b Reduction Does Not Rescue the Social Dominance Deficits of Grn+/− Mice. When paired against Grn+/+:Tmem+/+ mice, Grn+/−:Tmem+/+ mice exhibited the expected losing phenotype as shown by both wins per genotype (a, Binomial test, p = 0.0053, n = 133 matches) and winning percentage (b, Mann-Whitney test, p = 0.0016, n = 45–46 mice per genotype). Grn+/−:Tmem+/− mice also exhibited a losing phenotype versus Grn+/+:Tmem+/+ mice (c, Binomial test, p < 0.0001, d, Mann-Whitney test, p < 0.0001, n = 30 mice per genotype). Tmem106b reduction did not i change social dominance between either Grn+/− mice(h, Binomial test, p = 0.6879, i, Mann-Whitney test, p = 0.6198, n = 33 mice per genotype) or Grn+/+ mice (f, Binomial test, p > 0.9999 g, Mann-Whitney test, p = 0.6914, n = 11 mice per genotype)

Fig 4: Positive correlation between TMEM106B and neurofilament, heavy polypeptide mRNA levels. Neurofilament, heavy polypeptide (NFH), glial fibrillary acidic protein (GFAP), and RNA-binding protein, fox-1 homolog (Caenorhabditis elegans)-3 (RBFOX3, NEUN) mRNA expression levels were studied by quantitative reverse transcriptase-polymerase chain reaction (qPCR) in human brain tissues derived from a reference of the human frontal cortex (REF), four non-neurological causes (NC) cases, six amyotrophic lateral sclerosis (ALS) cases, four Parkinson’s disease PD cases, and seven AD cases. The expression levels were standardized against those of G3PDH. (a) NFH expression. (b) GFAP expression. (c) NEUN expression. (d) Pearson’s correlation between TMEM106B and NFH mRNA levels. Pearson’s correlation coefficient indicates 0.496 (P = 0.0221).

Fig 5: Knockdown of Tmem106b with ASOs rescues endolysosomal trafficking defects. (A) Representative images of mutant CHMP2B neurons treated with 5 µM of the indicated ASOs for 7 days loaded with LysoTracker®. Scale bar = 10 µm. (B) Representative kymographs from LysoTracker® live cell recordings of neurons labelled with the indicated ASOs. Vertical scale bar = 20 s, horizontal scale bar = 10 µm. (C) Quantification of kymographs of LysoTracker® movement in DIV 14 mutant CHMP2B cortical cultures following treatment with the indicated ASOs. n = 4 with five to seven neurons per n. (D) Quantification of the number of LysoTracker® labelled structures in the sections of neurite chosen for kymograph analysis. n = 4 with five to seven neurons per n. One-way ANOVA with Newman-Keuls multiple comparison test, **P < 0.01.