The cellular modifier MOAG-4/SERF drives amyloid formation through charge complementation (2021)
Figure 6

Figure 6. Neutralizing charge of the endogenous SERF ortholog MOAG-4 is sufficient to suppress protein aggregation and toxicity in C. elegans.

(A) Mutations and Average Net charge distribution of wild-type MOAG-4, MOAG-4 charge mutant and MOAG-4 control mutant.

(B) Representative images of Q40 and Q40;moag-4 charge mutant animals. Scale bar, 75 mm. (C) Representative quantification of the number of aggregates in Q40 worms with moag-4 deletion or expression of either wild-type moag-4, moag-4 charge mutant or moag-4 ctrl mutant. The results shown are representative experiments of three biological replicates of n=20 worms in L4 stage. Data are represented as mean ± SD and significance was calculated using a one-way ANOVA, followed by a post-hoc Bonferroni multiple comparisons test. ****p < 0.0001.

(D) Representative TCSPC-FLIM images from the indicated strains. The dashed lines mark the retro vesicular ganglion and arrowheads indicate aggregates. Scale bar is 50 µm.

(E) Number of aggregates per retro vesicular ganglion from three independent cohorts of the indicated Aβ1-42 strains with moag-4 deletion mutant (del (tm4909)) n=11, moag-4 control mutant (ctrl mutant) n=12, moag-4 charge mutant (charge mutant) n=17, and wild-type n=15. Data are represented as mean ± SD. One-way ANOVA + Bonferroni post-hoc test for significance (* p < 0.05, **** p < 0.0001).

(F) Cumulative survival probability of the indicated strains (N2: n = 120; Aβ1-42: n = 120; moag-4 control mutant (ctrl mutant): n = 105; moag-4 control mutant; Aβ1-42 (ctrl mutant; Aβ1-42): n = 95; moag-4 charge mutant (charge mutant): n = 100; moag-4 charge mutant; Aβ1-42 (charge mutant; Aβ1-42): n = 90. Significance was tested by Mantel-Cox test (** p < 10-4, *** p < 10-6).

(G) Fractions of nematodes in the indicated developmental stages after three days at 20°C starting from egg laying. Aβ1-42: ℕ = 6 (analysed cohorts), n = 16 - 78 (animals per cohort); ctrl mutant: ℕ = 3, n = 42 - 191; ctrl mutant; Aβ1-42: ℕ = 6, n = 34 - 70; charge mutant: ℕ = 3, n = 46 - 139; charge mutant; Aβ1-42: ℕ = 6, n = 26 - 125. Depicted significance was tested between L4-stage groups with ANOVA + Bonferroni post-hoc test (*** p < 0.001). Depicted is mean ± SD.

(H) Pathogen avoidance reaction of indicated nematode strains from Serratia marcescens Db11 or Escherichia coli OP50. Dots represent a single cohort (10 - 15 individual animals/cohort), bars display mean across cohorts ± SD. S. marcescens Db11 - N2: ℕ = 11 (cohorts) , N = 3 (experimental runs), n = 4 (technical replicates); Aβ1-42: ℕ = 7, N = 2, n = 4; tol-1 mutant: ℕ = 9, N = 3, n = 4; ctrl mutant: ℕ = 7, N = 2, n = 4; ctrl mutant; Aβ1-42: ℕ = 7, N = 2, n = 4; charge mutant: ℕ = 8, N = 2, n = 4; charge mutant; Aβ1-42: ℕ = 7, N = 2, n = 4. Significance was tested with ANOVA + Bonferroni post-hoc test (*** p < 0.001).E. coli OP50 - N2: ℕ = 8, N = 3, n = 4; Aβ1-42: ℕ = 7, N = 2, n = 4; tol-1 mutant: ℕ = 8, N = 3, n = 4; ctrl mutant: ℕ = 5, N = 2, n = 4; ctrl mutant; Aβ1-42: ℕ = 6, N = 2, n = 4; charge mutant: ℕ = 5, N = 2, n = 4; charge mutant; Aβ1-42: ℕ = 6, N = 2, n = 4.