Figure 2. LPS- and PS-induced in situ podocyte Ca²⁺ transients are reduced in isolated glomeruli from Trpc5-KO mice.

(A) Approach for imaging Ca²⁺ in podocytes in situ on intact, acutely isolated mouse glomeruli. Podocytes — located on the exterior surface of the isolated glomerulus, as shown — were efficiently loaded with Fura-2 and displayed measurable changes in Ca²⁺ in response to various stimuli. (B) LPS mediated Ca²⁺ influx (arrows) in glomeruli of WT mice, but the response was attenuated in Trpc5-KO glomeruli. (C) Quantification of peak transient amplitude (at Δt = 1 min) revealed a significantly greater response in WT (n = 24) versus Trpc5-KO (n = 10) glomeruli, attributed to TRPC5-mediated Ca²⁺ influx. (D) PS mediated Ca²⁺ influx (arrows) in WT glomeruli, but the response was attenuated in Trpc5-KO glomeruli. (E) Quantification of peak transient amplitude revealed a significantly greater response in WT versus Trpc5-KO glomeruli (n = 19 per group), attributed to TRPC5-mediated Ca²⁺ influx. Original magnification, ×400 (A, B, and D). Boxed regions are shown enlarged in B and D (enlarged ×9 and ×3, respectively). **P < 0.01, ***P < 0.001, Student’s t test.