Loss of <i>fatp</i> induces adult-onset progressive degeneration of PRs.

<p>(A–G) Consequences of <i>fatp</i> knockdown by RNA interference on PR viability. (A, B, C) Visualization of PRs using a cornea-neutralization method for 1-, 15- and 21-day-old PRs expressing <i>lacZ</i> as a control. (D, E, F) PRs expressing the <i>fatp</i>-interfering RNA and (G) PR quantification. Whereas all PRs were present in control retina and <i>fatp</i>-knocked-down retina at day one (A, D), there were significant PR losses at days 15 and 21 in <i>fatp</i>-knocked-down retina (B vs E, C vs F, t-test, n≥6). (H) Time-course analysis of <i>fatp^k10307</i> mutant mosaic retina using the Tomato/GFP-FLP/FRT method and (I) quantification. All outer PRs (R1–R6) expressed GFP (green). FLP-mediated mitotic mutant clones were visualized by the absence of rh1-tdTomato (red). Clones of the same eye were visualized in the same fly at day one, four, eight and fourteen after hatching. (H) All PRs were present at day one (scale bar = 10 µm). (H′) From day four, mutant PRs (in green) started to disappear. (H″ and H′″) Losses of mutant PRs were significant at day eight and day fourteen (paired t-test, n = 3). (I) Quantified results are expressed as mean ± SD. (J) Analysis of a control 15-day-old mosaic retina using the Tomato/GFP-FLP/FRT method. All PRs are present. (K–N) Rescue of <i>fatp^k10307</i>-mutant PRs by re-expression of wild-type <i>fatp</i>. (K) Tomato/GFP-FLP/FRT visualization of 10- to 14-day-old control, (L) <i>fatp^{k10307/k10307}</i> and (M) <i>fatp^{k10307/k10307}+rh1>fatp</i> mosaic retinas and (N) quantification (t-test, n> = 5). In the control (K), all PRs were present. In <i>fatp</i> mutant mosaic retina (L), 70% of the mutant PRs were lost. In these retinas, mutant PRs were rescued by re-expression of <i>fatp</i> under the control of the <i>rh1</i> promoter (M).</p

<i>fatp</i> is expressed in the adult retina.

<p>(A) Western blot analysis of en-GAL4 UAS-GFP (en>GFP) and en-GAL4 UAS-fatp (en>fatp) adult eye extracts using anti-Fatp C11-7 and anti-tubulin antibodies. Anti-Fatp C11-7 detects a single band at 72 kDa, which corresponds to the predicted molecular weight of Fatp. Endogenous and ectopically expressed Fatp were detected. Tubulin was used as a loading control. (B, C) Immunofluorescent detection of Fatp in wild-type (CS) and GMR-GAL4 UAS-fatp (GMR>fatp) third instar larva eye imaginal disc using the anti-Fatp C11-7 antibody (scale bar = 200 µm). (C) Fatp was detected in the posterior part of the disc, which corresponds to the expression profile of the GMR promoter. (D–E) Immunostaining of endogenous Fatp and Actin in whole-mount <i>cnbw</i> adult retina using the anti-Fatp C11-7 antibody and phalloidin. In the tangential (D) and longitudinal plans (E), Fatp immunostaining is detected in the cytoplasm of PRs (star) and accessory cells (arrowhead). Rhabdomeres are stained with phalloidin (scale bar = 20 µm).</p

<i>Rh1^G69D</i> rescues PR viability in the <i>fatp</i> mutant.

<p>(A–E) Analysis of the survival of control, <i>fatp^k10307</i>, <i>rh1^G69D/+</i> and <i>fatp^k10307rh1^G69D/+</i> double mutant PRs using the Tomato/GFP-FLP/FRT method in 15-day-old flies (scale bar = 10 µm). (E) Quantification of mutant PR losses (t-test, n≥12). PR loss in the <i>fatp^k10307 rh1^G69D/+</i> double mutant was dramatically lower than in the <i>fatp</i> single mutant. (F–J) Analysis of the survival of control, <i>fatp^k10307</i>, <i>rh1^G69D/+</i> and <i>fatp^k10307 rh1^G69D/+</i> double mutant PRs using resin-embedded tangential sections in 28-day-old flies (scale bar = 10 µm). (J) Quantification of PR loss. Significantly more PRs died in the <i>fatp</i> mutant than in control retina (t-test, n = 6). In the double mutant, PR losses were reduced to control levels. (K–N) Electron microscopy analysis of whole-eye control (K), <i>fatp^k10307</i> (L), <i>rh1^G69D/+</i> (M) and <i>fatp^k10307 rh1^G69D/+</i> (N) mutants in 28-day-old flies (scale bar = 1 µm). Whereas PRs degenerated in <i>fatp^k10307</i> ommatidia (arrow) and were phagocytosed by IOCs (*), PRs survived in <i>fatp^k10307 rh1^G69D/+</i> double mutant flies. Rhabdomeres of <i>rh1^G69D/+</i> and <i>fatp^k10307 rh1^G69D/+</i> outer PRs were reduced in size. Arrowheads show artifactual shadows on the sample.</p

The visual response is altered in <i>fatp</i> mutant PRs.

<p>(A–F) Tomato/GFP-FLP/FRT visualization of <i>fatp^k10307</i> mutant mosaic retinas from 5- and 8-day-old flies reared from the pupal stage in normal room light (350 lux) or in darkness (0 lux) (scale bar = 10 µm). (G) Quantification of <i>fatp^k10307</i> mutant PR loss. (A, D) No PR losses occurred in control mosaic retinas from 5-day-old and 8-day-old flies reared in room light conditions. (B, E, G) In <i>fatp</i> mutant retinas from light-reared flies, 58.8±4.5% and 68.5±4.9% of the mutant PRs were lost in 5-day-old and 8-day-old flies, respectively. (C, F, G) PR losses were significantly lower in flies reared in the dark (t-test, n = 8). (H) ERG recordings from control and <i>fatp^{k10307/k10307}</i> 8-day-old retinas and (I) quantification. Retinas were exposed to a one second flash of orange light. (I) The amplitude of the plateau is significantly higher in the <i>fatp</i> mutant retina than in the control retina (t-test, n = 24).</p

Elevated Rh1 levels are responsible for PR loss in the <i>fatp</i> mutant.

<p>(A) Western blot analysis of Rh1 in boiled head extracts from control, <i>fatp^{k10307/k10307}</i>, <i>rh1^G69D/+</i> and <i>fatp^{k10307/k10307}</i>/<i>rh1^G69D/+</i> 1 to 11-day-old flies. Tubulin was used as a loading control. (B) Quantification of protein levels. Dimer and oligomer forms of Rh1 were due to the boiling of the extracts. Rh1 levels were twofold higher in the <i>fatp</i> mutant than in the control. The level of Rh1 was substantially lower in the <i>rh1^G69D/+</i> single mutant and in the <i>fatp^{k10307/k10307}</i>/<i>rh1^G69D/+</i> double mutant. (C) Western blot analysis of Rh1 and tubulin in <i>fatp</i> mutant mosaic retina extracts from 5-day-old flies reared from the embryonic stage on control (+VitA) and vitamin A-deficient (-VitA) media. Tubulin was used as a loading control. Rh1 was not detectable in flies reared on vitamin A-deficient medium. (D, E) Visualization of <i>fatp</i> mutant mosaic retina of 5-day-old flies reared from the embryonic stage on control (D) and vitamin A-deficient (E) media using the Tomato/GFP-FLP/FRT method (scale bar = 10 µm). (F) Quantification of mutant PR loss (t-test, n≥12). <i>fatp</i> mutant PR viability was dramatically restored in flies reared on vitamin A-deficient medium. (G–J) Analysis of the loss of <i>fatp^k10307</i>, <i>fatp^k10307 arr2^3/+</i> and <i>fatp^k10307 arr2^3/3</i> double mutant PRs using resin-embedded tangential sections in 34-day-old flies (scale bar = 10 µm). (H) Quantification of PR loss. In the double mutants retinas, PRs were significantly rescued (p = 0.0021 and p = 0.0016, t-test, n = 6).</p

Histological analysis of <i>fatp^−/−</i> PR degeneration.

<p>(A–E) Analysis of <i>fatp^k10307</i> mutant PR survival using resin-embedded tangential sections. (A, C) Control retina of 1- and 35-day-old flies (scale bar = 10 µm). (B, D) Homozygous <i>fatp^k10307</i> retina of 1-day-old and 35-day-old flies. (E) PR losses in <i>fatp</i> mutant retinas were significant at 35 days compared to those in control retinas (t-test, n = 6). (F–M) Electron microscopy analysis of <i>fatp^−/−</i> PR degeneration. <i>fatp^k10307</i> mosaic retina of 15-day-old flies were analyzed. (F) Wild-type and heterozygous clones were marked with numerous large pigment granules in the IOCs and at the basis of PR rhabdomeres (white spots, above the black line) whereas homozygous mutant part exhibited rare small pigment granules (under the black line, scale bar = 10 µm). Several PRs were missing in the homozygous mutant part. (G–M) Different stages of <i>fatp^{k10307/k10307}</i> PR degeneration (scale bar = 1 µm). (G) <i>fatp^{k10307/k10307}</i> PR exhibiting no sign of degeneration. (H) The cytoplasm of <i>fatp^{k10307/k10307}</i> PRs shrank and became electron-dense (arrow). Some mitochondria were swelling (arrowhead). The rhabdomere was not much affected (*). (I–J) PRs then disintegrated. This was clearly visible at the level of the rhabdomere (*). (K, L, M) Degenerating PRs were finally phagocytosed and digested by the neighboring interommatidial cell (yellow).</p

Switching Invariant Natural Killer T (iNKT) Cell Response from Anticancerous to Anti-Inflammatory Effect: Molecular Bases

Since the discovery in 1995 of α-galactosylceramide <b>1</b> (α-GalCer), also known as KRN7000, hundreds of compounds have been synthesized in order to activate invariant natural killer T (iNKT) cells. Such keen interest for this lymphocyte cell type is due to its ability to produce different cytokines that bias the immune response toward a Th1 or Th2 profile. Thus, an understanding of the immune polarization mechanism via iNKT activation may pave the way toward new therapeutics in various domains including cancer and infectious and autoimmune diseases. In this review, we propose an up-to-date analysis of iNKT activators associated with a structure–activity relationship (SAR) study aimed at complementing available reviews by highlighting molecular bases for a selective immune response

Effect of CS exposure on colonic pro-inflammatory and anti-inflammatory cytokine expression induced by DSS.

<p>Cytokine expression in colon homogenates was determined by real time qPCR analysis and normalized by the β-actin expression. Graph represents the mean of the fold expression of each cytokine with the expression level measured to control animals (no CS exposure, no DSS) used as a reference and set to one. Data are pooled from two independent experiments with a total of 17–20 mice/group; error bars represent SEM. NS, Non significant; Number on the graph represents p value.</p

CS exposure did not modulate the development of colitis induced by DSS in CD1d^−/− mice.

<p>A. Mice body weight changes during induction of colitis. Body weight changes were calculated by dividing body weight on the specified day by the body weight of the starting day (day 0) and expressed in percent (3</p

Effect of CS exposure on NKT cell recruitment.

<p>A. Percentage of iNKT cells (TCRβ⁺ CD1d tetramer⁺) in CD45⁺ cells in the colonic mucosa of mice exposed or not to CS. Colonic tissues of several mice per group (3 to 5 animals) were pooled before cell extraction in order to obtain enough cell for cytometry analysis. On the left: a representative dot plot is shown. Numbers indicate iNKT cell percentage. On the right: Graph represents the mean value ± SEM of the iNKT cell percentage in the colonic mucosa according to CS exposure (n = 32 mice/condition from 3 independent experiments). Number on the graph represents p value. B. Vα14 mRNA expression in the colon as determined by real time qPCR analysis after normalization by the β-actin expression (17</p