Table 1.
Summarized alterations in fatty acyl chain length and saturation in unbound and protein-bound epidermal lipids in Fatp4−/− mice.
| Fraction number | Lipid class | Acyl chain lengtha | Changes in Fatp4−/− | ||||
|---|---|---|---|---|---|---|---|
| Saturated | Unsaturated | ||||||
| ≥C25 | <C25 | ≥C25 | <C25 | ||||
| Unbound FAs | 4 & 5 | NHFA | C14-C34 | ≅ | ↑e | ↑ | ↑e |
| AHFA | C18-C26 | ? | ↑ | n.a. | varied | ||
| BHFA | C26 | ? | n.a. | n.a. | n.a. | ||
| OHFA | C30-C36 | ↓ | n.a. | ↑e | n.a. | ||
| OAHFA | C30-C36 | ↓ | n.a. | ↑e | n.a. | ||
| Unbound lipids | 3 | Cer(NS) | C16-C32 | ↓ | ↑ | ↑e | ↑e |
| Cer(NdS) | C24-C26 | ↓ | ↓ | n.a. | n.a. | ||
| Cer(NP) | C22-C26 | ≅ | ↑ | n.a. | n.a. | ||
| Cer(AS) | C16-C28 | ? | ↑d | ↑ | ↑ | ||
| Cer(AdS) | C16, C27, C28 | n.a. | ≅ | ? | n.a. | ||
| Cer(BS) | C26 | ↓c | n.a. | n.a. | n.a. | ||
| Cer(OS) | C32-C36 | ↓ | n.a. | ↑e | n.a. | ||
| Cer(EOS) | C30-C36 | ↓ | n.a. | ↓ | n.a. | ||
| 6 | GlcCer(NS) | C16-C28 | ↓ | ≅ | ↑ | ≅ | |
| GlcCer(NdS) | C24-C26 | ↓ | ↓ | n.a. | n.a. | ||
| GlcCer(NP) | C22-C26 | ↓ | ≅ | n.a. | n.a. | ||
| GlcCer(AS) | C16-C28 | ? | ↑d | ↑ | ↑ | ||
| GlcCer(AdS) | C16, C27, C28 | n.a. | ↓ | ? | n.a. | ||
| GlcCer(BS) | C26 | ? | n.a. | n.a. | n.a. | ||
| GlcCer(OS) | C32-C36 | ↓ | n.a. | ↓e | n.a. | ||
| GlcCer(EOS) | C30-C36 | ↓ | n.a. | ↓ | n.a. | ||
| 2 | 1-O-Cer(ENS) |
C16-C28; C16-C26b |
↓ | ↑e | ↑e | ↑ | |
| 3 | MAG | C22-C30 | ↓ | ↓ | n.a. | n.a. | |
| Protein-bound FAs | 4 & 5 | OHFA | C32-C36 | n.a | n.a | ↓ | n.a |
| Protein-bound lipids | 3 | Cer(OS) | C28-C36 | ↓ | n.a. | varied | n.a. |
Fractionated unbound and protein-bound epidermal lipids of newborn mice were analyzed by ESI-MS and quantified as described in Materials and Methods. Changes in lipid abundance in Fatp4−/− mice compared to controls were summarized in 4 categories based on the chain length (≥C25 or <C25) and saturation (saturated or unsaturated) of the fatty acyl chains. 1-O-Cer(ENS) species that carry two saturated acyl chains are categorized as saturated whereas those that carry one or two unsaturated acyl chains are categorized as unsaturated. aamide-linked acyl chain or acyl backbone; b1-O-linked acyl chain; cassessed by TLC; dnot for C16; enot for all species; ↑ and ↓, abundance significantly increased or decreased, respectively, compared to controls; ≅, abundance unchanged compared to controls; ?, abundance unknown; n.a., non-applicable.