TABLE 1.

SASP components identifiedin the regressing interdigits.

Genes	6 id	7.5 id	8 id
	Expression fold changes
Senescence-associated secretory phenotype (SASP; Lorda-Diez et al., 2015)
IL8L1	1.00 ± 0.04	11.10 ± 3.51*	20.59 ± 5.18*
IL8L2	1.02 ± 0.08	1.93 ± 0.22**	3.12 ± 0.46*
AREGB	1.05 ± 0.19	2.23 ± 0.43*	2.46 ± 0.71*
HGF	1.01 ± 0.08	1.98 ± 0.20**	1.85 ± 0.37*
TGFβ2	1.03 ± 0.07	1.85 ± 0.25*	2.53 ± 0.53*
IGF1	1.00 ± 0.01	5.72 ± 1.62*	7.86 ± 2.20*
IGFBP5	1.00 ± 0.02	7.70 ± 1.86**	19.36 ± 4.44**
MMP2	1.01 ± 0.06	2.79 ± 0.45**	4.47 ± 0.78*
MMP9	1.00 ± 0.02	2.49 ± 0.44**	4.33 ± 0.91*
Adamts9	1.00 ± 0.04	6.70 ± 1.11**	22.66 ± 5.92*
FAS	1.02 ± 0.04	1.88 ± 0.18***	1.81 ± 0.24*
TNFRSF21	1.00 ± 0.02	0.83 ± 0.12	1.62 ± 0.25*
TNFRSF23	1.03 ± 0.14	1.92 ± 0.31*	3.28 ± 0.88*
Other SASP components upregulated in the interdigit
TNFα	Wride et al., 1994
MMP11	Dupé et al., 1999
tTG	Dupé et al., 1999
FASLG	Svandova et al., 2017

The upper part of the table shows components undergoing intense transcriptional upregulation in the third interdigits of the chick limb. Note the increased expression from the stage preceding interdigit remodeling (id 6) to the stage of peak degeneration (id 8). The lower part of the table corresponds to characteristic SASP components reported to be expressed at high levels in the regressing interdigits of mouse and human embryos. ***p < 0.001; **p < 0.01; *p < 0.05 statistical significance (bold) in differences of gene expression levels between 7.5id (middle column) and 8id (right column) vs 6 id (left column).