Table 1.
Process to define which integrins repress CNTF
| Integrin | FG | TSP | COL | LAM | VTN | FN1 | Leukocyte | Antibody |
|---|---|---|---|---|---|---|---|---|
| α1β1 |
|
|
i, ii, iii |
i, ii, iii |
|
|
|
β1 |
| α2β1 |
|
i, iii |
i, ii, iii |
i, ii, iii |
|
ii |
|
β1 |
| α3β1 |
|
i, ii, iii |
|
i, iii |
|
ii |
|
β1 |
| α4β1 |
|
i, iii |
|
|
|
i, ii, iii |
X |
β1 |
| α4β7 |
|
|
|
|
|
i, ii, iii |
X |
|
| α5β1 |
ii |
iii |
|
|
|
i, ii, iii |
|
β1 |
| α6β1 |
|
iii |
|
i, ii, iii |
|
|
|
α6, β1 |
| α6β4 |
|
|
|
i, ii, iii |
|
|
|
β6 |
| α7β1 |
|
|
|
i, ii, iii |
|
|
|
β1 |
| α8β1 |
|
|
|
|
|
i, ii, iii |
|
β1 |
| α9β1 |
|
|
|
|
|
|
X |
β1 |
| α10β1 |
|
|
i, iii |
|
|
|
|
β1 |
| α11β1 |
|
|
i, ii, iii |
|
|
|
|
β1 |
| αvβ1 |
|
|
|
|
ii |
i, ii, iii |
|
β1 |
| αvβ3 |
i, ii, iii |
i, ii, iii |
|
ii |
i, ii, iii |
i, ii, iii |
|
|
| αvβ5 |
|
|
|
|
i, ii, iii |
ii |
|
αv, β5 |
| αvβ6 |
|
|
|
|
|
i, ii, iii |
|
αv |
| αvβ8 |
|
|
|
|
|
ii |
|
αv |
| αdβ2 |
|
|
|
|
iii |
iii |
X |
|
| αLβ2 |
|
|
|
|
|
|
X |
|
| αmβ2 |
i, ii, iii |
|
|
|
|
|
X |
|
| αxβ2 |
i, ii, iii |
|
iii |
|
|
|
X |
|
| αEβ7 |
|
|
|
|
|
|
X |
|
| αIIbβ3 | i, ii, iii | i, ii, iii | i, ii, iii | i, ii, iii |
We applied the following process to help us to decide which subunit blocking antibodies to test and which integrins most likely repress CNTF. When “italics” appears in a row, that specific integrin is considered unlikely to be involved in repressing CNTF. We first used the data from the ECM substrate experiment (Figure 1A) and the known integrin binding partners to eliminate potential integrins involved in repressing CNTF. Thus, fibrinogen (FG), thrombospondin (TSP), and collagen (COL) had no significant effect on CNTF mRNA levels in C6 cells, as indicated by “italics” in the row of their known integrin partners. The numbers in the cells indicate the following articles that list the specific ligand – integrin relationship: i) Humphries et al., [34] ii) Plow et al. [38], and iii) Takada et al., [39]. Laminin (LAM), vitronectin (VTN), and fibronectin (FN) significantly reduced CNTF expression, as indicated by “bold” numbers in the respective columns. Next, to further help with antibody selection, we eliminated all leukocyte-specific integrins [21]) as they are not present on glial cells (second to last column). Lastly, the results from the antibody experiment (Figure 1B) were used to eliminate a number of β1- and α6-containing integrins (“italics” letters in the last column), leaving three candidates which potentially repress CNTF (“bold” letters in the last column).