Table 1 Annotation of the 14 most significant features used in discriminating stimulated vs. unstimulated MSCs.

1

123.0552

3.2E + 00

4.4E − 03

Niacinamide

C₆H₆N₂O

[M + H]⁺

123.0553

0

MS/MS matched with database

2

137.0465

1.5E − 01

2.1E − 02

Hypoxanthine

C₅H₄N₄O

[M + H]⁺

137.0458

4

MS/MS matched with database

3

146.0598

2.2E + 01

1.8E − 05

3-Methyldioxyindole

C₉H₉NO₂

[M + H-H₂O]⁺

146.0600

1

IM-MS/MS main fragments matched with in silico fragments.^b

4

163.9777

2.4E + 00

5.4E − 03

Taurine

C₂H₇NO₃S

[M + K]⁺

163.9778

1

Potassium adduct of taurine chemical standard could not be fragmented; accurate mass matched with standard

5

170.0321

2.3E + 00

2.0E − 02

Creatine

C₄H₉N₃O₂

[M + K]⁺

170.0326

3

MS/MS matched with database

6

209.0927

1.6E + 01

7.6E − 04

l-Kynurenine

C₁₀H₁₂N₂O₃

[M + H]⁺

209.0921

3

MS/MS matched with chemical standard MS/MS

7

220.1077

3.9E + 02

2.5E − 15

5-Hydroxy-l-tryptophan

C₁₁H₁₂N₂O₃

[M + NH₄-H₂O]⁺

220.1080

1

MS/MS manually matched

8

227.0793

6.6E − 03

4.6E − 14

l-Tryptophan

C₁₁H₁₂N₂O₂

[M + Na]⁺

227.0791

1

MS/MS matched with chemical standard MS/MS

9

232.0762

2.6E + 01

1.0E − 05

Cysteinyl-Glutamine

C₈H₁₅N₃O₄S

[M + H-H₂O]⁺

232.0756

2

N/A

10

243.0745

2.1E + 02

2.9E − 10

5-Hydroxy-l-tryptophan

C₁₁H₁₂N₂O₃

[M + Na]⁺

243.0740

2

MS/MS matched with chemical standard MS/MS

11

247.0476

2.6E + 02

1.5E − 09

l-Kynurenine

C₁₀H₁₂N₂O₃

[M + K]⁺

247.0479

1

MS/MS partially matched with L-Kynurenine standard MS/MS

12

265.1559

2.2E + 00

1.8E − 02

5-Tetradecenoic acid (or other isomers)

C₁₄H₂₆O₂

[M + K]⁺

265.1564

2

N/A

13

377.3017

4.2E + 00

2.1E − 02

2/3-hydroxydodecanoyl carnitine

C₁₉H₃₇NO₅

[M + NH₄]⁺

377.3010

2

N/A

14

785.5781

1.8E − 01

3.7E − 03

PC (35:4)

C₄₃H₇₈NO₈P

[M + NH₄]⁺

785.5803

2

MS/MS matched with database