Anti-CD9 Monoclonal antibody, clone LND9 [FITC]

Exosomes from bone marrow stem cells or cardiac progenitor cells can reduce apoptosis in myocardial cells after ischemia and reperfusion injury. However, there is little known about the effects of exosomes from adipose-derived stem cells (ADSCs), which are more abundant and have a lower risk of side effects. The aim of this study was to characterize exosomes from ADSCs and evaluate their cardioprotective actions against ischemia reperfusion injury. The exosomes were isolated from ADSCs and analyzed by protein marker expression, transmission electron microscopy, and nanoparticle tracking analysis. The ADSC-exosomes were then used for ex vivo investigation of the cardioprotective effects on cardiomyocytes after exposure to oxidative stress. Exosomes from ADSCs exhibited a diameter of 150 nm and expressed the marker proteins, CD9 and CD29. ADSC-exosomes had no effect on proliferation of untreated cardiomyocytes. In contrast, ADSC-derived exosomes reduced apoptosis in myocardial cells subjected to oxidative stress. This study confirms that exosomes originating from ADSCs can protect cardiomyocytes from oxidative stress.

The cluster of differentiation 81 (CD81), a member of the transmembrane 4 superfamily, is primarily found to be expressed in a wide variety of cells including T and B cells of vertebrates as a critical modulator. In the present study, the open reading frame of a CD81 gene homolog (Lja-CD81) was cloned in lamprey, Lampetra japonica, which is 702 bp long and encodes a protein of 233-amino acids. Although Lja-CD81 seems to be close to CD9 molecules in their full-length sequences, Lja-CD81 possesses higher identity to vertebrates' CD81 than to CD9 (including a lamprey CD9) molecules in their large extracellular loops. In addition, it also possesses a myristoylation site (Met-Gly-Val-Glu-Gly-Cys-Leu-Lys) in its N-terminal region which is identical to the N-terminal regions of CD81 molecules. These data suggest that CD9 and CD81 molecules diverged no later than the emergence of jawless vertebrates. The mRNA levels of Lja-CD81 in lymphocytes and supraneural myeloid bodies were up-regulated significantly after stimulation with mixed anti-gens, and a similar expressional pattern of Lja-CD81 at protein level was also confirmed. Furthermore, Lja-CD81 was found to be co-localized with variable lymphocyte receptor B (VLRB) evenly on the cell membrane of peripheral blood lymphocytes isolated from control group, but they were found to aggregate on one side of the membrane of peripheral blood VLRB+ lymphocytes after stimulation with mixed antigens. All these results indicate that the Lja-CD81 identified in lamprey may play an important role in the immune response of lamprey VLRB+ lymphocytes.