Fig 2: CD44 expressed in the recipient’s tissue rather than on the infiltrating-cells enhances the development of T1D in the cell transfer model.A) CD44-deficient non-diabetic NOD male recipients were reconstituted with inflammatory spleen cells derived from WT (CD44+/+→CD44-/-; marked #1) or CD44-deficient (CD44-/-→CD44-/-; marked #2) diabetic NOD female donors. In addition, WT non-diabetic NOD male recipients were reconstituted with inflammatory spleen cells derived from WT (CD44+/+→CD44+/+; marked #3) or CD44-deficient (CD44-/-→CD44+/+; marked #4) diabetic NOD female donors. Inflammatory cells are marked by arrows and local islet cells by arrowhead. The pancreases of all 4 combinations were removed after detection of diabetes or 200 days after cell transfer. Doing so, pancreases that were harvested approximately at the same time, were stained with anti-CD44 mAb. B) The % of diabetes-free mice (exhibiting less than 250 mg/dL urine glucose) was determined in corresponding four mouse groups, described in A. Statistical analysis by Breslow: #2 versus #3, P < 0.01; #1 versus #2 (follow up 75 to 200 days), P < 0.03; #3 versus #4 (follow up 20 to 75 days), P < 0.03.

Fig 3: Marker expression in passage 2 (P2) cultured cSM-MSCs. A Evaluation of CD markers by flow cytometry in P2 cultured normal (circle) and OA (square) cSM-MSCs. Expression is shown as the percentage (%) of positive cells (events) of all live cells for CD90, CD44, CD73, CD271, CD34, and CD45. RT-qPCR analysis of B CD marker expression, C chondrogenic lineage and D osteogenic lineage markers in P2 cultured cSM-MSCs. Gene expression of the markers is shown on a log scale as the relative gene expression compared to the mean of all samples within a gene. Each dot represents an individual donor

Fig 4: CD44 involvement in T1D.Three CD44-dependent pathways affect the fate of T1D in NOD mice. I. CD44 involvement in inflammatory cell migration (blue). Inflammation upregulates CD44 on the islet-infiltrating cells. The firm adhesion of the CD44 receptor to the HA substrate slows the motility of the inflammatory cells on the endothelium. II. CD44 involvement in peripheral insulin sensitivity and glucose uptake (green). CD44 expression on peripheral tissue, increases insulin sensitivity and glucose uptake by, for example, muscle and liver cells, resulting in reduced hyperglycemia. Compensation for insulin-deficiency (see pathway III) may explain this event. III. CD44 involvement in β cell apoptotic death (red). Inflammation-induced cytokines up-regulate CD44 expression on β cells. CD44 expression on β cells is associated with increased β cell dysfunction and susceptibility to apoptosis, which could be triggered by the binding of HA fragments to CD44 receptor. However, large HA fragments could interfere with the detrimental effect of LMW-HA on β cells. The β cell dysfunction and susceptibility to apoptosis is indicated by increased iNOS induction and subsequent NO production, increased caspase-3 activity (Western blot, not shown), reduced glucose-stimulated insulin secretion, and reduced insulin content. As an outcome of β cell demise, hyperglycemia is detected, implying the development of T1D. Broken arrows and question marks represent pathways and factors that are yet to be established.

Fig 5: Graphical overview of the CD marker expression in the synovial membrane. A Synovial membrane (SM) was collected from normal and OA knee joints B Immunohistochemical staining was performed for CD90, CD44, CD73, and CD271. Tissue expression of these markers is visualized in red. Immunopositivity of CD90 was observed mainly in the subintimal and perivascular layer. CD44 was mainly expressed in the intimal lining cells, although variable expression was observed in the subintimal layer and perivascular. CD73 positive cells were mostly observed in the intimal lining and perivascular layer. CD271 was expressed perivascular and in the normal SM also in the intimal layer of the adipose parts of the synovial membrane