Experimental design.

<p>The diagram captures time course of temperature, introduction of stem cells, evaluation of cell viability and mitochondrial activity under different treatment conditions.</p

Measurement of cell viability and mitochondrial activity in PRNCs.

<p>Moderate hypothermia treatment indicated significant increase cell viability compared to normothermic and sever hypothermia treatments, and enhanced stem cells’ neuroprotection. Black- and white-columns indicate non-implementation and MSCs implementation after 2 hours reperfusion, respectively. Control shows a normoxic condition, atmosphere at 37°C, 95% O₂, and 5% CO₂. + Under same temperature condition, <i>P</i> value of comparison non-MSCs with MSCs implementation is less than 0.05. *<i>P</i><0.05: **<i>P</i><0.01: ***<i>P</i><0.005. Similarly, moderate hypothermia treatment indicated significant increase in mitochondrial activity compared to normothermic and severe hypothermia treatments, and enhanced stem cells’ neuroprotection. Black- and white-columns indicate non-implementation and MSCs implementation after 2 hours reperfusion, respectively. Cont shows a normoxic condition, atmosphere at 37°C, 95% O₂, and 5% CO₂. + Under same temperature condition, <i>P</i> value of comparison non-MSCs with MSCs implementation is less than 0.05. *<i>P</i><0.05: **<i>P</i><0.01: ***<i>P</i><0.005. a.u. = absorbance unit.</p

Non-opioid neuroprotective mechanisms accompanying combination therapy of moderate hypothermia, MSCs and DADLE.

<p>Results revealed significant upregulation of GDNF, but not NGF or BDNF after combination therapy with or without DADLE (OGD-Treated) compared to OGD-Untreated and Control (Panel A). GDNF was also upregulated slightly in OGD-Untreated condition, likely due to an endogenous compensatory mechanism of the PRNCs. Similarly, OGD-Treated significantly reduced apoptosis compared to Control and OGD-Untreated. Apoptosis via ApoAlert assay is quantified (Panel B) and representative images shown (Panel C) (a-c are Hoechst-stained PRNCs, whereas d-f are corresponding apoptotic stained cells; a/d: Control; b/e: OGD-Treated; c/f: OGD-Untreated). There were no significant differences in cell cycle condition across the three conditions (Panel D). Symbols represent **p<0.0005 vs. Control GDNF; *p<0.0005 vs. Control GDNF; §§p<0.0001 vs. OGD-Treated GDNF (Panel A); **p<0.0001 vs. control; *p<0.005 vs. control and untreated (Panel B). Dashed lines in Panels A, B and D (pink, red, and black, respectively) indicate combined treatment of moderate hypothermia and MSCs without DADLE. Solid lines in Panels A, B and D (pink, red, and black, respectively) indicate treatment with antibody against GDNF and combined treatment of moderate hypothermia and MSCs without DADLE.</p

TBI accelerated extracellular Aβ deposits in the hippocampus of AD-TBI mice.

<p>Statistical analysis revealed a significant upregulation of extracellular Aβ deposits in the AD mice that received TBI compared to the NT mice that received TBI and the AD and NT mice that received sham surgery (Panel A). MAP2 staining revealed a significant decrease of MAP2 positive cells in the hippocampus of AD mice that received TBI compared to the AD and NT mice that received sham surgery (Panel B). Immunofluorescence for the detection of extracellular Aβ deposits and MAP2 (Panel C). Scale bars = 50 µm. The insets correspond to representative high magnifications of MAP2 images. Scale bars  = 100 µm. The brain illustration shows the location of the brain slices chosen for histological analysis. * p < 0.05, ** p < 0.01, *** p < 0.001, **** p < 0.0001.</p

Prior to TBI surgery (A), the number of errors on trial 1 (T1), trial 4 (T4), and the 30 minute retention trial (T5) for NT (yellow) and AD (blue) mice during the final two days of RAWM testing.

<p>Asterisk indicates significant improvement from T1 for that group at p<0.05 or higher level of significance. For Post-TBI testing, the number of errors on T1, T4, T5 for the RAWM at two weeks (<b>B</b>) and six weeks (<b>C</b>) after TBI. NT-Sham (hatched yellow, n = 9), NT-TBI (solid yellow, n = 10), AD-Sham (hatched blue, n = 8), and AD-TBI (solid blue, n = 7) mice. Single asterisk indicates the AD-TBI group is significantly different from all other groups at p<0.02. Double asterisk indicates the AD-TBI group is significantly different from AD-Sham at p<0.01. The error bars represent the SEM.</p

Experimental design is shown.

<p>For cohort 1, animals were trained in the RAWM prior to TBI surgery and then tested for cognitive deficits in the RAWM at two and six weeks post-TBI. For cohort 2, there was no pre-TBI behavioral training or post-TBI behavioral testing. All the animals were euthanized at six weeks post-TBI and the brains were harvested for histological analysis.</p

DPC co-culture protects rat neural cells against OGD.

<p>Co-culture of rat primary neural cells with DPCs afforded neuroprotection against OGD dose-dependently in both Trypan blue and MTT activity assays of cell viability (a–f). The percentages correspond to the ratio of DPCs co-cultured with rat primary neural cells as follows: 1∶1 (100%), 1∶2 (50%), 1∶4 (25%), and 1∶0 (0%). DPCs co-cultured with rat primary neural cells under non-OGD condition did not alter cell viability in both assays (g–l). Asterisk* corresponds to statistically significant difference (p<0.05 vs. 0%). a,g: 0%; b,h: 25%; c,i: 50%; d,j: 100%; e,k: Trypan blue stain quantification; f,l: MTT assay quantification.</p

Stem Cell Recruitment of Newly Formed Host Cells via a Successful Seduction? Filling the Gap between Neurogenic Niche and Injured Brain Site

<div><p>Here, we report that a unique mechanism of action exerted by stem cells in the repair of the traumatically injured brain involves their ability to harness a biobridge between neurogenic niche and injured brain site. This biobridge, visualized immunohistochemically and laser captured, corresponded to an area between the neurogenic subventricular zone and the injured cortex. That the biobridge expressed high levels of extracellular matrix metalloproteinases characterized initially by a stream of transplanted stem cells, but subsequently contained only few to non-detectable grafts and overgrown by newly formed host cells, implicates a novel property of stem cells. The transplanted stem cells manifest themselves as pathways for trafficking the migration of host neurogenic cells, but once this biobridge is formed between the neurogenic site and the injured brain site, the grafted cells disappear and relinquish their task to the host neurogenic cells. Our findings reveal that long-distance migration of host cells from the neurogenic niche to the injured brain site can be achieved through transplanted stem cells serving as biobridges for initiation of endogenous repair mechanisms. This is the first report of a stem cell-paved “biobridge”. Indeed, to date the two major schools of discipline in stem cell repair mechanism primarily support the concept of “cell replacement” and bystander effects of “trophic factor secretion”. The present novel observations of a stem cell seducing a host cell to engage in brain repair advances basic science concepts on stem cell biology and extracellular matrix, as well as provokes translational research on propagating this stem cell-paved biobridge beyond cell replacement and trophic factor secretion for the treatment of traumatic brain injury and other neurological disorders. </p> </div

Hsp-27-mediated neuroprotection following DPC transplantation in stroke.

<p>Hsp27 appears to be targeted by DPCs for neuroprotection in stroke. Following intracerebral transplantation, DPCs survived in the stroke brain and elevate Hsp27 expression which may afford rescue of the ischemic penumbra proximal, as well as distal from the transplant site. Although the transplanted cells do not migrate far from the transplant site, the anti-oxidative stress protein Hsp27 is able to amplify the neuroprotection.</p

Laser-captured biobridge, corresponding to the brain tissue between SVZ and impacted cortex, expressed high levels of MMP-9 gelatinolytic activities at one month and three months post-TBI in animals transplanted with SB623 which were significantly higher than those TBI animals that received vehicle only or sham-operated animals (*p’s< 0.05 vs. vehicle or sham; Panel A).

<p>Although vehicle-infused TBI animals also showed a significantly upregulated MMP-9 gelatinolytic activity at one month post-TBI (**p< 0.05 vs. sham), the level of this neurovascular proteinase activity reverted back to control-sham levels at three months post-TBI. Each bar represents the mean ± standard deviation from n=3 per treatment group for each time point. Next, to further reveal that SB623 cells promoted cell migration via an ECM-mediated mechanism, primary rat cortical cells were either grown alone or co-cultured with SB623 in the presence or absence of the MMP-9 inhibitor Cyclosporine-A (Panel <b>B</b>). Migratory cell assay (see inset) revealed significantly enhanced migration of primary rat cortical cells into the chamber that contained SB623, which was significantly suppressed by treatment with the inhibitor (*p< 0.05 vs. all other treatment conditions). The absence of SB623 and inhibitor in the cell culture condition, the treatment of the inhibitor alone, and the combined treatment of SB623 and inhibitor did not significantly differ in the resulting cell migratory potential.</p