Table 2.

BBB function and junctional proteins in age related disorders, ischemic injury and immune system.

Experimental System	Claudin 5	Occludin	ZO-1	Permeability	Other	Authors
hypoxia, 8% O2, mouse, brain lysate	unaffected	decreased protein levels	unchanged protein levels	Na-fluorescein leakage increased	MMP and VEGF dependence	Bauer et al., 2010 [78]
		disrupted immunofluorescence for both
hypoxia in primary bovine brain microvessel endothelial culture		membrane localization perturbed	ZO2 membrane localization perturbed, ZO1 and ZO2 diffuse cytosolic staining	sucrose permeability increased	actin stress fibers, increased actin protein	Mark and Davis 2002 [79]
H2O2 ROS	unaffected	phosphorylation change, degradation			TEER increase	Lischper et al., 2010 [80]
+GM6001		rescues degradation			does not rescue
hypoxia/reoxygenation modeled by DMNQ treatment of primary mouse brain microvessel endothelial culture		protein decreased				Krizbai et al., 2005 [81]
hypoxia in bEND.3	altered localization, decreased protein			increased		Koto et al., 2007 [82]
reactive oxygen species	altered localization, decreased protein for both				xanthine oxidase and 100 μM hypoxanthine	Schreibelt et al., 2007. [83]
MCAO, 12 months vs. 2 months old mice	decrease in both age groups, after 3 days less protein in old compared to young		decrease in both age groups, after 1 and 3 days less protein in old	larger Evans blue extravasation in old with stroke		Shen et al., 2019 [84]
young adult rats hypoxia/reoxygenation		phosphorylation	no change in protein	increased		Witt et al., 2003 [85]
young adult rats hypoxia/reoxygenation		disrupted				Lochhead et al., 2010 [73]
as above + free radical scavenger tempol		rescued
young adult rats hypoxia/reoxygenation	disrupted localization, slightly increase membrane fraction	disrupted localization, slightly increase membrane fraction	disrupted localization	PKC-dependent focal BBB leakage		Willis et al., 2010 [86]
EGFP-Claudin 5 transgenic mouse tMCAO	eGFP-claudin 5 no change	no change	no change		Claudin 5 transgene protein expression is double of wild type.	Knowland et al., 2014 [87]
after 24–30 hours
after 48–58 hours	eGFP-claudin 5 non membrane	reduced	reduced
600–950 g rats compared to 200–250 g rats		degradation				Kaur et al., 2011 [88]
MCAO, both ages	slightly increased phosphorylation
tPA after reperfusion, only in old	greatly increased phosphorylation	increased degradation
rat tMCAO +PP2 Src kinase inhibitor, brain tissue	time dependent decrease of claudin 5 protein and mRNA was rescued by PP2			brain lysate protein decrease was significant from 24, mRNA from 72 hours and persisted 7 days later, fibrinogen leakage from brain coincided claudin 5 decrease and vas rescued by PP2		Bai et al., 2014, [89]
rat microsphere embolism, capillary lysate		decreased amount, increased phosphorylation 6–72 h after microsphere injection	decreased amount	albumin leakage starting from 48 hours		Kago et al., 2006 [90]
rat microsphere embolism, capillary lysate, +PP2		decreased amount and increased phosphorylation rescued by PP2		albumin leakage 6-24h, rescued by PP2		Takenaga et al., 2009 [91]
spontaneously hypertensive rats tMCAO, brain sections	rapid reorganization in localization 3 h after reperfusion + MMP2 activity at vessels. Protein appeared in astrocytes.			Increased gelatinase activity 3 h after reperfusion, rescued by MMP2 inhibition.		Yang et al., 2007, Yang and Rosenberg 2011 [92,93]
brain lysate	decreased mRNA, degraded protein rescued by BB-1101 MMP inhibitor
spontaneously hypertensive rats tMCAO+GM6001 MMP inhibitor	protein levels were rescued for all three					Yang et al., 2013 [94]
Primary human brain microvascular endothelial cells+PARP inhibition	increased protein levels for both					Rom et al., 2015 [95]
spontaneously hypertensive rats tMCAO + mynocicline	increased protein levels for all three					Yang et al., 2015 [96]
SRF, MRTF-A/-B knockdown hemorrhagic stroke model, whole brain tissue	claudin1, 3, 5 and 12 mRNA and claudin5 protein downregulated		ZO-2 and ZO-3 mRNA downregulated, ZO-1 unaffected			Weinl et al., 2015 [97]
bovine brain microvessel endothelial cells +VEGF		distribution changed from membrane to cytoplasm, protein levels increased		permeability increase, resistance decrease		Wang et al., 2001 [98]
adenoviral expression of IL-1 in VEGFA knockout mouse	VEGFA KO rescued protein expression of brain microvessels in inflammatory lesions for both					Argaw et al., 2012 [99]
EAE in VEGFA KO mouse	VEGFA KO rescued protein expression of brain microvessels in inflammatory lesions
VEGFR2 blocking antibodies in Cortical VEGF injected wild type mice	rescued protein expression for both
eNOS inhibition or silencing in human brain microvessel endothelial cells	rescued protein expression
24 months old mice compared to 3 months old, via fluorescence activated cell sorting	significantly decreased		decreased	IgG leakage	neurovascular inflammation and neuronal stress	Elahy et al., 2015 [100]
SAMP8 mice, 12 vs. 4 months old, permeability				no change in albumin permeability and insulin uptake		Banks et al., 2000 [101]