Pathological changes and cognitive impairment caused by chronic cerebral hypoperfusion (CCH) have been previously reported. However, how these changes progress remains unclear. Additionally, there are few studies regarding the mechanism underlying the involvement of autophagy in these processes. Two-step bilateral common carotid artery occlusion (BCCAO) was performed to replicate CCH in Sprague Dawley rats. The animals were divided into seven groups, including a sham group and 2-, 4-, 8-, 12-, 16-, and 20-week BCCAO groups (n = 7 per group). Five additional rats were used to monitor cerebral blood fluid (CBF) changes via laser speckle contrast imaging (LSCI). We tested for cognitive changes and pathological changes, including neuronal injury, white matter lesions, and β-Amyloid (Aβ) deposition, via acknowledged methods. Autophagy was analyzed via western blotting and immunohistochemistry. Cognitive impairment appeared beginning at 8 weeks after BCCAO despite improvement in CBF. Neuronal damage began at 8 weeks in the hippocampal CA1 region and at 4 weeks in the cortex. White matter injury was detected in all BCCAO groups. Intracellular Aβ accumulation occurred earlier than extracellular plaque formation. The levels of autophagy-related proteins (Beclin-1, light chain 3B, and P62) increased beginning at 2 weeks in the cortex and at 4 weeks in the hippocampus and remained elevated throughout the remainder of the study period. Despite recovery of CBF, autophagy dysfunction occurred early after CCH and played an important role in neuronal deterioration, cognitive decline, and intracellular Aβ aggregation.

Chronic cerebral hypoperfusion (CCH) plays an insidious role in the development of cognitive impairment. Considerable evidence suggests that Diabetes Mellitus (DM) as a vascular risk factor may exacerbate CCH and is closely related to cognitive decline. Dysregulation of autophagy is known to be associated with the pathogenesis of neurodegenerative diseases such as Alzheimer’s disease. To elucidate the role of autophagy in CCH- and/or DM-related pathogenesis, mouse neuroblastoma Neuro-2a cells were exposed to hypoxia and/or high glucose for 48 h, mimicking CCH complicated with DM pathologies. Chronic hypoxia reduced cell proliferation and increased levels of cleaved caspase-3, whereas high glucose had no obvious synergistic toxic effect. Accumulation of autophagic vacuoles under hypoxia may be due to both autophagy impairment and induction, with the former accounting for Neuro-2a cell death. Additionally, aberrant accumulation of mitochondria in Neuro-2a cells may be attributed to insufficient BNIP3-mediated mitophagy due to poor interaction between BNIP3 and LC3-II. Despite the lack of a significant cytotoxic effect of high glucose under our experimental conditions, our data indicated for the first time that impaired autophagy degradation and inefficient BNIP3-mediated mitophagy may constitute mechanisms underlying neuronal cell damage during chronic hypoxia.

Neutrophil polarization is a basic activity involved in the innate immune response, and it may be initiated by extracellular Ca²⁺ entry, a process primarily mediated through store-operated Ca²⁺ entry (SOCE). Yet, the mechanisms by which SOCE participates in cell polarization remain unclear. We hypothesized that Akt- and Src-dependent pathways, traditionally linked to neutrophil polarization, may interact with SOCE in this event. In this study, SKF96365 and 2-APB, inhibitors of SOCE as proved by their inhibition on Mn²⁺ influx, were observed to inhibit the formyl-methionyl-leucyl-phenylalanine (fMLP)–induced influx of Ca²⁺, the activation of Akt, Src, Rac1, Rac2, and Cdc42, and the polarization of differentiated HL-60 (dHL-60) cells. Downregulation of stromal interaction molecule 1 (STIM1), a Ca²⁺ sensor identified to induce SOCE, by siRNA led to decreases in the following indexes: Ca²⁺ entry, activation of Akt, Src, Rac2 (rather than Rac1) and Cdc42, and fMLP-induced polarization. This study suggests that SOCE might be the predominant form of Ca²⁺ entry involved in the regulation of cell polarization, and it may act through the Akt/Src/Rac pathways, as modeled in dHL-60 cells. It also suggests that STIM1 is a key modulator of cell polarization, potentially serving as a target for the designation of anti-immune deficiency therapies.