👤 Liudmyla I Stepanova

Light therapy, using red and near-infrared (NIR) irradiation, is currently applied for the treatment of various neurodegenerative diseases, such as Alzheimer's disease (AD). Transcranial photobiomodulation therapy (tPBMT) can alleviate neurodegeneration, neuronal loss, and β-amyloid peptide plaque burden. Alternatively, potential early inhibition of oxidative stress, neuroinflammation, apoptosis, and amyloidogenic cellular pathways may constrain pathological changes with aging. In this research, we conduct an 808-nm tPBMT with a 30-day course of daily 1-hour sessions for mice and assess its influence on molecular mechanisms related to the potential onset of neurodegeneration. To comprehensively identify molecular mechanisms of tPBMT on the brain cells, the next-generation whole RNA sequencing of over 30,000 mRNA of the cortex and hippocampus of BALB/c mice is performed. After tPBMT, transcriptional alterations are found in 1,005 genes in the hippocampus and 1,482 genes in the cortex. Pathway-gene enrichment network analysis identifies genes associated with about 20 pathways of neurodegeneration, and a disease-gene network is constructed. Particularly, tPBMT alters the transcription and expression of the essential genes associated with oxidative stress (NF-κBIα, JUN, JUND, and PKC genes), inflammation (DOCK4/6, IL-1RAPL1, and TNFαIP6), and apoptosis (CASP3, TNFαIP6, AKT3, CDKN1A, CYP51, RASA2, and RESTAT). Additionally, 808-nm light modulates the main risk genes for AD (BACE1, BACE2, PSEN2, APH1B, GATA2, YY2, RELA, STAT3, JUN, JUND, ARNTL, CREB3L1, CELF2, E2F4, ELK3, and CEBPD), involved in APP processing supporting AD development. Moreover, the APP concentration is reduced after tPBMT. Hence, PBMT may help inhibit the development of different neurodegeneration types and maintain normal brain conditions. Show less

Lipoprotein (a) [Lp(a)] is a highly heterogeneous lipoprotein particle promoting panvascular disease. Structurally, it consists of an LDL-like core covalently bound to apolipoprotein (a) [apo(a)]. Molecular determinants linking various genetic variants of apo(a) constituent of Lp(a) to vascular pathology remain incompletely defined. We have built a model allowing dissection which variations in LPA gene are functional, and which are mere associates of these functional variations. Copy number changes in kringle IV type 2 (KIV-2), together with a spectrum of single nucleotide polymorphisms (SNPs), regulate apo(a) size, expression, and function. These variants can be broadly categorized into Lp(a)-increasing, Lp(a)-lowering, and null alleles, with distinct prevalence across populations. Notably, risk alleles such as rs10455872 and rs3798220 account for substantial variance in circulating Lp(a) and confer elevated susceptibility to coronary artery disease, whereas splice-altering and nonsense alleles markedly reduce Lp(a) concentrations. The therapeutic implications of modifying circulating Lp(a) levels are profound. While conventional lipid-lowering therapies exert little influence on Lp(a), antisense oligonucleotides (pelacarsen) and small interfering RNA agents (olpasiran, SLN360) achieve robust Lp(a) reductions. Integrating genetic insights with structural modeling provides a framework to disentangle functional from proxy associations within LPA and neutralize the cardiovascular hazard conferred by elevated levels of Lp(a). Show less

In motile fibroblasts, stable microtubules (MTs) are oriented toward the leading edge of cells. How these polarized MT arrays are established and maintained, and the cellular processes they control, have been the subject of many investigations. Several MT "plus-end-tracking proteins," or +TIPs, have been proposed to regulate selective MT stabilization, including the CLASPs, a complex of CLIP-170, IQGAP1, activated Cdc42 or Rac1, a complex of APC, EB1, and mDia1, and the actin-MT crosslinking factor ACF7. By using mouse embryonic fibroblasts (MEFs) in a wound-healing assay, we show here that CLASP2 is required for the formation of a stable, polarized MT array but that CLIP-170 and an APC-EB1 interaction are not essential. Persistent motility is also hampered in CLASP2-deficient MEFs. We find that ACF7 regulates cortical CLASP localization in HeLa cells, indicating it acts upstream of CLASP2. Fluorescence-based approaches show that GFP-CLASP2 is immobilized in a bimodal manner in regions near cell edges. Our results suggest that the regional immobilization of CLASP2 allows MT stabilization and promotes directionally persistent motility in fibroblasts. Show less