The blood–brain barrier (BBB) is a highly specialized neurovascular unit that protects the brain from potentially harmful substances. In addition, the BBB also engages in the exchange of essential nutrients between the vasculature and brain parenchyma, which is critical for brain homeostasis. Brain diseases, including neurological disorders and cerebrovascular diseases, are often associated with disrupted BBB integrity, evidenced by increased permeability. Therefore, defining the mechanisms underlying the regulation of BBB integrity is crucial for the development of novel therapeutics targeting brain diseases. MicroRNAs (miRNA), a type of small non-coding RNAs, are emerging as an important regulator of BBB integrity. Here we review recent developments related to the role of miRNAs in regulating BBB integrity.

Background: HCC is a leading cause of cancer-related death. The role of reactive oxygen species (ROS) in HCC remains elusive. Since a primary ROS source is the mitochondrial electron transport chain complex Ι and the NADH:ubiquinone Oxidoreductase Subunit B3 (NDUFB3), a complex I subunit, is critical for complex I assembly and regulates the associated ROS production, we hypothesize that some HCCs progress by hijacking NDUFB3 to maintain ROS homeostasis. Methods: NDUFB3 in human HCC lines was either knocked down or overexpressed. The cells were then analyzed in vitro for proliferation, migration, invasiveness, colony formation, complex I activity, ROS production, oxygen consumption, apoptosis, and cell cycle. In addition, the in vivo growth of the cells was evaluated in nude mice. Moreover, the role of ROS in the NDUFB3-mediated changes in the HCC lines was determined using cellular and mitochondrion-targeted ROS scavengers. Results: HCC tissues showed reduced NDUFB3 protein expression compared to adjacent healthy tissues. In addition, NDUFB3 knockdown promoted, while its overexpression suppressed, HCC cells’ growth, migration, and invasiveness. Moreover, NDUFB3 knockdown significantly decreased, whereas its overexpression increased complex I activity. Further studies revealed that NDUFB3 overexpression elevated mitochondrial ROS production, causing cell apoptosis, as manifested by the enhanced expressions of proapoptotic molecules and the suppressed expression of the antiapoptotic molecule B cell lymphoma 2. Finally, our data demonstrated that the apoptosis was due to the activation of the c-Jun N-terminal kinase (JNK) signaling pathway and cell cycle arrest at G0/G1 phase. Conclusions: Because ROS plays essential roles in many biological processes, such as aging and cancers, our findings suggest that NDFUB3 can be targeted for treating HCC and other human diseases.

Hepatocellular carcinoma (HCC) remains one of the most aggressive and lethal malignancies worldwide, with high rates of metastasis and recurrence contributing to its poor prognosis. There is an urgent need to elucidate the molecular mechanisms driving HCC progression and to develop effective therapeutic strategies. Metabolic reprogramming, especially aerobic glycolysis known as the Warburg effect, is a well-established hallmark of cancer. Concurrently, cancer stem cells (CSCs) play crucial roles in tumor initiation, therapy resistance, and recurrence. However, the involvement of long non-coding RNAs (lncRNAs) in linking metabolic alterations and stemness remains poorly understood. In this investigation, we identified LINC02041 as a significantly upregulated lncRNA in HCC tissues and demonstrated its oncogenic role in promoting cell proliferation. We found that STAT3 transcriptionally activates LINC02041 expression. Mechanistically, LINC02041 enhances the stability of SRSF1 protein by suppressing its ubiquitin-mediated degradation, thereby facilitating HCC cell proliferation, migration, glycolytic metabolism, and acquisition of stem-like properties. Our findings delineate a novel STAT3/LINC02041/SRSF1 regulatory axis that coordinately modulates glycolytic reprogramming and stemness maintenance in hepatocarcinogenesis. This study not only advances our understanding of HCC pathophysiology but also identifies LINC02041 as a promising prognostic biomarker and a compelling therapeutic target for novel therapeutic strategies against this aggressive malignancy.