CLDN5: From structure and regulation to roles in tumors and other diseases beyond CNS disorders

Claudin-5 (CLDN5) is an essential component of tight junctions (TJs) and is critical for the integrity of the blood-brain barrier (BBB), ensuring homeostasis and protection from damage to the central nervous system (CNS). Currently, many researchers have summarized the role and mechanisms of CLDN5 in CNS diseases. However, it is noteworthy that CLDN5 also plays a significant role in tumor growth and metastasis. In addition, abnormal CLDN5 expression is involved in the development of respiratory diseases, intestinal diseases, cardiac diseases, and diabetic ocular complications. This paper aims to review the structure, expression, and regulation of CLDN5, focusing on its role in tumors, including its expression and regulation, effects on malignant phenotypes, and clinical significance. Furthermore, this paper will provide an overview of the role and mechanisms of CLDN5 in respiratory diseases, intestinal diseases, cardiac diseases, and diabetic ocular complications.

Synephrine, as a scavenger and promoter, cooperates with hesperidin to reduce acrolein levels

Acrolein (ACR) is a harmful and active aldehyde produced in processed food that endangers foods safety. We undertook this work to explore the ACR-trapping ability of hesperidin (HES) and synephrine (SYN) from the diet. After comparing their ACR-trapping abilities, the reaction pathways of HES and SNY were analyzed using LC-MS/MS, and two adducts (HES-ACR-1 and SNY-2ACR) were synthesized, and their structures were identified by NMR. Then, we not only evaluated the synergistic trapping effects of HES and SNY on ACR in the model through the Chou-Talalay method but verified it in the processing of roasted duck wings and cookies. Furthermore, based on the quantitative analysis of the ACR-adducts of HES and SNY, we demonstrated that SYN, as a promoter, could greatly improve the ACR-capturing ability of HES by forming more adducts (3-fold). Our findings could serve as a guide for using SNY and HES as new scavengers in food processing.

Influence of ripeness and maceration of the grapes on levels of furan and carbonyl compounds in wine - Simultaneous quantitative determination and assessment of the exposure risk to these compounds

The validated method based on the use of headspace solid phase microextraction (HS-SPME) coupled with the comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometric detection (GC×GC/TOFMS) proved to be appropriate for this first simultaneous quantitative determination of six toxic compounds (formaldehyde, acetaldehyde, ethyl carbamate, furan, furfural and acrolein) found in wines. Acetaldehyde and acrolein coeluted with other wine compounds, which indicated that difficulties could arise if only one-dimensional gas chromatography was used for the determination of these compounds. The advancement of the ripeness degree and increasing the grape maceration time seems to result in higher concentrations of toxic compounds. The exposure to furan, acrolein and ethyl carbamate through wine consumption may pose risks to consumer health, since calculated MOE values were lower than 10,000.

Role of plant polyphenols in acrylamide formation and elimination

Acrylamide found in thermal-treated foods has led to an intensive and persistent research effort, since it is a neurotoxic, genotoxic and probable carcinogenic compound to humans. Plant polyphenols are the most abundant antioxidants in human diet. Several researches indicated that the polyphenols affected the acrylamide formation during heating. However, the controversial effects of the polyphenols on acrylamide formation were related to their structure, concentrations, and antioxidant capacity, as well as reaction condition. Polyphenols can inhibit acrylamide formation through trapping of carbonyl compounds and preventing against lipid oxidation, while some special polyphenols can enhance the acrylamide content by providing carbonyl groups, accelerating the conversion from 3-aminopropionamide (3-APA) to acrylamide and inhibiting acrylamide elimination. This review concludes the effects of polyphenols in the Maillard reaction and food systems conducted so far, aimed to give an overview on the role of plant polyphenols in acrylamide formation and elimination.

Acrolein relaxes mouse isolated tracheal smooth muscle via a TRPA1-dependent mechanism

Airway sensory C-fibres express TRPA1 channels which have recently been identified as a key chemosensory receptor for acrolein, a toxic and highly prevalent component of smoke. TRPA1 likely plays an intermediary role in eliciting a range of effects induced by acrolein including cough and neurogenic inflammation. Currently, it is not known whether acrolein-induced activation of TRPA1 produces other airway effects including relaxation of mouse airway smooth muscle. The aims of this study were to examine the effects of acrolein on airway smooth muscle tone in mouse isolated trachea, and to characterise the cellular and molecular mechanisms underpinning the effects of acrolein. Isometric tension recording studies were conducted on mouse isolated tracheal segments to characterise acrolein-induced relaxation responses. Release of the relaxant PGE₂ was measured by EIA to examine its role in the response. Use of selective antagonists/inhibitors permitted pharmacological characterisation of the molecular and cellular mechanisms underlying this relaxation response. Acrolein induced dose-dependent relaxation responses in mouse isolated tracheal segments. Importantly, these relaxation responses were significantly inhibited by the TRPA1 antagonists AP-18 and HC-030031, an NK₁ receptor antagonist RP-67580, and the EP₂ receptor antagonist PF-04418948, whilst completely abolished by the non-selective COX inhibitor indomethacin. Acrolein also caused rapid PGE₂ release which was suppressed by HC-030031. In summary, acrolein induced a novel bronchodilator response in mouse airways. Pharmacologic studies indicate that acrolein-induced relaxation likely involves interplay between TRPA1-expressing airway sensory C-fibres, NK₁ receptor-expressing epithelial cells, and EP₂-receptor expressing airway smooth muscle cells.