Synergistic effect of cerium chloride and calcium chloride alters calcium signaling in keratinocytes to promote epidermal differentiation.

Epidermal keratinocytes undergo morphological and functional changes during differentiation, eventually being enucleated to become corneocytes. Calcium has been shown to be involved in various cellular functions of epidermal cells, including proliferation, differentiation, and apoptosis. Cerium is a lanthanide-series element and rare earth metal. For skin, cerium oxide has been investigated for use in absorbing UV and promoting wound healing. However, the functions and physiological effects of inorganic cerium on the skin have rarely been investigated. Here, we focused on cerium's function in epidermal keratinocytes and its interaction with calcium by investigating their effects on cell differentiation and intracellular calcium concentration. This study showed that applying cerium chloride to epidermal keratinocytes altered calcium signaling. It also suggested that cerium and calcium induced an increase in intracellular calcium concentration and promoted keratinocyte differentiation.

Ionic composition of Shotokuseki extract alters cell differentiation and lipid metabolism in three-dimensional cultured human epidermis.

Corneocytes and intercellular lipids form the stratum corneum. The content and composition of intercellular lipids in the stratum corneum significantly affect skin barrier function. The purpose of this study was to demonstrate the effect of Shotokuseki extract (SE) on intercellular lipid production and metabolism in human three-dimensional cultured human epidermis. SE or ion mixtures containing five common ions were applied to three-dimensional cultured human epidermis for 2-8 days for each assay. The mRNA expression levels of epidermal differentiation markers and lipid metabolism genes were quantified by real-time PCR. After extraction of lipids from the epidermis, ceramide, sphingosine, free fatty acids, and cholesterol were quantified by LC-MS/MS, GC-MS, or HPLC. The results showed that the application of SE increased the gene expression levels of epidermal differentiation markers keratin10 and transglutaminase. Elongation of very long-chain fatty acids protein 3, serine palmitoyl transferase, ceramide synthase 3, and acid ceramidase mRNA expression levels increased and fatty acid synthase mRNA expression decreased. The content of each lipid, [EOS] ceramide decreased and total sphingosine content increased on day 4. On day 8 of application, ceramide [NDS], [NP], and [EODS] increased and total free fatty acid content decreased. These results show that SE alters the lipid composition of the epidermis, increasing ceramides and decreasing free fatty acids in the epidermis. The composition of the ions in the SE may be responsible for the changes in lipid composition. These behaviors were different from those observed when the ion mixture was applied. Supplementary Information: The online version contains supplementary material available at 10.1007/s10616-024-00616-3.

Vacuolar-ATPase-mediated muscle acidification caused muscular mechanical nociceptive hypersensitivity after chronic stress in rats, which involved extracellular matrix proteoglycan and ASIC3.

Although widespread pain, such as fibromyalgia, is considered to have a central cause, peripheral input is important. We used a rat repeated cold stress (RCS) model with many characteristics common to fibromyalgia and studied the possible involvement of decreased muscle pH in muscle mechanical hyperalgesia. After a 5-day RCS, the muscle pH and the muscular mechanical withdrawal threshold (MMWT) decreased significantly. Subcutaneously injected specific inhibitor of vacuolar ATPase (V-ATPase), bafilomycin A1, reversed both changes almost completely. It also reversed the increased mechanical response of muscle thin-fibre afferents after RCS. These results show that V-ATPase activation caused muscle pH drop, which led to mechanical hypersensitivity after RCS. Since extracellular matrix proteoglycan and acid sensitive ion channels (TRPV1 and ASIC3) have been considered as possible mechanisms for sensitizing/activating nociceptors by protons, we investigated their involvement. Manipulating the extracellular matrix proteoglycan with chondroitin sulfate and chondroitinase ABC reversed the MMWT decrease after RCS, supporting the involvement of the extracellular mechanism. Inhibiting ASIC3, but not TRPV1, reversed the decreased MMWT after RCS, and ASIC3 mRNA and protein in the dorsal root ganglia were upregulated, indicating ASIC3 involvement. These findings suggest that extracellular mechanism and ASIC3 play essential roles in proton-induced mechanical hyperalgesia after RCS.

The ion balance of Shotokuseki extract promotes filaggrin fragmentation and increases amino acid production and pyrrolidone carboxylic acid content in three-dimensional cultured human epidermis.

Natural moisturizing factor (NMF) in the stratum corneum contributes to the retention of moisture there. The purpose of this study was to determine the penetration of ions in Shotokuseki extract (SE) into the three-dimensional cultured epidermis and the effect of NMF on the biosynthesis of amino acids and pyrrolidone carboxylic acid formation. Various ions, amino acids and pyrrolidone carboxylic acid were quantified by inductively coupled plasma mass spectrometry, fully automatic amino acid analyzer or high-performance liquid chromatography (HPLC) in three-dimensional cultured epidermis after application of SE. Gene expression levels of profilaggrin, calpain1, caspase14, and bleomycin hydrolase, which are involved in NMF production, were determined by reverse-transcription qPCR and bleomycin hydrolase activity was determined by aminopeptidase assay. The application of SE increased Na, K, Mg, Ca, Al, and Fe levels in three-dimensional cultured epidermis. The mRNA levels of the starting material of amino acid synthesis profilaggrin, and calpain1 and bleomycin hydrolase, which are involved in its fragmentation, increased. The activity of bleomycin hydrolase also increased. Furthermore, the levels of amino acids and pyrrolidone carboxylic acid increased in the three-dimensional cultured epidermis. This suggests that the ionic composition of SE may be involved in its moisturizing effect on the stratum corneum.

Synthesis and properties of rhodium(III) porphyrin cyclic tetramer and cofacial dimer.

Rhodium(III) porphyrin complexes, [Rh(4-PyT(3)P)Cl](4) (1) and [Rh(2-PytB(3)P)Cl](2) (2) (4-PyT(3)P = 5-(4-pyridyl)-10,15,20-tritolylporphyrinato dianion, 2-PytB(3)P = 5-(2-pyridyl)-10,15,20-tri(4-tert-butyl)phenylporphyrinato dianion), were self-assembled and characterized by (1)H nuclear magnetic resonance spectroscopy, infrared spectroscopy, and electron spray ionization-mass spectroscopy methods. The spectroscopic results certified that the rhodium porphyrin complexes 1 and 2 have a cyclic tetrameric structure and a cofacial dimeric structure, respectively. The X-ray structure analysis of 1 confirmed the cyclic structure of the complex. The Soret bands of both oligomers were significantly broadened by excitonic interactions between the porphyrin units, compared to those observed for a corresponding analogue of Rh(TTP)(Py)Cl (TTP = 5,10,15,20-tetratolylporphyrinato dianion, Py = pyridine). Stepwise oxidation of the porphyrin rings in the oligomers was observed by cyclic voltammetry. The oligomers 1 and 2 are very stable in solution, and they slowly undergo reactions with pyridine to give corresponding monomer complexes only at high temperatures (approximately 80 degrees C).