The Versatility of Collagen in Pharmacology: Targeting Collagen, Targeting with Collagen.

Collagen, a versatile family of proteins with 28 members and 44 genes, is pivotal in maintaining tissue integrity and function. It plays a crucial role in physiological processes like wound healing, hemostasis, and pathological conditions such as fibrosis and cancer. Collagen is a target in these processes. Direct methods for collagen modulation include enzymatic breakdown and molecular binding approaches. For instance, Clostridium histolyticum collagenase is effective in treating localized fibrosis. Polypeptides like collagen-binding domains offer promising avenues for tumor-specific immunotherapy and drug delivery. Indirect targeting of collagen involves regulating cellular processes essential for its synthesis and maturation, such as translation regulation and microRNA activity. Enzymes involved in collagen modification, such as prolyl-hydroxylases or lysyl-oxidases, are also indirect therapeutic targets. From another perspective, collagen is also a natural source of drugs. Enzymatic degradation of collagen generates bioactive fragments known as matrikines and matricryptins, which exhibit diverse pharmacological activities. Overall, collagen-derived peptides present significant therapeutic potential beyond tissue repair, offering various strategies for treating fibrosis, cancer, and genetic disorders. Continued research into specific collagen targeting and the application of collagen and its derivatives may lead to the development of novel treatments for a range of pathological conditions.

Usnea aurantiaco-atra (Jacq) Bory: Metabolites and Biological Activities.

BACKGROUND: Lichens are complex symbiotic associations between a fungus and an alga or cyanobacterium. Due to their great adaptability to the environment, they have managed to colonize many terrestrial habitats, presenting a worldwide distribution from the poles to the tropical regions and from the plains to the highest mountains. In the flora of the Antarctic region, lichens stand out due to their variety and development and are a potential source of new bioactive compounds. METHODS: A phytochemical study of the Antarctic lichen Usnea aurantiaco-atra (Jacq) Bory was conducted with the intention of determining the most important metabolites. In addition, the cytotoxic and antioxidant activities of its extracts were determined. RESULTS: Cytotoxicity studies revealed that the hexane extract contains usnic acid as a majority metabolite, in addition to linoleic acid, ergosterols and terpenes, and demonstrates cytotoxic activity against an A375 melanoma cell line. On the other hand, the presence of total phenols in the extracts did not influence their antioxidant activity. CONCLUSIONS: U. aurantiaco-atra contains mainly usnic acid, although there are terpenes and ergosta compounds that could be responsible for its cytotoxic activity. The presence of phenols did not confer antioxidant properties.

SP1 and NFY Regulate the Expression of PNPT1, a Gene Encoding a Mitochondrial Protein Involved in Cancer.

The Polyribonucleotide nucleotidyltransferase 1 gene (PNPT1) encodes polynucleotide phosphorylase (PNPase), a 3'-5' exoribonuclease involved in mitochondrial RNA degradation and surveillance and RNA import into the mitochondrion. Here, we have characterized the PNPT1 promoter by in silico analysis, luciferase reporter assays, electrophoretic mobility shift assays (EMSA), chromatin immunoprecipitation (ChIP), siRNA-based mRNA silencing and RT-qPCR. We show that the Specificity protein 1 (SP1) transcription factor and Nuclear transcription factor Y (NFY) bind the PNPT1 promoter, and have a relevant role regulating the promoter activity, PNPT1 expression, and mitochondrial activity. We also found in Kaplan-Meier survival curves that a high expression of either PNPase, SP1 or NFY subunit A (NFYA) is associated with a poor prognosis in liver cancer. In summary, our results show the relevance of SP1 and NFY in PNPT1 expression, and point to SP1/NFY and PNPase as possible targets in anti-cancer therapy.

Expression of the human TIMM23 and TIMM23B genes is regulated by the GABP transcription factor.

The TIM23 protein is a key component of the mitochondrial import machinery in yeast and mammals. TIM23 is the channel-forming subunit of the translocase of the inner mitochondrial membrane (TIM23) complex, which mediates preprotein translocation across the mitochondrial inner membrane. In this paper, we aimed to characterize the promoter region of the highly similar human TIM23 orthologs: TIMM23 and TIMM23B. Bioinformatic analysis revealed putative sites for the GA-binding protein (GABP) and the recombination signal binding protein for immunoglobulin kappa J (RBPJ) transcription factors in both promoters. Luciferase reporter assays, electrophoretic mobility shift assays, and chromatin immunoprecipitation experiments showed three functional sites for GABP and one functional site for RBPJ in both promoters. Moreover, silencing of GABPA, the gene encoding the DNA-binding subunit of the GABP transcription factor, resulted in reduced expression of TIMM23 and TIMM23B. Our results show an essential role of GABP in activating TIMM23 expression. More broadly, they suggest that physiological signals involved in activating mitochondrial biogenesis and oxidative function also enhance the transcription but not the protein level of TIMM23, which is essential for maintaining mitochondrial function and homeostasis.

NRF-1 is the major transcription factor regulating the expression of the human TOMM34 gene.

The human TOMM34 gene encodes a cytosolic protein with chaperone-like activity that helps import some preproteins to the mitochondria by keeping them in an unfolded, import-compatible state. TOMM34 was found to be upregulated frequently in colorectal tumors, suggesting that it also has a role in the growth of cancer cells. In this context, TOMM34 is a potential target for novel anticancer drugs, and it might also be used in the diagnosis of colorectal cancer. Nuclear respiratory factors (NRFs) play an important role in governing the nuclear-mitochondrial interactions implicated in mitochondrial biogenesis. Our previous studies revealed that NRFs promote the expression of the major members of the mitochondrial transport machinery, TOMM70 and TOMM20. Here we report the existence of binding sites for NRF-1, Sp1, and NRF-2 in the 5' region of the human TOMM34 gene. We determined the effects of mutations at these sites on promoter activity in HeLa S3 and A204 cells, in conjunction with chromatin immunoprecipitation experiments, electrophoretic mobility shift assays, and in vivo methylation analysis of the promoter region. We conclude that NRF-1 is the main transcription factor regulating the expression of TOMM34. Sp1 interacts with NRF-1 to stimulate the promoter's full activity.

NRF-2 transcription factor is required for human TOMM20 gene expression.

TOMM20 is a subunit of the outer mitochondrial membrane translocase that plays a major role as a receptor of precursor proteins with N-terminal cleavable presequences targeted to the mitochondria. Nuclear respiratory factors 1 and 2 (NRF-1 and NRF-2) play an important role in governing nucleo-mitochondrial interactions implicated in mitochondrial biogenesis. It was recently reported that NRF-2 is critical for maintaining normal transcriptional levels of the TOMM20 gene, but the promoter of this gene is uncharacterized. We report the presence of a NRF-2 and two NRF-1 binding motifs in the 5'-flanking region of the human TOMM20 gene and provide insight into their roles for promoter activity by using chromatin immunoprecipitation experiments and reporter assays in HeLa S3 and A204 cells. We show that only NRF-2 and the proximal NRF-1 motifs are involved in the expression of the gene. The NRF-2 binding site is required to activate transcription. The proximal NRF-1 site cooperates with NRF-2 in regulating the expression of the gene. The distal NRF-1 binding site is not functional.