The quest for effective anti-aging treatments has driven scientific and medical research, particularly pharmacological approaches. In the aging model organism Caenorhabditis elegans, various long-lived mutants have been used for longevity signaling research (Rahimi et al., 2022; Stein et al., 2022); however, there are still unsolved mechanisms for shared target proteins that influence cellular longevity. Here, we present collagen proteins as commonly elevated biomarkers with the potential to help understand the organismal aging process. The extracellular matrix (ECM), of which collagen is the main component, provides an environment for the body and, in addition to its well-recognized role as a structural support, influences many important cellular processes within the body (Rahmati et al., 2017). As a result, age-related changes in ECM proteins have far-reaching consequences, with the potential to disrupt many aspects of homeostasis and health.

As major components of the ECM, collagen proteins have significant potential as therapeutic targets for anti-aging interventions. This study aimed to contribute to the development of innovative anti-aging treatments by harnessing the regenerative capabilities of essential collagen proteins. By investigating the role of collagen proteins in the lifespan and health span of C. elegans, we aimed to identify specific collagen protein types and elucidate their roles in longevity and skin aging. Additionally, we discuss emerging therapeutic strategies aimed at enhancing collagen production or function to mitigate the signs of aging and improve skin health. The insights gained from this research could pave the way for novel interventions that not only address age-related concerns, but also promote overall skin resilience and vitality.

Data collection and processing

We collected transcriptomic data on C. elegans from the National Center for Biotechnology Information (NCBI) Gene Expression Omnibus, focusing on samples of long-lived mutants from the GSE37303, GSE93724, GSE106672, GSM3580882, and GSM5434782 datasets. Data processing was performed using the ggplot2 package v. 3.5.1 (https://ggplot2.tidyverse.org) and ggVennDiagram packages in R (ver. 4.4.1) (https://cran.r-project.org/web/packages/ggVennDiagram/index.html).

C. elegans maintenance and worm synchronization

C. elegans strains were maintained on nematode growth medium (NGM) agar plates at 20°C using Escherichia coli OP50 bacteria as the food source. The Bristol N2 wild-type strain was obtained from the Caenorhabditis Genetics Center (Minneapolis, MN, USA). To obtain synchronized nematodes, six unmated hermaphrodites were placed on an NGM plate with sufficient food. After 4 days, lysed F1 progenies that were selfing hermaphrodites yielded synchronized hermaphrodite eggs. The eggs were then grown on NGM plates. E. coli OP50 was cultured at 37°C in LB medium for up to 12 h. The bacterial concentration was calculated by counting the number of colonies and measuring the OD at a wavelength of 600 nm. E. coli OP50 was centrifuged, resuspended, and diluted in H2O to a concentration of 10×10¹¹ bacteria mL^-1.

Collagen preparation

We used DNA encoding full-length (aa 1-2944) recombinant hCOL7A1, the chain region (17-2,944 aa), the non-helical region (17-1,253 aa), and the triple-helical region (1,254-2,784 aa). These DNA fragments were amplified using Pfu DNA polymerase. The amplified DNAs were inserted into pcDNA3.1-HA or pET-28a vectors. Recombinant proteins were overexpressed in E. coli BL21 (DE3). The bacterial cells were lysed by sonication three times (10 s duration at 50 s intervals). His-tagged proteins were purified from the supernatants using 1 mL of Ni-NTA resin (GE Healthcare, Chicago, IL, USA). Filtered supernatants were incubated with the resin for 1 h at 4°C under continuous rotation. After washing the resin with washing buffer (phosphate-buffered saline [PBS], pH 7.4; 0, 10, 50, and 100 mM imidazole), the proteins were eluted with elution buffer (PBS, 500 mM imidazole, pH 7.4). Eluted proteins were dialyzed at 4°C overnight against PBS (pH 7.4) in dialysis tubing cellulose membranes (Sigma-Aldrich, St. Louis, MO, USA). Eluted proteins were stored at −80°C until use.

Liquid chromatography (LC)-mass spectrometry (MS) and tandem MS (MS/MS) data analysis

Ultra-high performance LC-MS analysis of the trypsin digestion products was performed using a TripleTOF 5600+ instrument (ABSCIEX, Framingham, MA, USA) coupled with a 1290 Infinity II system (Agilent, Santa Clara, CA, USA). Acquisition was performed on a quadrupole time-of-flight mass spectrometer over a full scan range of m/z 50-3,000. The resulting data were searched against COL7A1 protein (bonding collagen T7) using BPVflex software (ABSCIEX) and PeakView^® software (ABSCIEX). For the BPVflex search, the total intensity threshold was set at 0.05% of the intensity of the base chromatogram peak.

Lifespan analysis

Lifespan assays were carried out at 20°C on liquid culture plates using standard protocols and were replicated in three independent experiments. C. elegans individuals were synchronized with 70 μL of M9 buffer, 25 μL of bleach (10% sodium hypochlorite solution) and 5 μL of 10 N NaOH. After either a timed 64 h of egg laying or egg preparation, approximately 150 young adults were transferred to fresh S-medium (S-basal medium supplemented with 3 mM CaCl₂, 3 mM MgSO₄, 50 lM EDTA, 25 lM FeSO₄, 10 lM MnCl₂, 10 lM ZnSO₄, 1 lM CuSO₄, and 10 mM KH₂PO₄ [pH 6.0]) with E. coli OP50. Collagen peptide solutions were added to the medium at various concentrations. Living worms were then transferred to assay plates. Worms that crawled through the plates or exhibited internal progeny hatching were excluded, and those that showed no reaction to gentle stimulation were scored as dead. Lifespan data were analyzed using R software (ver. 4.1.0, “coin” package ver 1.4.3) (https://cran.r-project.org/web/packages/coin); Kaplan-Meier survival curves were depicted, and p values were calculated using the log-rank (Mantel-Cox) test.

C. elegans movement and body-bending assay

On day 10, 10-15, worms were transferred to fresh NGM plates and recorded for 30 s using a microscope (Olympus SZ61 microscope with Olympus camera eXcope T300; Olympus, Tokyo, Japan). Subsequently, five independent movement clips per experimental condition were analyzed using TSView 7 software (ver. 7.1) (Olympus, Tokyo, Japan), and the average speed was calculated as the distance traveled (mm) per second. The body-bending frequency of 30 worms per condition was assessed for 20 s using an SZ61 microscope (Olympus). Body-bend counts were recorded using an Olympus eXcope T300 camera at an 18-fold optical zoom. The videos were played back at a speed of 0.5× and counted. A count was recorded each time the back of the nematode pharynx reached its maximum bend in the opposite direction of the previous count.

Progeny assay

For the fertility assay, worms were synchronized, and a single L4 nematode was transferred onto a single plate by applying vehicle or collagen solutions, and then transferred to fresh plates. The progeny of the worms were allowed to hatch and were counted.

Stress resistance assays

Synchronized worms were treated under each condition for 10 days. For the oxidative stress assay, 30 worms were placed on solid NGM plates containing 0.4M paraquat (PESTANAL; Sigma-Aldrich) for 3 h. The assays were repeated nine times, and the paraquat plates were freshly prepared on the day of the assay. For the thermotolerance assay, 30 worms were exposed to 35°C for 16 h and surviving worms were counted. Assays were performed in triplicate, and the survival rate was estimated.

Superoxide dismutase and catalase activity assays

To assess antioxidant enzyme activity, 10-day-old worms were ground in liquid nitrogen. Superoxide dismutase (SOD) and catalase activity levels were measured using an SOD colorimetric activity kit (Invitrogen, Carlsbad, CA, USA) and a catalase activity colorimetric/fluorometric assay kit (Biovision, Milpitas, CA, USA), respectively. Worm pellet samples were assessed in triplicate according to the manufacturer’s protocol. SOD and catalase activities were determined using standard curves, followed by normalization to protein concentrations using a bicinchoninic acid (BCA) protein assay (Pierce, Rockford, IL, USA).

Lipofuscin (age pigment) analysis

Nematodes were synchronized and treated for 10 days with vehicle or collagen solutions from the L4 larval stage (day 0). To measure lipofuscin accumulation, day 10 worms were washed three times with M9 buffer and distributed in a 96-well plate (Porvair Sciences, Norfolk, UK; black with glass-bottomed imaging plates, #324002). Lipofuscin autofluorescence was determined using a fluorescence plate reader (Synergy H1, Agilent Technology, Winooski, VT, USA; excitation: 390-410, emission: 460-480) and normalized to the stable signal of the worms (excitation: 280-300, emission: 320-340) as a blank.

Triglyceride (TG) quantification

TG content was measured using a triglyceride colorimetric assay kit (Abcam, Waltham, MA, USA) according to the manufacturer’s protocol. Briefly, worm pellets were frozen in liquid nitrogen containing 5% Triton X-100. The pellets were sonicated and diluted for protein determination using a BCA assay (Pierce). The samples were heated to 80°C and shaken for 5 min, then cooled to room temperature to solubilize the TGs. TG content was normalized to protein content, and three independently collected worm pellets were assayed for each experimental condition.

Cell culture

Primary human dermal fibroblasts (HDFs; American Type Culture Collection, Manassas, VA, USA) and immortalized HaCaT cells (Addexbio, San Diego, CA, USA) were maintained in Dulbecco’s modified Eagle’s medium (DMEM; Lonza, Slough, UK) containing 4.5 g/L glucose and supplemented with 2 mM L-glutamine, 100 IU/mL penicillin, 100 μg/mL streptomycin, and 10% (v/v) fetal bovine serum (FBS) (Sigma-Aldrich). The cells were cultivated in T-flasks at 37°C in a humidified atmosphere containing 5% CO₂.

Measurement of collagen biosynthesis

HaCaT cells were seeded in 12-well plates (1×10⁵ cells per well) and grown in DMEM containing 5% FBS for 24 h. The medium was then replaced with fresh assay medium containing 0.1% FBS, and the corresponding treatment was tested for collagen production. After 48 h of incubation, the cell culture medium was collected and centrifuged at 3,000 rpm for 15 min. The levels of collagen I secreted from treated cells were quantified using an enzyme-linked immunosorbent assay kit (Takara Bio Inc., Otsu, Japan) according to the manufacturer’s instructions. Measurements were repeated at least three times with an independent cohort of cells.

RNA sequencing (RNA-seq), data analysis, and visualization

HFDs were seeded into six-well plates (3×10⁵ cells per well) and grown in DMEM containing 5% FBS for 24 h. Next, the medium was replaced with fresh assay medium containing 0.1% FBS. After 48 h of incubation, the cell culture medium was completely removed and stored at −80°C. RNA was extracted and assayed using a Bioanalyzer 2100 (Agilent Technologies, Waltham, MA, USA) in combination with an RNA 6000 Nano kit. Matched samples with high RNA integrity scores were subjected to sequencing. For library preparation, 2 mg of total RNA per sample was processed using a TruSeq RNA Sample Prep Kit (Illumina, San Diego, CA, USA) following the manufacturer’s instructions. The quality and quantity of the libraries were determined using an Agilent Bioanalyzer 2100 in combination with FastQC v0.11.7, and sequencing was performed on a HiSeq4000 in the SR/50 bp/high output mode at the Macrogen Bioinformatics Center (Macrogen, Seoul, Korea). The libraries were multiplexed at five units per lane. Sequencing resulted in 35 Mio reads per sample. Sequence data were extracted in FastQ format using bcl2fastq v1.8.4 and used for mapping. FASTQ output files were aligned to WBcel235 C. elegans genome using STAR (Senchuk et al., 2018). These files were deposited in the Sequence Read Archive (SRA) under accession number PRJNA1143071. The average mapping of sequence reads to the reference genome was 75%. Transcripts were filtered using the Trimmomatic 0.38 platform (Bolger et al., 2014). Differential expression analysis was performed using HISAT2 version 2.1.0, Bowtie2 2.3.4.1, and StringTie version 2.1.3b (Pertea et al., 2015, 2016). Gene lists were evaluated for functional classification and statistical overrepresentation using the Database for Annotation, Visualization, and Integrated Discovery (DAVID) version 6.8 and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway database.

Statistical analysis

All experiments were repeated at least three times, with identical or similar results. Data represent biological replicates. Statistical analysis was performed for each assay. The data satisfied the hypotheses of the statistical tests described in each experiment. Data are expressed as the mean ± standard deviation in all figures unless stated otherwise. R software (ver. 4.1.1) (https://www.r-project.org) was used for statistical analyses. A p-value <0.05 was considered significant.

Data availability

Source data for all figures and tables used in this study. Experimental data supporting the plots within this paper and other findings of this study are available from the corresponding author upon reasonable request. The RNA-seq data generated in the present study have been deposited in NCBI’s SRA and are accessible through the submission number PRJNA1143071. The source data are provided in this study.

Identification of collagen as a target mediator of longevity

In this study, we aimed to identify common genetic mediators of C. elegans long-lived mutants by hypothesizing specific gene alterations regardless of the various longevity signaling pathways. The general research process is presented in Fig. 1A. We utilized transcriptome data for long-lived mutants obtained from the NCBI Gene Expression Omnibus (GEO; GSE37303, GSE93724, GSE106672, GSM3580882, and GSM5434782) as input data. Among the various long-lived mutants, we used transcriptomic data from nine mutant strains and one long-lived condition: dietary restriction (DR). First, we categorized the RNA-seq data into three groups: DR-mimic, antioxidative, and genetic longevity. In the DR-mimicking state, we sorted the genes commonly showing increased expression levels for DR conditions, abnormal pharyngeal pumping mutant eat-2(ad1116), and abnormal dauer formation mutant daf-2(e1370) strains. Using Venn diagram analysis, 433 genes were filtered and grouped into 58 collagen genes, 11 antioxidative genes, and 6 heat-shock protein genes (Fig. 1B, Supplementary Table 1). For the antioxidative state, the iron-sulfur protein mutant isp-1(qm150), superoxide dismutase-2 mutant sod-2(ok1030), and NADH ubiquinone oxidoreductase mutant nuo-1(ua1) were analyzed. Among 138 genes commonly showing increased expression levels, 30 collagen-cuticle genes, 12 lifespan-related genes, and 15 protein enzyme genes were categorized and listed (Fig. 1C, Supplementary Table 1). Moreover, in the genetic-longevity state group, 16 genes, including five collagen genes and three glutathione genes were sorted according to four mutant strains, namely, slow biological timing mutant clk-1(qm30), abnormal germ line proliferation mutant glp-1(e2141), initiation factor 4E (eukaryotic translation initiation factor 4E, EIF4E) strain ife-2(ok306), and osmotic avoidance abnormal strain osm-5(p813) (Fig. 1D, Supplementary Table 1). Collectively, C. elegans collagen-cuticle genes were closely associated with lifespan extension in three types with 10 long-lived conditions (Fig. 1, Supplementary Table 1).

Figure 1. Identification of commonly altered genes in long-lived conditions of nematodes. (A) Study flow diagram. (B) Venn diagram analysis of dietary restriction (DR) and eat-2(ad1116) and daf-2(e1370) mutants. (C) Genes with commonly increased expression levels were assessed in isp-1(qm150), sod-2(ok1030), and nuo-1(ua1) mutants. (D) Venn diagram analysis performed with clk-1(qm30), glp-1(e2141), ife-2(ok306), and osm-5(p813) mutant strains. The number of genes (percentage) was depicted in the Venn diagram. A list of common genes for each condition is represented in Supplementary Table 1.

Evaluating the role of collagen in longevity using a C. elegans model

To determine whether the association between collagen proteins and long-lived circumstances observed was consistent with actual longevity, we conducted lifespan studies in a nematode model using human collagen proteins. We selected collagen types I (COL1A1), VII (COL7A1), and XXI (COL21A1) as experimental candidates based on the importance of the ECM for longevity (Teuscher et al., 2024). COL1A1, COL7A1, and COL21A1 share several common characteristics that are intrinsic to their functions within the ECM, despite their specific and distinct roles in various tissues (Goldberg et al., 2011; Oudart et al., 2017; Cao et al., 2022). All three collagen types are integral for maintaining the structural integrity and stability of tissues, ensuring mechanical resilience and proper tissue architecture. Functionally, they contribute to the cohesion and organization of the ECM, facilitating interactions between cells and their surrounding matrix. These interactions are crucial for tissue repair, regeneration, and homeostasis. Additionally, these collagens play a role in cellular signaling pathways that regulate cell proliferation, migration, and differentiation. By modulating the extracellular environment, COL1A1, COL7A1, and COL21A1 help maintain tissue function and integrity, supporting overall organismal health. To validate the anti-aging effects of these collagens, we synthesized COL1A1, COL7A1, and COL21A1 proteins using human peptides and confirmed >99% sequence consistency and >90% purity (Table 1).

We performed lifespan assays with COL1A1, COL7A1, and COL21A1 at a dose range of 0-160 ppm and confirmed significant lifespan extension with COL1A1 and COL7A1. In the lifespan assay with COL1A1, a significant increase in the average lifespan was observed (2.2-3.1%, 40 ppm; 5.7-7.5%, 80 ppm; 7.5-9.25%, 160 ppm; p value indicated) (Fig. 2A-2C,Supplementary Table 2). Remarkably, an increased mean lifespan was found with COL7A1 treatment (1.9-10.1%, 40 ppm; 4.8-12.8%, 80 ppm; 13.7-20.9%, 160 ppm; p-value listed; Fig. 2D-2F, Supplementary Table 2). In contrast to COL1A1 and COL7A1, COL21A1 showed no notable alteration in the lifespan (Fig. 2G-2I, Supplementary Table 2). To further investigate the effects of collagen, we evaluated various healthy-aging-related factors. To determine whether collagen treatment could attenuate the age-related decline in motility, we measured nematode body movement using locomotive speed and the number of body bends. COL1A1, and to a greater extent, COL7A1, greatly recovered organismal motility during locomotion (Fig. 3A) and bending movements (Fig. 3B). In addition, lifespan extension using collagen proteins did not affect the reproductive function of nematodes (Fig. 3C). Many anti-aging reagents extend lifespan and decrease fertility (Lucanic et al., 2017; Calabrese et al., 2024); however, COL1A1 and COL7A1 enhanced the lifespan and healthspan of normal progeny. Next, we estimated another healthspan-related factor, stress resistance. In accordance with the lifespan extension rate, COL7A1 markedly improved the resistance to acute oxidative stress (Fig. 3D) and thermotolerance (Fig. 3E). Intriguingly, although oxidative stress resistance increased, collagen proteins did not increase, but rather slightly decreased, the activity of the antioxidant enzymes SOD (Fig. 3F) and catalase (Fig. 3G). Moreover, because of delayed senescence in C. elegans, collagen proteins, especially COL7A1, remarkably reduced the accumulation of the age-related pigment lipofuscin (Fig. 3H) and TGs (Fig. 3I).

Figure 2. The role of collagen peptides in the Caenorhabditis elegans lifespan. (A-C) Effects of COL1A1 (40, 80, 160 ppm) versus vehicle (black) on lifespan (p-value listed, log-rank test); the same color coding is assigned to all subsequent panels. (D-F) Kaplan-Meier survival curve with COL7A1 (40, 80, 160 ppm) (p-value listed, log-rank test). (G-I) Independent lifespan assay with COL21A1 (40, 80, 160 ppm) (p-value listed, log-rank test). Lifespan assay data are presented in Supplementary Table 1.

Figure 3. COL7A1 promotes healthy aging in C. elegans. Effects of COL1A1, COL7A1, and COL21A1 versus vehicle on (A) average speed (***p<0.001 and ****p<0.0001 versus the vehicle group, one-way analysis of variance [ANOVA], n=20 worms×three assays each), (B) number of body bends (**p<0.01 and ****p<0.0001 versus the vehicle group, one-way ANOVA, n=20 worms×three assays each), (C) number of progeny (p>0.05, Student’s t-test, three independent measurements), (D) oxidative stress resistance (**p<0.01 and ****p<0.0001 versus the vehicle group, one-way ANOVA, n=20 worms×nine measurements each), (E) thermotolerance (*p<0.05 and ****p<0.0001 versus the vehicle group, one-way ANOVA, n=20 worms×nine measurements each), (F) superoxide dismutase (SOD) activity (*p<0.05 and **p<0.01 versus vehicle, Student’s t-test, n=3 worm pellets), (G) catalase activity (*p<0.05 and **p<0.01 versus vehicle, Student’s t-test, n=3 worm pellets), (H) lipofuscin content (**p<0.01 and ****p<0.0001 versus the vehicle group, one-way ANOVA, n=20 worms×three assays each), and (I) triglyceride (TG) content ***p<0.001 and ****p<0.0001 versus the vehicle group, one-way ANOVA, n=3 worm pellets). Error bars represent the mean ± standard deviation (sd).

Exploration of the roles of collagen in the aging process using skin fibroblasts

RNA-seq analysis after 160 ppm collagen peptide treatment of HDFs revealed that COL7A1 attenuated cellular metabolic responses and showed a dramatic increase in collagen complex-related gene expression levels compared to COL1A1 and COL21A1 (Fig. 4A). To investigate the effect on collagen synthesis, we determined the amount of type I collagen secreted into the culture media of HaCaT cells stimulated with collagen peptides. In accordance with the altered gene expression levels, COL7A1 induced a 1.7-fold increase in the synthesis of collagen type I compared to COL1A1 and COL21A1 (Fig. 4B). To further explore the molecular mechanisms underlying COL7A1-mediated longevity, we examined the expression of skin-senescence-associated genes. COL7A1 induced the expression of collagen-containing ECM genes and attenuated the expression of genes involved in protein metabolism and phosphorylation (Fig. 4C, 4D). In addition, collagen type I synthesis was increased in a dose-dependent manner by treatment with COL7A1 (Fig. 4E).

Figure 4. Effects of COL7A1 on extracellular matrix gene expression and collagen synthesis. (A) Heatmap of COL7A1-, COL1A1-, or COL21A1-treated human dermal fibroblasts (HDFs) and a description. (B) Relative procollagen I production after treatment with 160 ppm of collagen peptides. (C) Differentially expressed genes (DEGs) in COL7A1-treated HDFs. (D) Volcano plot of COL7A1-treated HDFs compared to vehicle groups. (E) Relative procollagen synthesis after treatment with 80 and 160 ppm of COL7A1. ***p<0.001 versus the vehicle group, one-way ANOVA. Error bars represent the mean ± sd.

Our investigation established collagen as a promising biotarget for longevity, indicating its potential to address the decline in both organismal and skin senescence. This discovery fills a significant gap in accessible therapeutic targets, particularly for interventions where safety and minimal side effects are crucial. Although collagen shows potential as a therapeutic target, its ability to prevent senescence-associated factors during the aging process, before the onset of age-related decline warrants further investigation. This highlights the need for further research to fully understand the capacity of collagen to promote healthy aging.

Collagen, a major component of the ECM, plays a crucial role in maintaining skin integrity and resilience. Structurally, collagens are composed of polypeptide chains that form triple helices, which are the hallmarks of collagen proteins and the components that confer strength and durability (Sorushanova et al., 2019). COL1A1, COL7A1, and COL21A1 have distinct structural and functional characteristics tailored to their specific roles in the ECM. COL1A1 is the most abundant collagen in the human body, comprising two α1(I) chains and one α2(I) chain, forming a triple helix structure (Gildner et al., 2014). These helices aggregate to create long rigid fibrils that provide tensile strength and are primarily found in the skin, bone, tendons, and ligaments. Functionally, COL1A1 imparts mechanical strength, supports tissue repair and regeneration, and serves as a scaffold for cell attachment, thus maintaining overall tissue morphology and function. In contrast, COL7A1 composed of three identical α1(VII) chains, forms anchoring fibrils that connect the epidermal basement membrane to the underlying dermis at the dermal-epidermal junction (DEJ). This anchoring is crucial for maintaining skin integrity, preventing blistering, and ensuring structural stability (Gretzmeier et al., 2022). COL7A1, also known as bonding collagen, is involved in wound healing, particularly in re-establishing the DEJ after injury. Deficiencies or mutations in COL7A1 can lead to dystrophic epidermolysis of the bullosa, which is characterized by skin fragility and blistering. COL21A1, a fibril-associated collagen with interrupted triple helices (FACIT), features shorter triple helical domains interspersed with non-helical regions (Tuckwell, 2002). Unlike fibrillar collagens, FACITs do not form large fibrils, but are associated with the surface of collagen fibrils, influencing their interactions and organization. COL21A1 is present in various tissues, including the skin, blood vessels, and cornea, where it modulates fibril organization, contributes to tissue flexibility and strength, and stabilizes the ECM in dynamically changing environments, such as the vascular system. Among these, COL7A1 has garnered significant interest because of its unique properties and potential implications in skin aging. COL7A1 is a fibrillar collagen primarily found in the anchoring fibrils of the DEJ, where it facilitates attachment of the epidermis to the underlying dermis. This anchoring function is vital for maintaining the skin architecture and function. Recent studies have suggested that the degradation or insufficient production of COL7A1 contributes to the deterioration of the DEJ, leading to compromised skin stability and the manifestation of signs of aging (Chung et al., 2019). Furthermore, COL7A1 has been implicated in wound healing and tissue regeneration, indicating its broad roles in skin health and repair (Lwin and McGrath, 2022). While all three collagens contribute to the structural integrity of the ECM, COL1A1 provides overall tensile strength, COL21A1 modulates fibril interactions and ECM stabilization, and COL7A1 anchors the epidermis to the dermis, ensuring skin stability, particularly in tissues that require flexibility and resilience. This anchoring is crucial for maintaining skin integrity, preventing blistering, and ensuring structural stability (Gretzmeier et al., 2022).

In this study, COL7A1 extended the lifespan of the aging model organism C. elegans in a dose-dependent manner and recovered the senescence-associated decline in motility. Intriguingly, COL7A1 enhanced the resistance to oxidative and thermal stress without increasing antioxidative enzyme activity. This may be because COL7A1 treatment increased the expression level of collagen cuticle protein, which acts as a barrier against external stimuli. Moreover, RNA-seq results showed that COL7A1 increased DEJ- and barrier-function-related gene expression levels in skin fibroblasts, as well as mediators of age-related skin dysfunction. COL7A1, with elastic fibers, plays an important role in the connectivity of the dermis and epidermis and in the mechanism that maintains skin structure, especially the papillary layer, thereby preventing wrinkles and sagging and contributing to skin tightening (Tohgasaki et al., 2022). Moreover, because of its low molecular weight and its fibrils anchoring the DEJ on the dermal side of the dermis interface (Chung and Uitto, 2010), COL7A1 can penetrate the dermis. Understanding the mechanisms underlying the involvement of COL7A1 in skin aging may open new avenues for the development of targeted anti-aging therapies. In conclusion, we identified COL7A1 as a therapeutic target for both organismal and skin senescence. COL7A1 is commonly associated with longevity pathways and significantly increases collagen/ECM gene expression and collagen synthesis, resulting in an extended healthspan (Fig. 5A). This study advances the development of accessible and commonly applicable anti-aging interventions targeting COL7A1 (Fig. 5B). To fully understand the potential of COL7A1 VII (referred to as bonding collagen T7), extensive validation studies, assessments of its curative capabilities, differentiation from related conditions, a detailed understanding of its underlying mechanisms, and exploring various therapeutic avenues are required. Addressing these challenges will substantially enhance our understanding and management of healthy aging and skin senescence, ultimately contributing to the health and well-being of the aging population.

Figure 5. The COL7A1-related anti-aging pathway. (A) The mechanistic pathway of healthspan extension via COL7A1. (B) The role of COL7A1 in skin integrity in the dermal-epidermal junction (DEJ).

This study was supported by Konkuk University in 2024. The analysis of COL7A1 protein was supported by the Gyeonggido Business & Science Accelerator (GBSA).

The authors declare no conflict of interest associated with this manuscript.

Conception and design: Juewon Kim, Woo-Young Seo, Donghyun Cho. Collection and assembly of data: Juewon Kim, Hyeryung Kim, Eunji Lee. Data analysis and interpretation: Juewon Kim, Hyeryung Kim, Eunji Lee, Woo-Young Seo. Manuscript writing: Juewon Kim, Woo-Young Seo. Final approval of the manuscript: All authors. Accountable for all aspects of the work: All authors.