Japanese researchers uncover “Super HGF” molecule that boosts muscle‑repair signaling
A new sulfur‑based compound dramatically strengthens a key muscle‑regeneration protein in lab and mouse studies, offering a fresh angle on age‑related muscle loss.
Why Muscles Lose Their Edge With Age
Even early in the aging process, skeletal muscles begin to shed strength and their capacity to bounce back after injury. Over time, scar tissue and fat can infiltrate muscle, and the fast‑twitch fibers that power rapid movements decline, making everyday tasks harder and threatening mobility.
The Body’s Built‑In Repair Team
Muscle regeneration relies on satellite cells, a type of stem cell that sits quiet beside muscle fibers until a repair signal arrives. When activated, these cells multiply and mature into new muscle cells, restoring damaged tissue.
A pivotal signal is hepatocyte growth factor (HGF). Although its name hints at liver function, HGF also awakens satellite cells by binding to the c‑met receptor on their surface. Normally, HGF is stored in the extracellular matrix and released during injury or mechanical stretch, where it latches onto c‑met and triggers the repair cascade.
Age‑Related Chemical Damage to HGF
Previous work from the same team showed that HGF can be chemically altered through nitration—a process that tacks a nitro group onto specific amino acids. The researchers pinpointed two crucial sites, Y198 and Y250, located within the region that contacts c‑met. Nitration at these spots weakens HGF’s ability to bind its receptor, effectively turning a well‑fitted key into a damaged one.
“HGF is not necessarily missing as we age,” explained Professor Ryuichi Tatsumi of Kyushu University’s Faculty of Agriculture. “Rather, it can be chemically altered after it is made.” This insight led the team to ask whether a strong antioxidant could shield HGF from nitration or even restore its function.
Testing Two Trisulfide Antioxidants
The scientists turned to two sulfur‑rich trisulfides: glutathione trisulfide (GSSSG) and lipoic acid trisulfide (LASSS). Trisulfides contain a chain of three sulfur atoms, giving them distinctive redox properties that have attracted interest for drug development.
In initial experiments, both compounds reduced nitration at Y198 and Y250, but the protection alone did not fully recover HGF’s receptor‑binding ability. To probe further, the researchers increased the trisulfide‑to‑HGF molar ratio from 1:4,000 to 1:8,000.
LASSS Creates a “Super HGF”
At the higher concentration, LASSS did more than block nitration—it dramatically enhanced HGF’s affinity for c‑met, more than doubling the binding strength compared with untreated HGF. The effect was especially pronounced at the Y198 site, where LASSS made HGF resistant to functional loss.
GSSSG, despite its earlier nitration‑reduction effect, did not boost receptor binding. “This exceeded our expectations,” Tatsumi noted. “LASSS does more than simply neutralize reactive molecules. It may interact directly with HGF and induce a subtle structural change, creating an enhanced ‘Super HGF’ form that binds c‑met more strongly and resists nitration.”
The team hypothesizes that LASSS subtly reshapes HGF’s three‑dimensional structure, improving its fit with the receptor. While stronger binding does not yet prove improved muscle regeneration, it opens a promising avenue for future research.
Mouse Tests Confirm Protective Action
To see whether LASSS works in living tissue, the researchers used a mouse model of muscle atrophy induced by tail suspension—a method that mimics the loss of weight‑bearing activity and triggers muscle deterioration. Mice pre‑treated with LASSS displayed significantly lower HGF nitration levels than untreated controls, indicating that the compound can protect the repair protein in vivo.
Again, GSSSG failed to show the same protective effect, underscoring the unique action of LASSS.
What Comes Next?
The findings, published in Scientific Reports, suggest that LASSS could become a tool for enhancing the body’s natural muscle‑repair signaling, potentially counteracting age‑related muscle wasting. Further studies will need to test whether “Super HGF” translates into actual improvements in muscle healing, strength, and functional outcomes.
For now, the discovery adds a fresh twist to the search for antioxidant‑based therapies that safeguard the proteins essential for tissue regeneration.
