An antimicrobial peptide of the cathelicidin family that provides innate immune defense by killing pathogens and modulating inflammation and wound healing.
Scientists tweaked the human antimicrobial peptide LL-37 to make versions that target specific bacteria while being less harmful to human cells. By changing the balance of charged and water‑repelling parts of the molecule, they created a new peptide called merecidin that can kill drug‑resistant Staph infections in an insect model without hurting the host.
Scientists pulled 14 positively‑charged peptides out of a soy protein hydrolysate and found they act like the human peptide LL‑37: they kill or inhibit microbes, neutralize bacterial toxins, and boost blood‑vessel growth, all without damaging red blood cells in lab tests. This suggests soy‑derived peptides could become natural immune‑support or tissue‑repair ingredients, but they’ve only been tested in petri dishes, not people.
Ogunsakin. Olalekan O; Sriyotha. Phanuwat P; Burns. Taylor T; Hottor. Tete T; McCaskill. Michael M
In lab tests, high levels of alcohol lowered the active form of vitamin D and the antimicrobial peptide LL‑37 in lung and immune cells, which could weaken lung defenses. Adding diallyl disulfide (a garlic‑derived compound) restored LL‑37 levels back to normal, suggesting it can counteract alcohol‑induced damage in these cells.
Zhang. Jing J; Guo. Ming M; Huang. Zhi-Xiang ZX; Bao. Rong R; Yu. Qian Q; Dai. Ming M; Wang. Xin X;...
In a mouse study, giving the active form of vitamin D (calcitriol) together with the TB drug pyrazinamide lowered the amount of bacteria in the lungs and spleen more than the drug alone. The combo also reduced lung damage, shifted the immune response toward less inflammation, and dramatically boosted the body's own antimicrobial peptide LL‑37 (and another peptide, mBD2). Vitamin D by itself didn’t fight the infection much, but it helped the drug work better and turned on natural defenses.
Cho. Young Y; Mitchell. Reed R; Paudel. Sharada S; Feltham. Tyler T; Schon. Lew L; Zhang. Zijun Z
In people with diabetes, the stem cells that help repair tissue also lose some of their ability to fight bacteria because they make less of the natural antibiotic peptide LL‑37 and other immune factors. This makes bacterial growth easier and weakens immune cells that normally eat bacteria.
Researchers found three rice‑bran‑derived peptides (RBP‑LRR, RBP‑EKL, RBP‑SSF) that can boost skin cell growth, blood‑vessel formation, and cell movement in lab dishes, acting much like the natural peptide LL‑37. These effects suggest the peptides could help wounds close faster, but the work was done only in cell cultures, not in people.
Researchers found that a naturally occurring skin peptide called lugdunin not only kills Staph aureus directly but also boosts the skin’s own defenses by making cells produce more of the antimicrobial peptide LL‑37 and other immune signals. When used together with other skin‑derived peptides, lugdunin cuts down bacterial colonisation even more, and it does this through a known immune pathway (TLR/MyD88). This suggests lugdunin could become a new topical tool for preventing or treating stubborn skin infections.
Hashemi. Marjan M MM; Holden. Brett S BS; Coburn. Jordan J; Taylor. Maddison F MF; Weber. Scott S; H...
The study shows that when bacteria become resistant to the antiseptic chlorhexidine, they also become much less sensitive to the antibiotic colistin, but their sensitivity to the natural antimicrobial peptide LL‑37 (and similar peptides) stays the same. This means using chlorhexidine (like mouthwash or skin wipes) probably won’t weaken LL‑37’s ability to kill these bugs, though it could help create colistin‑resistant strains.
Ersoy. Selvi C SC; Abdelhady. Wessam W; Li. Liang L; Chambers. Henry F HF; Xiong. Yan Q YQ; Bayer. A...
The study shows that adding sodium bicarbonate (baking‑soda) to lab tests can make some MRSA bacteria become sensitive again to common antibiotics like oxacillin and cefazolin, especially when the natural immune peptide LL‑37 is present. This suggests a possible way to treat certain MRSA infections with cheaper, less toxic drugs, but it’s still early‑stage research and not a ready‑to‑use protocol for people.
LL-37, a natural antimicrobial peptide, can break apart the outer shell of Kaposi's sarcoma‑associated herpesvirus, stopping the virus from infecting mouth‑lining cells in lab tests. The effect comes from the peptide acting directly on the virus, not on the human cells.
Choi. Jae Eun JE; Werbel. Tyler T; Wang. Zhenping Z; Wu. Chia Chi CC; Yaksh. Tony L TL; Di Nardo. An...
The study shows that Botox (onabotulinum toxin A or B) can directly stop mast cells from releasing inflammatory chemicals, which in turn blocks the skin redness and inflammation caused by the peptide LL‑37 in a rosacea model. This suggests Botox could be a useful treatment for stubborn rosacea by targeting the underlying mast‑cell activity.
Saporito. Paola P; Vang Mouritzen. Michelle M; Løbner-Olesen. Anders A; Jenssen. Håvard H
Researchers found that tiny pieces of the natural antimicrobial peptide LL‑37, especially KR‑12 and a modified version called VQ‑12V26, can better stop and break down Staphylococcus epidermidis biofilms, are gentler on skin cells and red blood cells, and even help skin cells heal faster in lab dishes. These findings hint that short peptide fragments could become safer, more effective topical treatments for wound care and infection prevention, though they’re still early‑stage and not yet ready for DIY use.
Scientists made shorter, more stable versions of the natural immune peptide LL‑37. Some of these new peptides kill a range of tough, drug‑resistant bacteria (the ESKAPE group) better than the original and cause less damage to red blood cells. One version, called 17tF‑W, cleared MRSA infections in mouse catheters and changed immune signals in the tissue.
Gunasekera. Sunithi S; Muhammad. Taj T; Strömstedt. Adam A AA; Rosengren. K Johan KJ; Göra...
Scientists tweaked a small piece of the human antimicrobial peptide LL-37 (called KR-12) by swapping some building blocks for alanine or lysine. They found that certain changes, especially swapping a glutamine at position 5 for lysine and an aspartic acid at position 9 for alanine or lysine, made the peptide up to eight times better at killing common germs like Staph, Pseudomonas, and Candida, without harming human cells. This shows the peptide can be fine‑tuned for stronger, safe antimicrobial action.
Wan. Min M; Tang. Xiao X; Rekha. Rokeya Sultana RS; Muvva. S S V Jagadeeswara Rao SSVJR; Brighenti....
The study shows that the inflammation molecule PGE2 can block the vitamin‑D‑driven production of the antimicrobial peptide LL‑37 in human immune cells, which weakens the body’s ability to fight tuberculosis. This effect is strongest through the EP2 and EP4 receptors, and using an EP4‑activating drug makes the infection worse, while blocking EP4 might help. For biohackers, it suggests that high PGE2 levels (from certain diets or inflammation) could reduce the benefits of vitamin D supplements for immunity, and that lowering PGE2 or blocking EP4 could be a strategy to boost LL‑37 and improve infection resistance.
Researchers made modified pieces of the natural peptide CXCL14 that can kill many harmful bacteria at low doses and don’t hurt human cells. Some of these tweaks also help common antibiotics work better against tough, drug‑resistant bugs and can stop or break down bacterial biofilms. The peptides also calm down inflammation in immune cells, hinting they could be useful as anti‑infection or anti‑inflammatory agents, but they’ve only been tested in the lab so far.
Souza. L M P LMP; Nascimento. J B JB; Romeu. A L AL; Estrada-López. E D ED; Pimentel. A S AS
The study shows that the antimicrobial peptide LL‑37 can slip into lung surfactant quickly, but it gets stuck to the surfactant’s charged head groups, which neutralizes its ability to kill bacteria. Adding tiny particles made of sodium cholate protects the peptide, letting it move through the surfactant without losing its charge and without damaging the surfactant itself. This suggests a way to deliver LL‑37 (and similar peptides) to the lungs more effectively.
Schrumpf. Jasmijn A JA; Ninaber. Dennis K DK; van der Does. Anne M AM; Hiemstra. Pieter S PS
The study shows that a protein called TGF‑β1, which is higher in people with COPD, can block vitamin D’s ability to boost the antimicrobial peptide LL‑37 in airway cells. It does this by increasing an enzyme that breaks down vitamin D and by lowering other natural defense proteins. So even if you take vitamin D, high inflammation may limit its lung‑protective benefits.
Scientists found that certain positively‑charged peptides from a soy protein hydrolysate can neutralize bacterial endotoxin (LPS) and stimulate blood‑vessel growth, much like the well‑known peptide LL‑37, and they don’t damage red blood cells at high concentrations. While the work is still in test‑tube experiments, it suggests soy‑derived supplements might help lower inflammation from gut‑derived toxins and support tissue repair, though exact doses for people aren’t known yet.
The study shows that a natural protein called cathelicidin (LL‑37 in humans, CRAMP in mice) helps protect heart cells from dying after a heart attack. In mice, giving the peptide reduced heart damage, while mice lacking it had bigger injuries. In people who had a heart attack, lower blood levels of LL‑37 were linked to worse outcomes over a year.