Researchers from Wrocław Tech and Genentech have found a way to prevent a dying cell from breaking apart. They used pores that form in the cell membrane. These pores allow compounds that inhibit pyroptosis—a rapid, inflammatory form of cell death—to enter the cell. The findings have just been published in Nature.

The paper is the result of collaboration between the team led by Professor Marcin Poręba from the Faculty of Chemistry at Wrocław University of Science and Technology and the group led by Professor Vishva M. Dixit from Genentech, one of the world’s leading biotechnology companies.

One of the two co-first authors who contributed equally to the study is Dr Katarzyna Groborz, who completed her doctorate at Wrocław Tech before taking up a postdoctoral fellowship at Genentech. The other is Melissa E. Truong. Professor Poręba and Professor Dixit are the paper’s corresponding authors.

“The path from basic research funded by Poland’s National Science Centre, through a young researcher’s doctorate and international postdoctoral fellowship, to a research partnership with Genentech shows how science of global significance is created. This is the model we want to strengthen at Wrocław Tech: strong teams, the development of early-career researchers, international collaboration and research with genuine potential for practical application,” says Professor Arkadiusz Wójs, Rector of Wrocław University of Science and Technology.

Professor Poręba’s doctoral students Julia Nguyen and Małgorzata Kalinka also participated in the project, contributing to the synthesis of the inhibitors and their kinetic analysis. Another co-author is Professor Marcin Drąg, the developer of the HyCoSuL technology used to determine the substrate preferences of the caspases studied.

A cellular alarm

“Pyroptosis is one of the ways in which the body defends itself against infections and other threats,” explains Professor Marcin Poręba from Wrocław University of Science and Technology. “It is a controlled mechanism of cellular self-destruction accompanied by the activation of a powerful inflammatory response.”

During this process, enzymes known as inflammatory caspases are activated. In humans, these are caspases-1, -4 and -5. They act like molecular scissors, cleaving a protein called gasdermin D. The fragments released in this way assemble to form large pores in the cell membrane.

The resulting openings allow substances including the cytokines IL-1β and IL-18 to escape from the cell and alert the immune system. The cell begins to swell and ultimately ruptures.

“This response helps the body combat a threat,” the Wrocław Tech researcher explains. “The problem arises when pyroptosis becomes excessive or uncontrolled. It can then intensify inflammation and lead to tissue damage.”

A surprising result

Scientists have been exploring ways of inhibiting caspases for years. Previous clinical trials using inhibitors that readily enter cells did not, however, produce the expected results because the compounds were either toxic or insufficiently effective.

One problem was that these compounds also entered healthy cells, where they could inhibit caspases involved in other important processes.

The Wrocław Tech and Genentech teams turned this approach on its head. Rather than developing an inhibitor capable of crossing cell membranes as easily as possible, they focused on compounds that penetrate healthy cells very poorly.

Their starting point was a library of approximately one hundred compounds designed to target inflammatory caspases. One of them caught the researchers’ attention. Despite its extremely low permeability across an intact membrane, it effectively inhibited a process occurring inside the cell.

“The most interesting stage of the project began with an observation that initially seemed inconsistent with our assumptions. A compound with very low permeability across the membranes of healthy cells was able to inhibit a process taking place inside them. Rather than dismissing this result as an anomaly, we hypothesised that the mechanism of pyroptosis itself opened a route into the cell for the compound,” explains Professor Marcin Poręba from the Faculty of Chemistry.

The researchers proposed that the inhibitor enters the cell through the first pores formed by gasdermin D. Once inside, it blocks caspases and prevents the formation of further pores. It also reduces cytokine release.

The pores therefore become gateways found only in cells in which pyroptosis has already begun.

A window for rescue

One of the most extensively studied compounds was an inhibitor designated KGR-3. It inhibited pyroptosis triggered by caspases-1 and -4 and reduced the release of IL-1β.

“It did not, however, protect cells against apoptosis, which is another form of programmed cell death,” Professor Poręba explains. “Gasdermin D pores do not form during apoptosis. This was one piece of evidence that these openings were what enabled the inhibitor to reach its target.”

Further evidence came from dyes that cannot cross intact membranes. The researchers detected the dyes inside cells rescued from pyroptosis. This meant that the membrane had opened temporarily, but the cell had not ruptured.

“Once the caspases have been blocked, no further pores are formed. The existing damage can then be removed by the cell’s natural repair machinery, which involves the ESCRT protein complex,” Professor Marcin Poręba adds.

Importantly, the inhibitor did more than merely delay cell death. Some of the cells genuinely survived and retained their ability to continue growing. In one experiment, the researchers monitored their growth for 12 days.

The protective effect was also observed when the inhibitor was added several hours after pyroptosis had been initiated. This means that there is a short window between the formation of the first pores and the cell’s rupture during which the entire process can still be stopped.

Testing in a living organism

The next stage involved testing a compound designated KGR-53P. The scientists first confirmed its activity in mouse immune cells. Although the inhibitor penetrated healthy cells very poorly, it reduced both cell death and the release of IL-1β and IL-18.

The researchers then conducted a study in a mouse model of endotoxic shock. The animals were given bacterial lipopolysaccharide, which triggers a very strong inflammatory response. Blood levels of IL-1β and IL-18 were markedly lower in mice that also received KGR-53P.

The findings therefore indicate that a compound with poor permeability in healthy cells can reach caspases through gasdermin D pores and reduce the inflammatory response in a living organism as well.

Not a drug—at least, not yet

“These findings do not mean that we have already developed a treatment for sepsis or other inflammatory diseases,” says Professor Marcin Poręba.

KGR-3 and KGR-53P are research compounds that require further optimisation.

“KGR-53P was rapidly cleared from the body. We also observed increased levels of liver enzymes, although it is not yet known whether this resulted from the compound acting on other molecular targets,” the Wrocław Tech scientist explains.

The authors nevertheless emphasise the potential of the strategy itself. It may support the search for treatments for diseases associated with excessive pyroptosis and a powerful inflammatory response. The paper mentions sepsis, acute respiratory distress syndrome and COVID-19 among the possible examples.

The discovery therefore opens up a new avenue of research, although a long road remains before the method could potentially be used in patients.

It all began at Wrocław Tech

The chemical and enzymological part of the project began in Professor Marcin Poręba’s team at the Faculty of Chemistry of Wrocław University of Science and Technology. This was where the design principles for the inhibitors were developed, the compound library was prepared and the compounds’ interactions with caspases were investigated.

At Wrocław Tech, Dr Katarzyna Groborz developed the inhibitors that formed the basis for the subsequent research. Her doctoral supervisor was Professor Marcin Drąg, with Professor Poręba serving as assistant supervisor. She later drew on the expertise in chemical biology, enzymology and cell death research acquired during her doctorate in her work at Genentech.

“The project’s most important discovery was demonstrating that pyroptosis can be stopped even after it has begun. We showed that there is a short therapeutic window during which caspase inhibition interrupts the process and enables cells to regain their ability to grow and divide. By using pores formed by gasdermin D, we were able to deliver inhibitors selectively to cells in which pyroptosis had already begun. The project combined several scientific disciplines, from chemical biology and cell biology to in vivo research,” says Dr Katarzyna Groborz, who played a key role in the project by conducting the cell-based studies. This is why Genentech is listed as her affiliation in the paper.

The Genentech team was responsible for, among other things, advanced cell models, pharmacokinetic studies, the preparation of compounds for administration and animal experiments.

The research conducted by the Wrocław Tech team was funded by Poland’s National Science Centre under Professor Marcin Poręba’s OPUS grant, “Investigating proteolytic mechanisms in pyroptosis, a programmed form of cell death that triggers an inflammatory response”.

Groborz K.M., Truong M.E., Stowe I., Wickliffe K.E., Lee B., Bauernfried S., Jones R.S., Plise E., Levy E.S., Kou P., Lee W.P., Zhang J., Budayeva H., Rose C.M., Nguyen J., Kalinka M., Drąg M., Kayagaki N., Newton K., Poręba M., Dixit V.M., „Gasdermin D-mediated delivery of caspase inhibitors to suppress pyroptosis”, „Nature”, 2026.