Cellular senescence is a phenomenon that normal cells cease to divide. Previously, senescence has been thought to have only positive effects. For example, senescence suppresses tumor progression. But a new study puts?forward?different?views. The study, recently published in the Journal of Cell Biology, shows that senescence also has negative effects. A protein called HMGB2 protein is involved in the expression of cytokines and chemokines during cellular senescence, a finding that would help scientists find ways to prevent the negative effects of cellular senescence. The study was led by Professor Rugang Zhang at The Wistar Institute. In the study, Prof. Zhang and colleagues looked at an important cellular structure called chromatin. During senescence, proliferation-promoting genes are silenced through the reorganization of chromatin into senescence-associated heterochromatin foci (SAHF). But at the same time, the expression of some genes that encode secreted factors such as cytokines and chemokines is increased. These factors are referred to as the senescence-associated secretory phenotype (SASP). Both cytokines and chemokines are small proteins that play key roles in immune response. An increase in the expression of these proteins may have harmful effects. Zhang's team found that during senescence, a protein termed HMGB2 prevents SAHF from silencing SASP genes and thus promotes their expression. Furthermore, loss of HMGB2 during senescence allows SAHF to silence SASP genes. In sum, inhibiting HMGB2 could help decrease the expression of unwanted secreted factors during senescence. Moreover, the study would help scientists find a way of suppressing the negative effects of senescence while promoting the positive effects of it. HMGB2 and other proteins like Recombinant ITGB7 can be offered by CusAb.
