Urinary bladder extracellular matrix hydrogels and matrix-bound vesicles differentially regulate central nervous system neuron viability and axon growth and branching

Abstract

Central nervous system neurons often degenerate after trauma due to the inflammatory innate immune response to injury, which can lead to neuronal cell death, scarring, and permanently lost neurologic function. Extracellular matrix bioscaffolds, derived by decellularizing healthy tissues, have been widely used in both preclinical and clinical studies to promote positive tissue remodeling, including neurogenesis, in numerous tissues, with extracellular matrix from homologous tissues often inducing more positive responses. Extracellular matrix hydrogels are liquid at room temperature and enable minimally invasive extracellular matrix injections into central nervous system tissues, before gelation at 37℃. However, few studies have analyzed how extracellular matrix hydrogels influence primary central nervous system neuron survival and growth, and whether central nervous system and non-central nervous system extracellular matrix specificity is critical to neuronal responses. Urinary bladder extracellular matrix hydrogels increase both primary hippocampal neuron survival and neurite growth to similar or even greater extents, suggesting extracellular matrix from non-homologous tissue sources, such as urinary bladder matrix-extracellular matrix, may be a more economical and safer alternative to developing central nervous system extracellular matrices for central nervous system applications. Additionally, we show matrix-bound vesicles derived from urinary bladder extracellular matrix are endocytosed by hippocampal neurons and positively regulate primary hippocampal neuron neurite growth. Matrix-bound vesicles carry protein and RNA cargos, including noncoding RNAs and miRNAs that map to the human genome and are known to regulate cellular processes. Thus, urinary bladder matrix-bound vesicles provide natural and transfectable cargoes which offer new experimental tools and therapeutic applications to study and treat central nervous system neuron injury.

Regenerative medicine, organ bioengineering and transplantation

“…These constructs have the advantage of maintaining tissue‐specific cell functions and phenotypes to induce host tissue remodelling. Previous studies 23–38 have had success in obtaining aECM scaffolds from virtually all mammalian organs. They preserve the native vasculature for adequate perfusion of constructs able to withstand physiological blood pressures, something that has been a challenge to RM methods relying on progenitor cell embryogenesis 39,40 .…”

Tissue and organ decellularization in regenerative medicine

“…The implantation of large segments (>24cm 2 ) of urinary bladder into porcine bladder showed infiltration of smooth muscle cells and promoted angiogenesis after 30 days . Vesicles derived from urinary bladder ECM had a positive effect on neuron neurite growth and on spinal cord injury repair . Urinary bladder‐derived ECM also had a better effect on the treatment of open wounds when compared with conventional therapies .…”

“…Urinary bladder has been one of the first organs selected for decellularization. Recent studies on ECM derived from decellularized bladder have indicated a beneficial effect on neuron survival, stem cells, spinal cord, and open wounds . Urinary bladder‐derived ECM has shown greater advantage than cardiac‐derived ECM in remodelling and for attracting site‐specific cells (cardiomyocytes) after implantation .…”

“…Recent studies on ECM derived from decellularized bladder have indicated a beneficial effect on neuron survival, stem cells, spinal cord, and open wounds. [49][50][51][52] Urinary bladder-derived ECM has shown greater advantage than cardiac-derived ECM in remodelling and for attracting sitespecific cells (cardiomyocytes) after implantation. 53 The implantation of large segments (>24cm 2 ) of urinary bladder into porcine bladder showed infiltration of smooth muscle cells and promoted angiogenesis after 30 days.…”

“…54 Vesicles derived from urinary bladder ECM had a positive effect on neuron neurite growth and on spinal cord injury repair. 50,51 Urinary bladder-derived ECM also had a better effect on the treatment of open wounds when compared with conventional therapies. 49 Bioproducts made from urinary bladder-derived ECM are available in different formulations such as sheets (Cytal ® Burn Matrix, also marketed as MatriStem ® Burn Matrix, ACELL (Columbia, USA); the product is applied directly on wounds), powder (MicroMatrix ® , ACELL, Columbia, USA) and hydrogels (not available commercially).…”