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Evolutionary trajectory of pattern recognition receptors in plants

Plant cell-surface receptors that are known to participate in immunity, development, and reproductive processes include the LRR-, G-lectin-, Wall-associated kinase (WAK)-, Domain of Unknown Function 26 (Duf26)-, L-lectin-, Lysin motif (LysM)-, and Malectin-containing RLKs and RLPs (Fig. 1a–h). There are additional RLK families with different ectodomains, such as the proline-rich extensin-like receptor kinases (PERKs) and thaumatin-like protein kinases (TLPKs)9,13. However, their function in immunity is not well-characterized. Cell-surface receptors with LRR-, G-lectin-, WAK-, and LysM-ectodomains have been reported to recognise PAMPs, while others perceive self-molecules or unidentified ligands (Fig. 1h; Supplementary Fig. 1). Recognition of the diverse array of ligands is likely to be accomplished by variable structures and combinations of different ectodomains (Fig. 1a–g). To trace the origins of different receptor classes within the plant lineage, we first identified RLKs and RLPs in 350 genomes from Glaucophyta, red algae, green algae, Bryophytes, and Tracheophytes. We define here RLKs as any proteins with both 1–2 TMs and KDs, and RLPs as any protein with 1–2 TMs, but lack KDs. In total, we identified 177,645 RLKs, almost up to 70% of which possess either LRR-, G-lectin-, WAK-, Duf26-, L-lectin-, LysM-and Malectin-ectodomains (Fig. 1i). Next, we searched for proteins with these ectodomains and TMs that lack KDs and found 41,144 RLPs (Fig. 1j). We further examined which of the identified RLKs and RLPs families are likely to be involved in immunity. A previous report suggested a positive correlation between the gene family sizes of cell-surface immune receptors and intracellular immune receptors (the NB-ARC family) across the angiosperms4. We examined the correlation between the relative size (%; number of identified genes in the family/numbers of searched genes × 100; see methods) of the RLK families, the RLPs families, and the NB-ARC family in each genome. Notably, most RLK families (except for the LysM-RLKs) exhibit positive correlations with the NB-ARC family, while most RLP families (except for the LRR-RLPs) do not exhibit positive correlation with the NB-ARC family (Main Fig. 1k). Furthermore, we checked the expression level of these receptor families in Arabidopsis thaliana during immunity. Notably, the RLKs, except for LRR-and Malectin-RLKs, generally exhibit higher expression levels compared to the RLPs during immunity (Main Fig. 1k; Supplementary Fig. 2). These data collectively suggest that the RLKs are more likely to be involved in immunity than the RLPs.

Next, we examined the presence or absence of ectodomains (LRR-, G-lectin-, WAK-, Duf26-, L-lectin-, LysM-and Malectin-ectodomains lacking TM or KD; ectodomain-only proteins), RLPs (TM-bound ectodomains) and RLKs (ectodomains encompassing both TM and KD) in the plant lineage (Fig. 2; Supplementary Fig. 3; Supplementary Data 1a–c). Ectodomains exhibit an ancient heritage, with LRR-, WAK-, LysM-, Malectin-, and L-lectin-domains dating back to the era of Glaucophyta. Similarly, relatively ancient counterparts such as LRR-RLPs, WAK-RLPs, LysM-RLPs, Malectin-RLPs, and L-lectin-RLPs are found in both Glaucophyta and Rhodophyta. In contrast, RLKs emerged more recently. Green algae harbour WAK-RLKs, Malectin-RLKs, and G-lectin-RLKs, and LysM-RLKs, L-lectin-RLKs, and Duf-26-RLKs are exclusive to Embryophytes (Fig. 2). Except for LRR-RLPs, all six families of RLP are basal to the RLK families.

DNA Targeting Drug Shows Efficacy for Colorectal Cancer

Colorectal cancer (also called bowel cancer) typically develops in the large bowel (colon) or rectum. Recent studies have shown significant rises in the number of colorectal cancer cases, particularly those in young adults. As we discussed earlier, the recently released estimated cancer statistics for 2024 predict colorectal cancer as the leading cause of mortality in men under 50 and the second-leading cause of mortality in women. Additionally, experts predict over 150,000 new cases of colorectal cancers this year.

To combat these troubling figures, ongoing research focused on the prevention and treatment of colorectal cancers remains a high priority and urgent need. This includes data recently published in Science Advances which demonstrates pre-clinical efficacy for a new treatment approach.

The study involves genetic material known as microbial or mislocalized DNA. This type of DNA arrises from cells that become damaged, thus no longer providing the correct genetic instructions. Damaged DNA can elicit various reactions in the body, including activating the immune response. Damaged DNA can therefore influence how the body responds to diseases, including colorectal cancer.

Researchers discover epigenetic status determines metastasis

Scientists from the German Cancer Research Center (DKFZ) and Heidelberg University have investigated in mice how spreading tumor cells behave at the site of metastasis. Some tumor cells immediately start to form metastases. Others leave the blood vessel and may then enter a long period of dormancy. What determines which path the cancer cells take is their epigenetic status. This was also confirmed in experiments with human tumor cells. The results of the study could pave the way for novel diagnostic and therapeutic applications.

The work appears in Nature Cancer.

What makes cancer so dangerous? Cancer cells that leave the primary tumor to reach distant sites of the body where they may grow into daughter tumors, called metastases. While most primary tumors can be effectively treated, metastases are the real danger. Oncologists estimate that more than 90% of all cancer deaths in are due to metastases.

Gene Editing Technology Approved in US for Sickle Cell Disease

A gene editing tool using a system known as CRISPR-Cas9 has recently been approved by the U.S. Food and Drug Administration (FDA) for sickle cell disease. The drug is known as Casgevy and the media has hailed this treatment as a ‘cure’ for sickle cell anemia patients. While it is still unclear if the drug completely cures these patients, clinical trials show exciting efficacy.

Sickle cell disease is a genetic blood disorder affecting thousands of US citizens. Many of these patients are African American and Hispanic. In sickle cell disease, hemoglobin, a protein in red blood cells that helps carry oxygen throughout the body, is mutated. As a result, blood cells change shape in the form of a sickle, giving the disease its name. Unfortunately, the mutated cells cause disruption of blood flow and prevent other blood cells from delivering oxygen to the body. This disease is extremely rare and can lower the quality of life in patients. Previously, there were limited treatments options including transfusions and medications for pain management. However, Casgevy provides a new option to help treat the patient and relieve pain for over a year after a single treatment.

One-time treatment using Casgevy improved life quality for sickle cell patients. A single-arm trial was conducted at multiple health centers in adults and adolescents. These patients were screened for two vaso-occlusive crises (VOCs) which are described as severely painful events due to a lack of oxygen delivery from sickle cell blood cells blocking blood flow. The primary measure of success in the trial was the number of VOCs after treatment. In total, 44 patients received Casgevy and 33 were able to follow up and be evaluated. Of the 33 patients that made it through the trial, 29 of them did not experience any VOCs for 12 months. This is a 93.5% success rate based on the number of patients that were analyzed. All 44 patients were able to successfully undergo treatment without any graft rejection. In addition, researchers concluded that this treatment was not only effective, but safe with few side effects.

CRISPR off-switches: A path towards safer genome engineering?

Using CRISPR, an immune system bacteria use to protect themselves from viruses, scientists have harnessed the power to edit genetic information within cells. In fact, the first CRISPR-based therapeutic was recently approved by the FDA to treat sickle cell disease in December 2023. That therapy is based on a highly studied system known as the CRISPR-Cas9 genetic scissor.

However, a newer and unique platform with the potential to make large-sized DNA removals, called Type I CRISPR or CRISPR-Cas3, waits in the wings for potential therapeutic use.

A new study from Yan Zhang, Ph.D., Assistant Professor in the Department of Biological Chemistry at the University of Michigan Medical School, and her collaborators at Cornell University develops off-switches useful for improving the safety of the Type I-C/Cas3 gene editor. The study, “Exploiting Activation and Inactivation Mechanisms in Type I-C CRISPR-Cas3 for 3 Genome Editing Applications,” is published in the journal Molecular Cell.

Healthy eating and activity reverse aging marker in kids with obesity, study finds

A genetic marker linked to premature aging was reversed in children with obesity during a six-month diet and exercise program, according to a recent study led by the Stanford School of Medicine.

Children’s telomeres—protective molecular “caps” on the chromosomes—were longer during the weight management program, then were shorter again in the year after the program ended, the study found. The research was published last month in Pediatric Obesity.

Like the solid segment at the end of a shoelace, telomeres protect the ends of chromosomes from fraying. In all people, telomeres gradually shorten with aging. Various conditions, including obesity, cause premature shortening of the telomeres.

Optimizing Gene Editing with PARP1 CRISPR Plasmids

Gene editing is revolutionizing the understanding of health and disease, providing researchers with vast opportunities to advance the development of novel treatment approaches. Traditionally, researchers used various methods to introduce double strand breaks (DSBs) into the genome, including transactivator-like effectors, meganucleases, and zinc finger nucleases. While useful, these techniques are limited in that they are time and labor intensive, less efficient, and can have unintended effects. In contrast, the clustered regularly interspaced short palindromic repeat (CRISPR)-associated protein-9 (Cas9) system (CRISPR/Cas9) is among the most sensitive and efficient methods for creating DNA DSBs, making it the leading gene editing technology.

CRISPR/Cas9 is a naturally occurring immune protective process that bacteria use to destroy foreign genetic material.1 Researchers repurposed the CRISPR/Cas9 system for genetic engineering applications in mammalian cells, exploiting the molecular processes that introduce DSBs in specific sections of DNA, which are then repaired to turn certain genes on or off, or to correct genomic errors with extraordinary precision.2,3 This technology’s applications are far reaching, from cell culture and animal models to translational research that focuses on correcting genetic mutations in diseases such as cancer, hemophilia, and sickle cell disease.4

Researchers exploit plasmids, the small, closed circular DNA strands native to bacteria, as delivery vehicles in CRISPR/Cas9 gene editing protocols. Plasmids shuttle the CRISPR/Cas9 gene editing components to target cells and can be manipulated to control gene editing activity, including targeting multiple genes at a time. Plasmids can also deliver gene repair instructions and machinery. For example, poly (ADP-ribose) polymerase 1 (PARP1) is an enzyme that drives DNA repair and transcription.5 It is a critical aspect of CRISPR/Cas9 gene editing technology in part because it helps repair the DSBs created by the CRISPR/Cas9 system. PARP1 CRISPR plasmids can edit, knockout, or upregulate PARP1 gene expression depending on the specific instructions encoded in the plasmid.

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