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antimicrobial peptide

Defensin Alpha-1

Published evidence · coverage incomplete

Anatomy in the research

Anatomy evidence is still being assembled.

These are anatomical mentions in cited research—not established treatment targets or proof of benefit in people.

This publication has no anatomy passages that meet our source-linking checks yet. Read the available findings ↓

General anatomy view only. No peptide-specific structures are highlighted.

At a glance

What is it—and why does it matter?

An introduction is not yet available. The findings below address specific research questions, not a complete account of this peptide.

This published profile is a reference in progress. Findings retain their source context; missing topics are marked below.

What is it?

A molecule, not a product name.

Identity

The study objective was to assess whether DEFA1 is expressed in human platelets and megakaryocytes.

Sources[2]pubmedHuman platelets and megakaryocytes express defensin alpha 1.The aim of this study was to characterize the expression of defensin alpha 1 (DEFA1) in human platelets and megakaryocytes.
Source records
1
Independent studies
1

Evidence boundary: Applies only to the source-defined population, formulation, dose, and assessment period.

Exact passages, locators, and provenance
  1. supports · Source-backed record
    “The aim of this study was to characterize the expression of defensin alpha 1 (DEFA1) in human platelets and megakaryocytes.”

    Human platelets and megakaryocytes express defensin alpha 1. · Abstract

    pubmed:31116063:f5370144b41f:f5370144b41f

How does it work?

Target, response, and disposition.

Mechanism

Using an in vitro platelet-like particle system, MEG-01 cells were observed to transfer DEFA1 mRNA into differentiated PLPs.

Sources[2]pubmedHuman platelets and megakaryocytes express defensin alpha 1.The assay of ourin vitromodel of platelet-like particles (PLPs) revealed that MEG-01 cells could transfer DEFA1 mRNA to their differentiated PLPs.
Source records
1
Independent studies
1

Evidence boundary: Applies only to the source-defined population, formulation, dose, and assessment period.

Exact passages, locators, and provenance
  1. supports · Source-backed record
    “The assay of ourin vitromodel of platelet-like particles (PLPs) revealed that MEG-01 cells could transfer DEFA1 mRNA to their differentiated PLPs.”

    Human platelets and megakaryocytes express defensin alpha 1. · Abstract

    pubmed:31116063:f5370144b41f:f5370144b41f

Mechanism

Subcellular localization data indicate DEFA1 is associated with α-granules in platelets and MEG-01 cells, with additional cytoplasmic detection in MEG-01 cells.

Sources[2]pubmedHuman platelets and megakaryocytes express defensin alpha 1.DEFA1 co-localize with α-granules of platelets and MEG-01 cells, and was also detected in cytoplasm of MEG-01 cells.
Source records
1
Independent studies
1

Evidence boundary: Applies only to the source-defined population, formulation, dose, and assessment period.

Exact passages, locators, and provenance
  1. supports · Source-backed record
    “DEFA1 co-localize with α-granules of platelets and MEG-01 cells, and was also detected in cytoplasm of MEG-01 cells.”

    Human platelets and megakaryocytes express defensin alpha 1. · Abstract

    pubmed:31116063:f5370144b41f:f5370144b41f

Mechanism

After secretion, DEFA1 is reported to rebind to the platelet surface, indicating a potential surface-association step.

Sources[2]pubmedHuman platelets and megakaryocytes express defensin alpha 1.Platelet's secreted DEFA1 can rebind to platelet's surface
Source records
1
Independent studies
1

Evidence boundary: Applies only to the source-defined population, formulation, dose, and assessment period.

Exact passages, locators, and provenance
  1. supports · Source-backed record
    “Platelet's secreted DEFA1 can rebind to platelet's surface”

    Human platelets and megakaryocytes express defensin alpha 1. · Abstract

    pubmed:31116063:f5370144b41f:f5370144b41f

What has been studied?

What the evidence says.

Study findings

Stimulation of MEG-01 cells with thrombopoietin induced secretion of DEFA1.

Sources[2]pubmedHuman platelets and megakaryocytes express defensin alpha 1.meanwhile, MEG-01 cells secreted DEFA1 when activated with thrombopoietin.
Source records
1
Independent studies
1

Evidence boundary: Applies only to the source-defined population, formulation, dose, and assessment period.

Exact passages, locators, and provenance
  1. supports · Source-backed record
    “meanwhile, MEG-01 cells secreted DEFA1 when activated with thrombopoietin.”

    Human platelets and megakaryocytes express defensin alpha 1. · Abstract

    pubmed:31116063:f5370144b41f:f5370144b41f

Study findings

The data support that both human platelets and megakaryocytes are capable of DEFA1 expression and secretion.

Sources[2]pubmedHuman platelets and megakaryocytes express defensin alpha 1.In summary, our data indicate that both, human platelets and megakaryocytes, can express and secrete DEFA1.
Source records
1
Independent studies
1

Evidence boundary: Applies only to the source-defined population, formulation, dose, and assessment period.

Exact passages, locators, and provenance
  1. supports · Source-backed record
    “In summary, our data indicate that both, human platelets and megakaryocytes, can express and secrete DEFA1.”

    Human platelets and megakaryocytes express defensin alpha 1. · Abstract

    pubmed:31116063:f5370144b41f:f5370144b41f

Study findings

The reported analytical performance includes accurate quantification of HNP 1-3 in synovial fluid with a turnaround time of 3 h and sample volume of approximately 50 μL.

Sources[1]doiAdvancing the Diagnosis of Periprosthetic Joint Infections: Integrated Microfluidic Platform for Alpha-Defensins-Specific Aptamer Selection and Its Analytical Applications.and it could accurately quantify HNP 1-3 in SF within 3 h with only ∼50 μL of SF.
Reported result
∼50 μL of SF; within 3 h
Source records
1
Independent studies
1

Evidence boundary: Applies only to the source-defined population, formulation, dose, and assessment period.

Exact passages, locators, and provenance
  1. supports · Source-backed record
    “and it could accurately quantify HNP 1-3 in SF within 3 h with only ∼50 μL of SF.”

    Advancing the Diagnosis of Periprosthetic Joint Infections: Integrated Microfluidic Platform for Alpha-Defensins-Specific Aptamer Selection and Its Analytical Applications. · Abstract

    doi:10.1021/acssensors.3c02034:7997f7b8a0e6:7997f7b8a0e6

Study findings

In a mouse NAFLD model induced by a high-fat diet, gavage with Lactobacillus gasseri SBT2055 was reported to upregulate intestinal mucosal expression of the antimicrobial peptide defensin alpha 1 (DEFA1).

Sources[3]pubmedThe Therapeutic Effect and Mechanism ofLactobacillus gardnerion Nonalcoholic Fatty Liver Disease.This study revealed that LG2055 gavage decreased serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), total cholesterol (TC), and triglyceride (TG), reduced lipid accumulation in liver tissue, promoted the expression of intestinal mucosal proteins mucin 2 (MUC2), defensin alpha 1 (DEFA1), and defensin alpha 4 (DEFA4), inhibited the levels of pro-inflammatory factors tumor necrosis factor-alpha (TNF-α) and interleukin (IL)-6, and increased the levels of anti-inflammatory factors IL-10 and immunoglobulin (Ig)A, IgG, and IgM.
Source records
1
Independent studies
1

Evidence boundary: Applies only to the source-defined population, formulation, dose, and assessment period.

Exact passages, locators, and provenance
  1. supports · Source-backed record
    “This study revealed that LG2055 gavage decreased serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), total cholesterol (TC), and triglyceride (TG), reduced lipid accumulation in liver tissue, promoted the expression of intestinal mucosal proteins mucin 2 (MUC2), defensin alpha 1 (DEFA1), and defensin alpha 4 (DEFA4), inhibited the levels of pro-inflammatory factors tumor necrosis factor-alpha (TNF-α) and interleukin (IL)-6, and increased the levels of anti-inflammatory factors IL-10 and immunoglobulin (Ig)A, IgG, and IgM.”

    The Therapeutic Effect and Mechanism ofLactobacillus gardnerion Nonalcoholic Fatty Liver Disease. · Abstract

    pubmed:41466504:6ccbaf190be7:6ccbaf190be7

Study findings

Both DEFA1 transcript (mRNA) and DEFA1 protein were detected in peripheral blood platelets and in the MEG-01 megakaryoblastic leukemia cell line.

Sources[2]pubmedHuman platelets and megakaryocytes express defensin alpha 1.Our data indicate that DEFA1 mRNA and protein are present in peripheral blood platelets and in the megakaryoblastic leukemia cell line (MEG-01).
Source records
1
Independent studies
1

Evidence boundary: Applies only to the source-defined population, formulation, dose, and assessment period.

Exact passages, locators, and provenance
  1. supports · Source-backed record
    “Our data indicate that DEFA1 mRNA and protein are present in peripheral blood platelets and in the megakaryoblastic leukemia cell line (MEG-01).”

    Human platelets and megakaryocytes express defensin alpha 1. · Abstract

    pubmed:31116063:f5370144b41f:f5370144b41f

Study findings

Upon activation with thrombin, adenosine diphosphate, and lipopolysaccharide, platelets released DEFA1 into the culture medium.

Sources[2]pubmedHuman platelets and megakaryocytes express defensin alpha 1.Furthermore, platelets secreted DEFA1 into the culture medium when activated with thrombin, adenosine diphosphate, and lipopolysaccharide;
Source records
1
Independent studies
1

Evidence boundary: Applies only to the source-defined population, formulation, dose, and assessment period.

Exact passages, locators, and provenance
  1. supports · Source-backed record
    “Furthermore, platelets secreted DEFA1 into the culture medium when activated with thrombin, adenosine diphosphate, and lipopolysaccharide;”

    Human platelets and megakaryocytes express defensin alpha 1. · Abstract

    pubmed:31116063:f5370144b41f:f5370144b41f

Risks and interactions

Risks, organized for scanning.

This profile does not yet contain a published summary for this topic. This is a coverage gap, not evidence that no research exists.

Products and regulatory status

Same ingredient. Different records.

This profile does not yet contain a published summary for this topic. This is a coverage gap, not evidence that no research exists.

Administration context

The practical clinical context.

This profile does not yet contain a published summary for this topic. This is a coverage gap, not evidence that no research exists.

Research status + gaps

What still needs better answers?

  • No publishable claim yet for: administration, contraindication, interaction, regulatory, safety
  • 46 compiled claim(s) withheld by automated assurance: assurance_score_below_0.58 (42), assurance_score_below_0.72 (3), current_regulatory_source_required (3), extraction_ambiguity (53), high_risk_requires_regulatory_or_two_independent_sources (3), no_direct_support (44), proposal_not_staged (1)
  • A source-backed introductory overview is not yet available.

These are the limits of this profile, not an exhaustive list of scientific uncertainties.

References + discovery

Open the records yourself.

  1. Advancing the Diagnosis of Periprosthetic Joint Infections: Integrated Microfluidic Platform for Alpha-Defensins-Specific Aptamer Selection and Its Analytical Applications. ↗

    doi · published 2024-04-09 · retrieved 2026-09-08T21:48:11Z

  2. Human platelets and megakaryocytes express defensin alpha 1. ↗

    pubmed · published 2020-01-01 · retrieved 2026-09-04T19:33:09Z

  3. The Therapeutic Effect and Mechanism ofLactobacillus gardnerion Nonalcoholic Fatty Liver Disease. ↗

    pubmed · published 2025-12-29 · retrieved 2026-08-26T08:42:26Z

Publication history and provenance

Version 1 · Automated assessment · 2026-09-08T21:48:11Z

659cc44a376ad1b1816612becb6381ff28b1ae1e1d494209deebd19dd3a03335